Conference warhed::astronomy

From:	VBORMC::"[email protected]" "MAIL-11 Daemon" 24-JAN-1997 00:34:02.29
To:	[email protected]
CC:	
Subj:	Earth & Sky: Week beginning 01/27/97

*  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

                             Earth & Sky
                Scripts for the week beginning 1/27/97

 *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

 Contents:
    Origin of Earth's Water
    World's Driest Places
    Soldag
    Protecting Sea Turtles
    Before the Bang
    Balloon Flights
    Groundhog Day
  Where to obtain additional information
  Unsubscription
  Copyright Notice

*********************************************************
Monday,  January 27, 1997
ORIGIN OF EARTH'S WATER
There are no natural processes on Earth that create water --
biologically or geologically.  But life as we know it would be
impossible without water.  Some theories on its origin -- after this on
Earth and Sky.
 _________________________________________________________

DB:  This is Earth and Sky, answering the question, "Where did Earth's
water come from?"

JB:  Scientists believe that the chemical constituents of water --
hydrogen and oxygen -- must have existed in the primordial cloud that
gave rise to our solar system four-and-a-half billion years ago.  The
early solar system was full of flying debris -- and as these chunks of
planetary material slammed into Earth, they could have initiated a
process whereby frozen hydrogen and oxygen were vaporized and released
into the atmosphere.  Two parts of hydrogen combined with one part of
oxygen to form H20 -- water vapor.

DB:  It's possible that comets also carried water to Earth.  Comets
would vaporize on impact -- and inject hydrogen and oxygen into Earth's
atmosphere.  And volcanoes may have contributed -- by bringing water
vapor from deep within Earth to the surface.

JB:  The early Earth was very hot -- its atmosphere could hold more
water vapor than today.  But Earth eventually cooled, and the vapor
began to condense out (SFX -- heavy rain), and Earth experienced the
biggest rainstorm in history.  Since then, the same water has cycled
from the land, to the air, and back again, for over three billion years.
 Our show is made possible by NOAA -- the National Oceanic and
Atmospheric Association -- and by the National Science Foundation.
We're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970127.html


*********************************************************
Tuesday,  January 28, 1997
WORLD'S DRIEST PLACES
When the water droplets that make up clouds get large enough, they fall
to the ground as rain.  But is there anyplace on Earth where this never
happens?  The world's driest places -- after this on Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky, with a good question from a five year old
about rainfall.

Tape:  "Hi, This is Taylor Rao in Austin, Texas.  I want to know if
there is any where in the world where it never rains?"

DB:  Taylor, it's not possible to record rainfall all over the globe.
But scientists are pretty sure that at least a little rain falls
everywhere on Earth.  There may be some places in Antarctica where it
never rains -- but, there, it snows.  Snow is just another way that
water falls from the sky.  Rain, snow, sleet, or hail are all
"precipitation" to scientists.

JB:  The driest place in the world is Arica, Chile in the Atacama
Desert.  The average rainfall there is about a centimeter a year, about
the depth of a bottle cap.  Sometimes the area can go for several years
without any rain at all.  Some other very dry places are the Sahara
Desert in Africa, large parts of Antarctica and the Gobi Desert in
China.

DB:  By contrast, the wettest place in the world is Mount Waialeale on
the Hawaiian island of Kauai.  Mount Waialeale gets about 1200
centimeters of rain each year -- that's about 500 inches.  It would take
fifteen hundred years for Arica to get that much rain.  Taylor, thank
you for your question.  Ask your Earth or sky question by calling
512-480-8773.  With thanks to the National Science Foundation, we're
Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970128.html


*********************************************************
Wednesday,  January 29, 1997
SOLDAG
Today people in Tromso, Norway, are celebrating the return of the sun.
We talk about a celebration of the sun -- Soldag or Sun Day -- after
this on Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky for Wednesday, January 29 -- joining the good
people of Tromso -- on the Arctic coast of Norway -- in greeting the sun
for the first time in many months.

DB:  The village of Tromso is located very far north on the globe.
Today is Soldag or Sun Day in Tromso.  The sun set there last November.
Today the sun reappears.

JB:  Statistics show more mental illness, physical sickness, domestic
strife, arrests for fighting, and suicides during the dark time.  Liquor
sales go up.  Children's grades go down.   One resident was quoted as
saying that the darkness brings out the worst in people:  ". . . envy,
jealousy, suspicion.  People. . . talk about the light constantly and
long for the sun to come back."

DB:  And today it does.  As in ancient times, it's a day of celebration
in Tromso.  Everyone hopes for a clear day so they can see the sun --
not just sense it behind clouds.

JB:  The sun comes up shortly after 11 a.m. in Tromso.  Just before that
time, people begin looking toward the south.   Many head for higher
ground to get a better view.  The sky brightens as it does before any
ordinary dawn.  And then the sun appears.  It pokes its head between the
same two hills every year.  For this Soldag or Sun Day, that's our show.
 With thanks to the National Science Foundation, we're Block and Byrd
for Earth and Sky.

http://www.earthsky.com/1997/es970129.html


*********************************************************
Thursday,  January 30, 1997
PROTECTING SEA TURTLES
Sea turtles, such as the loggerhead, Kemp's ridley, and leatherback, are
all either threatened or endangered.  Protecting sea turtles -- after
this on Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky for Thursday, January 30 -- on the plight of
sea turtles in the western hemisphere.

DB:  Sea turtles leave the safety of the oceans to lay their eggs on
beaches.  But, in recent years, they've had increasing competition from
humans for those beach-front properties.  Condominiums and hotels today
cover much of the shorelines that were once used by sea turtles.  To
make matters worse, sea turtles have a life cycle that makes them
vulnerable to rapid changes in their environment.  They live relatively
long lives and produce only a few offspring, somewhat late in life.

JB:  Also, these turtles can easily become caught in shrimping nets and
die if no precautions are taken by shrimpers.  The United States already
requires shrimpers to use devices that keep turtles from accidentally
ending up in their nets.

DB:  Now, a new international accord has been drafted that will go even
further to protect threatened sea turtles.  The accord should reduce
numbers of sea turtles caught and killed -- it'll do this by requiring
turtle exclusion devices to be used throughout the Americas.
Governments will also take measures to protect sea turtle nests, eggs,
and nesting beaches -- measures just as important as reducing accidental
turtle catches.

JB:  Our thanks to NOAA -- the National Oceanic and Atmospheric
Administration -- and to the National Science Foundation for making our
show possible.  We're Block and Byrd for Earth and Sky.


http://www.earthsky.com/1997/es970130.html


*********************************************************
Friday,  January 31, 1997
BEFORE THE BANG
After a recent show of ours on the Big Bang -- the event in which
scientists believe our universe was born -- several listeners wrote to
ask what existed before the Big Bang.  We talk about it -- after this on
Earth and Sky.
 _________________________________________________________

DB:  This is Earth and Sky.  Jim Cowart wants to know,  ". . . what
existed one second before (the Big Bang)?"

JB:  Jim, there are different models of how our universe came into
being.  None are proven -- and all have different ramifications for the
origin of our universe.  A popular model nowadays is called "inflation"
theory.  One of its associated ideas is that, at the time of the Big
Bang, the universe may have split into pieces.  If this did happen, then
what our telescopes see today is like a single patch on a vastly larger
quilt -- a piece in a larger, if not infinite, reality.

DB:  These other universes would have been spawned by  instabilities at
the subatomic, or quantum, level.  If you think of the imaginary quilt
of the "megauniverse" again you might imagine it having a fractal
structure -- that'd be like smaller patches inside larger patches.

JB:  In this view, universes come and go at a chaotic, eternally
self-reproducing pace.  Some of them may be so massive they quickly
collapse back onto themselves, while others expand so quickly that stars
never form.  It's almost like watching waves on some infinite ocean,
some rising, others falling.  Our whole universe may be just one thin
wave crest which turned out to be "just right" for stars, galaxies and
life to evolve.

DB:  We have more on this subject at our web site.  Learn how to reach
it with an email to [email protected].  With thanks to the National
Science Foundation, we're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970131.html


*********************************************************
Saturday,  February 1, 1997
BALLOON FLIGHTS
High altitude balloonists have to cope with extremely cold temperatures,
low air pressures and low levels of oxygen.  We talk about just how high
they fly  -- after this on Earth and Sky.
 _________________________________________________________

DB:  I'm Deborah Byrd.

JB:  And I'm Joel Block for Earth and Sky. Tim Airhart in Tulsa Oklahoma
writes:  "A co-worker was telling me about a TV show he had seen wherein
a man had flown a . . . balloon to an incredible height and parachuted
out of it wearing an oxygen mask and high altitude suit.  His camera
lens immediately frosted over from the low temperature.  What is the
record height for  hot air balloons?   . . . We look forward to an
uplifting answer."

DB:  Tim, first, it wasn't a hot air balloon that your friend saw on TV.
 Hot air balloons don't fly as high as helium balloons because they need
oxygen for their burners to work.  And the higher they rise, the thinner
the air -- so less oxygen is available.  The all-time record for hot air
balloons is over 20,000 meters -- over 65,000 feet -- set in 1988 by Per
Lindstrand of the United Kingdom.

JB:  The man your friend saw on TV was Joe Kittinger, who now lives in
Florida.   Mr. Kittinger told us he was flying a helium balloon at an
altitude of more than 31,600 meters -- more than 100,000 feet -- when he
parachuted out.  The year was 1960.  His flight set a new altitude
record, which was broken a year later by the current record holder,
Malcom Ross.  Ross flew to over 35,000 meters -- or over 113,000 feet --
on a balloon launched from an aircraft carrier.  That's our show for
today.  With thanks to the National Science Foundation, we're Block and
Byrd for Earth and Sky.


http://www.earthsky.com/1997/es970201.html


*********************************************************
Sunday,  February 2, 1997
GROUNDHOG DAY
Nowadays the seasons are said to begin at the equinoxes and solstices.
But some have argued they could just as well begin on the cross-quarter
days.   More on today's cross-quarter day -- after this on Earth and
Sky.
 _________________________________________________________

JB:  This is Earth and Sky for Sunday, February 2 -- what we celebrate
as Groundhog Day.

DB:  This is really an astronomical holiday -- one of the year's four
cross-quarter days.  Each cross-quarter "day" actually represents a
collection of dates more or less midway between a solstice and an
equinox.  February 2 is the year's first cross-quarter day -- and it's
also marked by the celebration of Candlemas in the Roman Catholic and
other religions.

JB:  Here in North America, we celebrate today's cross quarter day as
Groundhog Day.   In our culture and many others, today is a time for
forecasting the weather -- when the legendary groundhog looks for his
shadow.   If he sees it, he's said to jump back down underground --
dooming us all to six more weeks of winter.  On the other hand, a cloudy
Groundhog Day forecasts an early spring.

DB:  The second cross-quarter day comes on April 30 -- May Eve -- or on
May Day, May 1.   The third one comes on August 1 -- it's Lammas, an old
harvest festival.  Then there's the fourth and final cross-quarter day
for the year -- the most sinister since it comes at a time when there's
not much daylight in the northern hemisphere.  We in America celebrate
it by dressing as witches and ghosts at Halloween.

JB:  We have more on Groundhog Day at our web site.  Learn how to reach
it with an email to [email protected].   We produce our show thanks to
the National Science Foundation.  I'm  Joel Block with Deborah Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970202.html

--------------------------------------------------------------------
You can obtain the text of these mailings, along with educational
materials and Real Audio recordings of our shows via anonymous FTP at:
          ftp://earthsky.com

For more information about Earth & Sky please visit our web site at:
          http://www.earthsky.com

Or email us at:
         [email protected]
--------------------------------------------------------------------

To unsubscribe from this list e-mail to:
          [email protected]

The subject line will be ignored.  In the BODY of the message write:
          UNSUBSCRIBE

Please use this address only for subscribing or unsubscribing.
--------------------------------------------------------------------

All Earth & Sky materials are copyrighted by Byrd & Block Communications
Inc. Permission to use, copy and distribute these materials without fee
is hereby granted, provided that:
    the above copyright notice appear in all copies and
    the materials are not redistributed for profit.

The Earth & Sky logo and "Earth & Sky" are registered trademarks of Byrd
& Block Communications Inc.
###



% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Received: from mail.vbo.dec.com (mail.vbo.dec.com [16.36.208.34]) by vbormc.vbo.dec.com (8.7.3/8.7) with ESMTP id BAA26926 for <[email protected]>; Fri, 24 Jan 1997 01:31:05 +0100
% Received: from server21.digital.fr (server21.digital.fr [193.56.15.21]) by mail.vbo.dec.com (8.7.3/8.7) with ESMTP id BAA04838 for <[email protected]>; Fri, 24 Jan 1997 01:35:43 +0100 (MET)
% Received: from tpoint.net (challenger.tpoint.net [204.29.207.17]) by server21.digital.fr (8.7.5/8.7) with ESMTP id BAA26092 for <[email protected]>; Fri, 24 Jan 1997 01:37:26 +0100 (MET)
% Received:  by tpoint.net (8.8.2/25-eef) id WAA26495; Thu, 23 Jan 1997 22:47:50 GM
% Resent-Date: Thu, 23 Jan 1997 22:47:50 GMT
% X-Sender: [email protected]
% Message-Id: <v03007802af0d957f43da@[206.160.162.36]>
% Mime-Version: 1.0
% Content-Type: text/plain; charset="us-ascii"
% Date: Thu, 23 Jan 1997 16:25:38 -0600
% To: [email protected]
% From: Chris Luther <[email protected]>
% Subject: Earth & Sky: Week beginning 01/27/97
% Resent-Message-ID: <"2fBlL1.0.bT6.3g-vo"@challenger>
% Resent-From: [email protected]
% Reply-To: [email protected]
% X-Mailing-List: <[email protected]> archive/latest/66
% X-Loop: [email protected]
% Precedence: list
% Resent-Sender: [email protected]

From:	VBORMC::"[email protected]" "MAIL-11 Daemon" 31-JAN-1997 22:59:43.96
To:	[email protected]
CC:	
Subj:	Earth & Sky : Week beginning 2/3/97

*  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

                                  Earth & Sky
             Scripts for the week beginning 2/3/97

 *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

 Contents:
       Old Moon, New Comet
       Mauna Loa
       Growing Season Longer?
       Amethyst
       High Tides
       Earthshine
       Cape Hatteras Lighthouse
  Where to obtain additional information
  Unsubscription
  Copyright Notice

*********************************************************
Monday,  February 3, 1997
OLD MOON, NEW COMET
How to use an "old" moon to locate a "new" comet.  We'll talk more about
how you can find what may become this decade's brightest comet -- Comet
Hale-Bopp -- after this on Earth and Sky.
 _________________________________________________________

JB: This is Earth and Sky for Monday, February 3.  In the next two
mornings, the waning moon makes a pretty sight in the predawn sky --
and, if you're hearing us from the northern hemisphere, you can use the
moon to locate Comet Hale-Bopp.

DB:  This comet is predicted to become the brightest one of this decade
-- brighter than Comet Hyakutake, which many people saw last year.
Hale-Bopp won't be at its brightest for another couple of months -- but
you might be able to catch a glimpse of it now.

JB:  Go outside around 5:30 a.m. -- when the sky is still dark, but
there's a hint of dawn.  Look low in the southeastern sky. You'll see a
slender crescent moon -- what many people call an "old" moon.

DB:  Now to see the comet.  Look to the moon's left, or due east along
that predawn horizon.  The bright star you'll see there is Altair in the
constellation Aquila the Eagle.  The comet lies to the upper left of
Altair.  It should be visible as a small hazy patch of light.
Binoculars will show it better and may reveal the comet's tail.

JB: Comet Hale-Bopp is fast approaching the Earth and sun.  As it does
so, it's growing brighter on our sky's dome.  As seen from this
hemisphere, it'll be a wonderful sight in the evening sky in late March
and early April.  That's our show for today -- you can reach us by
calling 512-480-8773.  Our show is made possible by the National Science
Foundation.  I'm Joel Block with Deborah Byrd for Earth and Sky.


http://www.earthsky.com/1997/es970203.html


*********************************************************
Tuesday,  February 4, 1997
MAUNA LOA
High on the slopes of a Hawaiian volcano, scientists are keeping an eye
on the health of our planet's atmosphere.  More on measuring carbon
dioxide at the Mauna Loa Observatory in Hawaii -- after this on Earth
and Sky.
 _________________________________________________________

JB:  This is Earth and Sky for Tuesday, February 4 -- on carbon dioxide
gas in Earth's atmosphere.

DB:  Carbon dioxide, also known as CO2, makes up a tiny --but very
important -- part of the atmosphere.  Plants essentially breathe in the
gas as they grow.  It's thought that, since the start of the Industrial
Revolution, the delicate balance of CO2 in the air has begun to change.
Humans add CO2 to the air when they burn coal in power plants -- and cut
down and burn forests.  Because this gas can trap heat in the
atmosphere, many scientists  believe the excess will contribute to a
global warming in the coming century.

JB:  Carbon dioxide in the atmosphere is increasing.   In the late
1950s, the U.S. Weather Bureau set up instruments on the barren slopes
of the Mauna Loa volcano in Hawaii.  Every four hours, these sensitive
instruments measure the amount of carbon dioxide in the air over Mauna
Loa.  The result is the world's longest uninterrupted record of carbon
dioxide in the atmosphere.  This record stretches from 1958 to the
present.

DB:  And the record shows that carbon dioxide concentrations have risen
since 1958.  Tomorrow -- how scientists are finding evidence that the
world may get warmer, in an observed change in the timing of the growing
season.  Today's show was made possible by NOAA - -the National Oceanic
and Atmospheric Administration -- and by the National Science
Foundation.  We're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970204.html


*********************************************************
Wednesday,  February 5, 1997
GROWING SEASON LONGER?
Too much carbon dioxide in Earth's atmosphere may be making our world
warmer.  How there's evidence of climate change being seen in the way
plants grow  -- after this on Earth and Sky.
 _________________________________________________________

DB:  This is Earth and Sky for Wednesday, February 5.  Yesterday we
talked about how scientists have measured an increase in carbon dioxide,
or CO2, in Earth's atmosphere.

JB:  The excess CO2 may be responsible for rising temperatures on Earth
-- and it may also affect how plants grow, according to Charles Keeling
of the Scripps Institution of Oceanography.  He and others believe they
see an increase in the length of the growing season over the past 20
years.

DB:  Plants take in a deep "breath" of carbon dioxide every spring, just
as they begin to grow again after the dormancy of winter.  Then in the
fall, as plant growth slows down, the amount of carbon dioxide in the
air increases.  Scientists have been charting this pulse of carbon
dioxide since the early 1958.

JB:  And, in that time , the peak of the growing season -- when plants
are breathing in the most CO2 -- has moved up by about a week, according
to these scientists. They think the growing season is becoming longer --
as plants take in longer and deeper breaths of carbon dioxide, in
response to rising temperatures.  It also looks as though, the farther
north you go and still and find forests, the more obvious these changes
become.  So scientists may be looking to areas like central Canada and
southern Siberia to see some clear physical effects of climate change.
With thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970205.html


*********************************************************
Thursday,  February 6, 1997
AMETHYST
Saint Valentine was said to have worn an amethyst ring, engraved with
the figure of Cupid. We talk more about February's birthstone -- a stone
once associated with sobriety  -- the amethyst -- after this on Earth
and Sky.
 _________________________________________________________

JB:  This is Earth and Sky for Thursday, February 6 -- on the subject of
birthstones.

DB:  It's said that twelve gems appeared on the breastplate of the High
Priest of the Hebrews -- as dictated by Moses after 40 days in the
mountains -- in the year 1250 BC. These gems were later linked with
signs of the Zodiac -- and later with months of the year.

JB:  February's birthstone is the amethyst.  It's a transparent form of
quartz, whose crystals grow underground under ideal conditions of heat
and pressure.  The amethyst contains more iron oxide than any other
variety of quartz.  Its color, which can range from a faint to rich
purple, is thought by some to result from the iron oxide.  If you own an
amethyst, be forewarned that heat can cause it to change color.

DB:  The word amethyst comes from a Greek word meaning "not drunk."
According to an ancient myth, Bacchus, god of wine, was said to be
offended by Diana, goddess of the hunt.  He was so angry that he swore
to set wild tigers on the first person he met.  That person was Amethyst
-- a beautiful maiden -- who called on the goddess to save her.  Diana
changed the maiden to a pure, white, sparkling image of stone.  Bacchus
poured grape wine over the statue -- and transformed it to a violet
color.  After that, an amethyst was said to keep people from becoming
intoxicated.   With thanks to the National Science Foundation, we're
Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970206.html


*********************************************************
Friday,  February 7, 1997
HIGH TIDES
It's possible to predict some especially high tides today.  We talk
about the relative positions of the moon and sun -- and about the moon's
exceptional nearness to Earth today -- after this on Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky for Friday, February 7.  Today, people living
near a coast can expect higher-than-usual tides.

DB:  The moon's gravity creates the tides -- two high tides and two low
tides each day.  But the sun's gravity affects the tides, too -- its
effect is a little less than half that of the moon.  So twice each month
-- when the sun, moon and Earth lie more or less in a straight line in
space -- the tide is amplified by the combined gravity of the sun and
moon.  Then we have higher-than-usual "spring" tides.

JB:  The word "spring" in this case has nothing to do with the season.
And again spring tides come twice a month, as the Earth, sun  and moon
pursue their orderly motions through space.  But sometimes another
astronomical event coincides with a spring tide to amplify the effect
even more -- and that's when the moon is at perigee, or closest to Earth
-- so that it's pull on Earth is strongest.  That's what's happening
today.  The moon is new today -- the Earth, sun and moon are lined up.
Also, the moon comes closest to Earth today for this monthly orbit -- in
fact, it's closest today for this year -- about 356,847 kilometers from
Earth.

DB:  And that makes very high tides and very low tides very likely.
What's not predictable is the effect of the weather.  The potential for
severe coastal flooding exists if a strong weather front occurs at the
same time as high tide.  With thanks to the National Science Foundation,
we're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970207.html


*********************************************************
Saturday,  February 8, 1997
EARTHSHINE
In the next few evenings, you might notice a pale glow on the darkened
portion of the crescent moon.  We answer a listener's question on
whether this "earthshine" is getting brighter -- after this on Earth and
Sky.
 _________________________________________________________

DB:  This is Earth and Sky for Saturday, February 8, with a question
from Jeff Truelsen of Ithaca, New York.

JB:  He writes:  "It seems to me that when I look at the moon on nights
when it's not full, it is easier to see the "dark" part than it was 20
or 30 years ago. . .  Is it possible that the amount of manmade light
coming from the Earth is being reflected . . . more than it used to, or
is there another explanation?"

DB:  Jeff, that pale glow on the dark part of the moon is called
"earthshine."  It's most noticeable when the moon appears as a crescent
-- as it does in the next few evenings.  City lights have no effect on
earthshine for several reasons.  Most importantly -- earthshine comes
from sunlight reflected off Earth's day side, where most city lights are
turned off.

JB:  A few years ago scientists began precisely measuring the brightness
of earthshine.  If they detect a change in its brightness over the
coming decades, they'll probably attribute that change not to city
lights -- but instead to Earth's overall cloud cover.  Some
climatologists are suggesting that Earth's cloud cover may have
increased since the 1950s.  The increase may have been caused by
pollution -- or even global warming.  If there are truly more clouds
covering Earth today, our planet would reflect more light -- and
earthshine on the moon might look a little brighter.  Jeff, thanks for
your question -- and thanks to the National Science Foundation for
making our show possible.  We're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970208.html


*********************************************************
Sunday,  February 9, 1997
CAPE HATTERAS LIGHTHOUSE
The Cape Hatteras Lighthouse was built during the golden age of
engineering -- about the same time as the Brooklyn Bridge and the Statue
of Liberty.  The future of this grand lighthouse -- today on Earth and
Sky.
 _________________________________________________________

JB:  This is Earth and Sky -- with a note from Mark Belles.

DB:  He writes, "There are discussions of how beach erosion is
threatening the Cape Hatteras Lighthouse.  Apparently there have been
several attempts to stabilize the beach that've failed."

JB:  The Cape Hatteras Lighthouse is the tallest brick lighthouse in the
United States.  Its light still provides a beacon for fishermen and
recreational boaters.  When it was built in 1870, the lighthouse stood
1500 feet -- or about 450 meters -- from the North Carolina shoreline.
But global sea levels have been rising for many years -- and the shore
around the lighthouse is unstable.  Several attempts at stabilizing the
shore have failed to hold back the rising sea.  Today, the shore is only
a few meters from the lighthouse.

DB:  Scientists predict that if nothing is done to preserve the
lighthouse it'll eventually fall into the sea.  And some have suggested
that it would be best to let it do just that.  It's a good example, they
say, of why building permanent structures on our ever-shifting coasts is
not a sound practice.  Others would rather preserve this landmark.  One
proposal is to build a sea wall around the lighthouse.  As sea level
rises, the lighthouse would eventually be surrounded by water.  Another
suggestion is to move the entire lighthouse back from the shore another
450 meters -- as far as it was from the water when it was built in 1870.
 That's our show for today -- made possible by the National Science
Foundation.  We're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970209.html

--------------------------------------------------------------------
You can obtain the text of these mailings, along with educational
materials and Real Audio recordings of our shows via anonymous FTP at:
          ftp://earthsky.com

For more information about Earth & Sky please visit our web site at:
          http://www.earthsky.com

Or email us at:
         [email protected]
--------------------------------------------------------------------

To unsubscribe from this list e-mail to:
          [email protected]

The subject line will be ignored.  In the BODY of the message write:
          UNSUBSCRIBE

Please use this address only for subscribing or unsubscribing.
--------------------------------------------------------------------

All Earth & Sky materials are copyrighted by Byrd & Block Communications
Inc. Permission to use, copy and distribute these materials without fee
is hereby granted, provided that:
    the above copyright notice appear in all copies and
    the materials are not redistributed for profit.

The Earth & Sky logo and "Earth & Sky" are registered trademarks of Byrd
& Block Communications Inc.
###



% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Received: from mail.vbo.dec.com (mail.vbo.dec.com [16.36.208.34]) by vbormc.vbo.dec.com (8.7.3/8.7) with ESMTP id XAA04014 for <[email protected]>; Fri, 31 Jan 1997 23:56:20 +0100
% Received: from server21.digital.fr (server21.digital.fr [193.56.15.21]) by mail.vbo.dec.com (8.7.3/8.7) with ESMTP id AAA07598 for <[email protected]>; Sat, 1 Feb 1997 00:01:07 +0100 (MET)
% Received: from tpoint.net (challenger.tpoint.net [204.29.207.17]) by server21.digital.fr (8.7.5/8.7) with ESMTP id AAA11778 for <[email protected]>; Sat, 1 Feb 1997 00:02:59 +0100 (MET)
% Received:  by tpoint.net (8.8.2/25-eef) id UAA01877; Fri, 31 Jan 1997 20:41:38 GM
% Resent-Date: Fri, 31 Jan 1997 20:41:38 GMT
% X-Sender: [email protected]
% Message-Id: <v03007800af16c6cb6d6e@[206.160.162.41]>
% Mime-Version: 1.0
% Content-Type: text/plain; charset="us-ascii"
% Date: Fri, 31 Jan 1997 14:43:59 -0600
% To: [email protected]
% From: Angela Lucignani <[email protected]>
% Subject: Earth & Sky : Week beginning 2/3/97
% Resent-Message-ID: <"XdlLN3.0.xS.iZbyo"@challenger>
% Resent-From: [email protected]
% Reply-To: [email protected]
% X-Mailing-List: <[email protected]> archive/latest/67
% X-Loop: [email protected]
% Precedence: list
% Resent-Sender: [email protected]

From:	VBORMC::"[email protected]" "MAIL-11 Daemon" 15-FEB-1997 00:49:19.87
To:	[email protected]
CC:	
Subj:	Earth & Sky: Week beginning 2/17/97 

*  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

                                     Earth & Sky
                 Scripts for the week beginning 2/17/97

 *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

 Contents:
        Moon's Day and Night
        Journey Into A Black Hole
        Black Hole Sun
        Black Hole in Milky Way
        Regulus and Moon
        Transuranium Elements
        Precession
  Where to obtain additional information
  Unsubscription
  Copyright Notice

*********************************************************
Monday,  February 17, 1997
MOON'S DAY AND NIGHT
A lot of people think that one side of the moon is in permanent
darkness.  You sometimes hear the phrase "dark side of the moon."  Why
that's not so -- and about  temperatures on the moon -- after this on
Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky, with a question from Alex Bernstein.

Tape:  "Hi, I saw you on the Internet and have a question.  Interested
in knowing what the temperature on the lunar surface is, both on the
dark side and the light side of the moon."

DB:  Alex, I guess you know there are no permanent dark and light sides
of the moon.  The whole surface of the moon goes in and out of daylight
and darkness, just as Earth does.  There is a far side of the moon that
we never see from Earth.  And there's the near side of the moon that we
do see.  But -- since the moon rotates about once a month -- the whole
lunar surface, except the poles, is in daylight for about two weeks, and
darkness for about two weeks.

JB:  Partly because day and night last so long on the moon -- but mostly
because the moon doesn't have an atmosphere -- the range in lunar
temperatures is extreme.  At high noon on the moon -- in other words, at
a place where the sun is directly overhead -- the temperature has been
measured as high as 115 degrees Celsius, or about 240 degrees
Fahrenheit.  That's hotter than the boiling point of water.  Meanwhile,
in the dead of the lunar night, temperatures have been measured as low
as -180 degrees Celsius -- that's about 290 degrees below zero
Farenheit.

DB:  Alex, thanks for your question.  If you have an Earth or sky
question, you can send it to us by email -- write to [email protected].
With thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970217.html


*********************************************************
Tuesday,  February 18, 1997
JOURNEY INTO A BLACK HOLE
If you were bold enough to plunge into a black hole, you'd be
simultaneously stretched to an indefinite length and compressed into
bits.  More on a journey into a black hole -- after this on Earth and
Sky.
 _________________________________________________________

DB:  This is Earth and Sky, with a question from Jen from Randolph High
School in New Jersey.

JB:  She writes, "What would happen if I entered a black hole?"

DB:  Jen, black holes are regions of powerful gravity, and they come in
very different sizes -- from not much more massive than our sun -- to
billions of solar masses.  Let's say you pass over the "event horizon"
-- that's sort of a boundary -- of a black hole that's a billion times
the sun's mass.  Such massive black holes may be at the centers of
galaxies.  At first, you wouldn't feel anything strange.  You wouldn't
notice a physical change in your surroundings -- unless you tried to go
back the way you came.  Then no amount of energy would be able to push
you back out of the black hole.

JB:  An object's gravity gets stronger as you get closer to it.   If you
were falling into a black hole, the gravitational pull on your feet
would be much greater than that on your head -- assuming you were
falling feet first!  You'd be stretched into an indefinite length as you
got closer to the hole.  The hole's gravity would also compress your
body -- it'd squeeze your two shoulders together, for example -- and
ultimately stretch and squeeze the very atoms that make up your body!
The result -- the total destruction of your body on its journey into a
black hole.

DB:  We have more on this subject at our web site.  Learn how to reach
it with an email to [email protected]  With thanks to the National
Science Foundation, we're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970218.html


*********************************************************
Wednesday,  February 19, 1997
BLACK HOLE SUN
Near a black hole, the force of gravity is so strong that even light
can't escape.  But, from a distance, a black hole's gravity would be . .
. unremarkable.   If our sun became a black hole -- after this on Earth
and Sky.
 _________________________________________________________

DB: This is Earth and Sky with a question from Geneva, New York.

JB: The Burdick family wrote to suggest this scenario:  "Suppose the sun
were suddenly converted into a black hole.  Would the Earth remain in
its orbit, or would it be sucked into the black hole?"

DB:  Well, first, it's tough to think of how the sun could become a
black hole -- because whether a star will or won't evolve in this way
depends on how massive it is -- and the sun isn't massive enough.

JB:  But suppose the sun's existing mass got squeezed down into an
extremely small volume.  If the volume were small enough -- six
kilometers across or less -- the sun would become a black hole.

DB:  Now consider the force of gravity.  It depends on two things -- the
masses of the objects involved -- and the distance between them.  The
closer together two objects are, the stronger the pull.  If the sun were
squeezed into a black hole, an object near it would feel a gravitational
pull more than 50 billion times stronger than that at the sun's surface
now. That's because the sun would occupy a much smaller space -- and the
object could get much closer to its center.

JB:  Meanwhile,  the distance of Earth from the black hole's center
wouldn't have changed.  And the sun's mass wouldn't  have changed.  So
Earth's orbit wouldn't change.  We thank the Burdick family for their
question.  Ask your question with an email to [email protected].  With
thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970219.html


*********************************************************
Thursday,  February 20, 1997
BLACK HOLE IN MILKY WAY
For decades, astronomers have intensely studied the center of our Milky
Way galaxy -- but its contents are still hotly debated.  More on a
possible black hole at the center of the Milky Way -- after this on
Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky, on a possible black hole at the center of
our Milky Way galaxy.

DB:  There are thought to be supermassive black holes in the cores of
many other galaxies external to our Milky Way.  Some may have a billion
times the sun's mass -- the black hole in our galaxy may be a million
times more massive than our sun.   Astronomers believe that -- if it
exists -- the Milky Way's black hole should be swallowing up stars and
gas.  In that case, they might see evidence of the hole in the light
emitted by these objects as fall toward the black hole.  Further
evidence would come from the motions of stars near the center of our
galaxy.  A supermassive black hole would control traffic patterns in the
galaxy's core -- it would dictate the velocities of the surrounding
stars.

JB:  So astronomers know what to look for -- but it's not easy for them
to interpret what they see.  The motions of stars around the galaxy's
core do support the existence of a giant black hole in the core of our
galaxy -- but the light observed in the region doesn't.  It's possible
that the light in this region isn't as expected -- because there's very
little gas left near the black hole to emit light while falling in.  Or
maybe the black hole traps most of the light before astronomers can
detect it.   At this time, the question of whether our galaxy has a
central, supermassive black hole is still open -- and astronomers are
still looking.

DB:  Thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970220.html


*********************************************************
Friday,  February 21, 1997
REGULUS AND MOON
There were four Royal Stars known to the early stargazers -- and one of
them is near the moon tonight.  We talk about a modern perception of the
star Regulus -- after this on Earth and Sky.
 _________________________________________________________

DB:  This is Earth and Sky for Friday, February 21.  If you look outside
this evening, you'll see a bright star near the moon.

JB:  You'll find the moon low in the eastern sky when the sun goes down
tonight.  By mid-evening, the moon will be well up in the east.  The
moon will be full tomorrow, and it's beginning to loom very large and
full-looking in our night sky.  The bright star near tonight's moon is
Regulus -- the heart of the Lion in the constellation Leo.

DB:  Regulus is in the head and shoulders of Leo.   This part of the
Lion makes what's called an asterism -- that's a noticeable pattern of
stars.  In this case, the pattern is that of a backwards question mark
-- the question mark is upside down as seen from the southern
hemisphere.  This pattern, or asterism, in the constellation Leo is
called the Sickle.  Regulus is the brightest star in the pattern --
located at the bottom of the question mark.

JB:  Regulus is drowned in the moon's glare tonight, tomorrow night the
moon has moved eastward on the sky's dome.  Then you'll see that Regulus
is a blue-white star.  This star is located about 85 light-years away.
It's thought to be about three times as massive as our sun, and it burns
brighter than our sun.  Regulus will use its primary nuclear fuel --
hydrogen -- in only about 200 million years.  Meanwhile, the lifetime of
our sun is thought to be more like nine billion years.  With thanks to
the National Science Foundation, we're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970221.html


*********************************************************
Saturday,  February 22, 1997
TRANSURANIUM ELEMENTS
Scientists in laboratories have been creating new elements heavier than
uranium.  We answer a listener's question about the usefulness of these
"transuranium elements" -- after this on Earth and Sky.

 _________________________________________________________

JB:  This is Earth and Sky.  Today -- a question from Andy Landen, who
heard our show on transuranium elements.

DB:  Uranium has 92 protons in its nucleus.  Transuranium elements have
93 and up.  These elements can be created under special laboratory
conditions, by driving together the nuclei of various atoms.

JB:  And Andy wants to know, "Do such...elements occur naturally
elsewhere in the universe?  And do we have a potential future use for
such heavy elements?"

DB:  Andy, up to now the only transuranium element found in nature has
been plutonium -- found in very rich uranium ore and in a rare Earth
mineral called bastnasite.  Other transuranium elements may be created
inside supernovae -- stars that explode -- but so far we haven't
detected these elements on Earth.

JB:  Plutonium is the best known transuranium element for its use in
nuclear power plants and weapons.  It was also used to power remote
sensing instrument packages on five unmanned Apollo moon flights and on
fly-by missions to the planets.  Other transuranium elements have been
used for analyzing metal ores, in radiation therapy for cancer, in
cardiac pacemakers, and in gauges and smoke alarms.  All the
transuranium elements are radioactive -- and have to be handled with
special equipment and precautions.

DB:  The National Science Foundation makes our show possible.  We're
Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970222.html


*********************************************************
Sunday,  February 23, 1997
PRECESSION
Earth makes one complete spin on its axis every day.  Earth also wobbles
like a top spinning on a table -- but one wobble of the Earth takes
nearly 26 thousand years.  We talk about the precession of the Earth --
after this on Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky, with a question from Dale Croswell about
precession.

DB:  Dale writes, "The Earth's axis is now tilted at about twenty-three
and one-half degrees.  Over a long time, will this tilt angle increase
so that the Earth's wobble will become ever  'flatter' like that of a
spinning top?"

JB: Maybe you've noticed a spinning top start to wobble.  This wobbly
motion is called "precession."  As the top loses energy through
friction, it tilts more and more -- until it falls over.

DB: The spinning Earth also undergoes this motion of precession.  One
complete wobble of the Earth takes 26 thousand years.  But will Earth's
axis begin to tilt more and more?  The answer is that no one knows for
sure.  Precession is caused by the moon and the sun tugging on Earth's
equatorial bulge.  The moon and sun also cause the rise and fall of
ocean tides -- and the movement of the tides are causing the spin of the
Earth to slow down.

JB:  If the moon's gravity had its way, it'd force Earth's axis to be at
right angles to the moon's orbit.  Earth would be completely upright.
As Earth spins more slowly, this would someday be the natural
orientation of the Earth.   But the sun, meanwhile, exerts its pull on
Earth, too -- so we really have a three-way tug-of-war going on.  Even
the experts can't predict what will happen to this chaotic system.  You
can reach us with an email to [email protected].  The National Science
Foundation makes our show possible.  We're  Block and Byrd for Earth and
Sky.

http://www.earthsky.com/1997/es970223.html

--------------------------------------------------------------------
You can obtain the text of these mailings, along with educational
materials and Real Audio recordings of our shows via anonymous FTP at:
          ftp://earthsky.com

For more information about Earth & Sky please visit our web site at:
          http://www.earthsky.com

Or email us at:
         [email protected]
--------------------------------------------------------------------

To unsubscribe from this list e-mail to:
          [email protected]

The subject line will be ignored.  In the BODY of the message write:
          UNSUBSCRIBE

Please use this address only for subscribing or unsubscribing.
--------------------------------------------------------------------

All Earth & Sky materials are copyrighted by Byrd & Block Communications
Inc. Permission to use, copy and distribute these materials without fee
is hereby granted, provided that:
    the above copyright notice appear in all copies and
    the materials are not redistributed for profit.

The Earth & Sky logo and "Earth & Sky" are registered trademarks of Byrd
& Block Communications Inc.
###



% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Received: from mail.vbo.dec.com (mail.vbo.dec.com [16.36.208.34]) by vbormc.vbo.dec.com (8.7.3/8.7) with ESMTP id BAA19988 for <[email protected]>; Sat, 15 Feb 1997 01:46:09 +0100
% Received: from server21.digital.fr (server21.digital.fr [193.56.15.21]) by mail.vbo.dec.com (8.7.3/8.7) with ESMTP id BAA07174 for <[email protected]>; Sat, 15 Feb 1997 01:50:54 +0100 (MET)
% Received: from tpoint.net (challenger.tpoint.net [204.29.207.17]) by server21.digital.fr (8.7.5/8.7) with ESMTP id BAA23638 for <[email protected]>; Sat, 15 Feb 1997 01:53:07 +0100 (MET)
% Received:  by tpoint.net (8.8.2/25-eef) id WAA16844; Fri, 14 Feb 1997 22:30:08 GM
% Resent-Date: Fri, 14 Feb 1997 22:30:08 GMT
% X-Sender: [email protected]
% Message-Id: <v0300780aaf293e64b9df@[206.160.162.41]>
% Mime-Version: 1.0
% Content-Type: text/plain; charset="us-ascii"
% Date: Fri, 14 Feb 1997 16:33:04 -0600
% To: [email protected]
% From: Angela Lucignani <[email protected]>
% Subject:  Earth & Sky: Week beginning 2/17/97 
% Resent-Message-ID: <"jfksz.0.j64.ITE1p"@challenger>
% Resent-From: [email protected]
% Reply-To: [email protected]
% X-Mailing-List: <[email protected]> archive/latest/69
% X-Loop: [email protected]
% Precedence: list
% Resent-Sender: [email protected]

From:	VBORMC::"[email protected]" "MAIL-11 Daemon" 22-FEB-1997 00:35:35.14
To:	[email protected]
CC:	
Subj:	Earth & Sky : Week beginning 2/24/97

*  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

                                     Earth & Sky
                 Scripts for the week beginning 2/24/97

 *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

 Contents:
        Mars, Moon, and Comet
        Tiny Bubbles
        The End of Earth
        Speed of Gravity
        Dinosaur Feathers
        Month of March
        How to See Mars
  Where to obtain additional information
  Unsubscription
  Copyright Notice

*********************************************************
Monday,  February 24, 1997
MARS, MOON, AND COMET
We tell you how to see the moon passing near the red planet Mars -- and
also how to see the new comet that's becoming more and more visible --
after this on Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky for Monday, February 24.  I'm Joel Block.

DB:  And I'm Deborah Byrd.  All night tonight, you can see the moon near
the red planet Mars.  And if you're up before dawn this week, you can
also spot a comet.

JB: The moon and Mars come up in mid-evening tonight.  For the rest of
the night, Mars is the brightest object near the moon on the sky's dome.
 By tomorrow night, the moon will have moved on, as it pursues its
endless eastward orbit around Earth.  On Tuesday evening, the moon will
appear east of Mars on our sky's dome.  Then it'll be easy to see why
Mars is called the red planet -- once it's out of the moon's glare, its
reddish color will stand out clearly.  On Tuesday night, you'll see
another bright object near the moon.  This will be the star Spica in the
constellation Virgo.

DB:  Now -- Comet Hale-Bopp -- which may become this decade's brightest
comet -- and which you can see right now only if you're up before dawn.
To find the comet in the predawn hours, face the eastern sky -- the part
of the sky where the sun will rise.  About one quarter of the way up the
sky, look for a fuzzy patch.  This is Comet Hale-Bopp.  It'll look like
a star with haze around it.  You may see a faint tail extending upward.
Binoculars will help you see it better.  Comet Hale-Bopp is approaching
the Earth and sun and becoming brighter each week.  In just about a
month, it'll be at its brightest.

JB:  With thanks to the National Science Foundation, we're Block and
Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970224.html


*********************************************************
Tuesday,  February 25, 1997
TINY BUBBLES
Without soap, it'd be a lot harder to get the dinner dishes clean.  But
what is it that soap has that water alone doesn't have?  We answer a
listener's question on how soaps and detergents get things clean --
after this on Earth & Sky.
 _________________________________________________________

JB: This is Earth and Sky with a question from a listener.

DB:  Ray Sarmiento writes from California: "Why do we use soap or
detergents in washing clothes or washing dishes?  How come water being a
universal solvent is not enough?"

JB:  Ray, water isn't a universal solvent.  Some things dissolve in
water, and others -- such as grease -- don't.  That's why most people
use soap to wash grease away.

DB:  Soap works like this.  The molecules in soap look like chains of
atoms.  The tail end of each molecule is somewhat like the grease or oil
you're trying to remove -- it won't dissolve in water.  But the head is
made up of a group of atoms that are attracted to water -- the head of
the soap molecule may carry an electric charge, for example.  When you
squeeze some detergent into a sink full of dirty dishes, a lot of soap
molecules are in the water, all acting in concert.  They point their
tails toward the oil -- and their heads toward the water.  In this way,
the soap forms microscopic droplets that encapsulate the grease.

JB:  So now you have the grease enclosed in droplets that are easy to
wash away.  This is how all soaps work, from shampoo to laundry
detergent to dish detergent.  Ray, thanks for your question.
Send your question to [email protected].  Our show is made possible by
the National Science Foundation.  I'm Joel Block with Deborah Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970225.html


*********************************************************
Wednesday,  February 26, 1997
THE END OF EARTH
Without the sun, most Earth species would die.  But life would go on
indefinitely beneath the surface.  We answer a listener's question on
what would happen to earthly life if the sun disappeared -- after this
on Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky for Wednesday, February 26.  Last October on
our show we answered a listener's question about how long Earth would
remain in orbit if the sun disappeared.

DB:  We said that -- if the sun disappeared -- Earth would quickly head
out in a straight line into space.  Then, people wanted to know, how
long would it take Earth to lose its heat -- and how quickly would life
on our planet come to an end?

JB:  Without the sun, surface temperatures on Earth would plummet to
tens of degrees below zero in a matter of weeks to months.  Lack of
warmth and light would devastate vegetation.  The food chain would
crumple and, even if they could keep warm enough, most earthly species
would quickly face mass starvation.

DB:  Meanwhile, though, life beneath Earth's surface would be largely
oblivious to the apocalypse overhead.  Earth has been slowly cooling
since its formation 4.5 billion years ago -- and our planet's interior
would remain warm for billions of years more.  Earth's core is a
storehouse of energy, supplied largely by the decay of radioactive
elements.  Ultimately, microbes, Earth's earliest inhabitants, would
come to dominate the planet again.  One long-lived species might be the
single-celled archaea.  They already live in total darkness -- and can
survive at temperatures far below freezing.

JB:  We have much more on this subject at our web site.  Learn how to
reach it with an email to [email protected].  With thanks to the
National Science Foundation, we're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970226.html


*********************************************************
Thursday,  February 27, 1997
SPEED OF GRAVITY
Massive objects, such as planets, curve the fabric of space around
themselves as they move through space -- like a bowling ball rolling
across a soft mattress.  More about gravity -- after this on Earth and
Sky.
 _________________________________________________________

DB:  This is Earth and Sky, with a listener's question.

JB:  Nathan Howard writes, "I have always heard about the speed of
light.  But I was wondering if there is such a thing as the speed of
gravity.  How long would it take for one planet to feel the attraction
of another planet?"

DB:  Isaac Newton was the first to explain gravity as a force between
two objects.  He thought that this force traveled instantaneously across
space.  He thought that the Earth immediately "felt" the sun's pull, for
example, and that, if the sun disappeared, Earth would fly off
immediately out of orbit, into the void of space.

JB:  But when Albert Einstein developed his theory of special relativity
in 1905, he concluded that no signal in the universe can travel faster
than the speed of light.  That speed is very fast but not instantaneous
-- about 300,000 kilometers per second.

DB:  So, in Einstein's view, gravity isn't a force that travels out from
a massive object to tug instantly on everything around it.  Instead,
gravity is a "field" that bends space and time.  Today, scientists also
consider gravity to be a force that travels across space at light speed.

JB:  In other words, if the sun disappeared, Earth -- at eight
light-minutes from the sun -- wouldn't know it until eight minutes
later.  Nathan, thanks for your question.  With thanks to the National
Science Foundation, we're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970227.html


*********************************************************
Friday,  February 28, 1997
DINOSAUR FEATHERS
Last October, Chinese dinosaur hunters announced that they'd found the
dinosaur holy grail -- a dinosaur with feathers.  More on the little
dinosaur that has created a big stir -- after this on Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky, on a dinosaur missing link.

DB:  Dinosaur scientists have theorized that birds descended from
dinosaurs.  Many small, two-legged, meat-eating dinosaurs have bird-like
skeletons.  But they also have tails and teeth.  Dinosaurs laid eggs in
nests and cared for their young.  But unrelated species often have
similar habits.  Take dolphins and tuna.  Both swim in the ocean and eat
fish, but tuna are fish and dolphins are mammals.

JB:  Last August, paleontologists digging in north-east China found the
skeleton of a two-legged animal.  Closer examination revealed feather
impressions running down its back.  At first they classified it as an
early bird, but additional analysis made them change their minds.  The
animal wasn't that bird-like.  They named their find Sinosauropteryx,
which means "Chinese feathered lizard."

DB:  The feathers are about a centimeter long.  They're not shaped like
flight feathers, and probably kept the little dinosaur warm.
They may be the missing link between scales and flight feathers.
Sinosauropteryx lived about 130 million years ago -- when birds already
existed.  This dinosaur and the ancestors of modern birds may have had a
common dinosaur ancestor.  If so, then Sinosauropteryx probably closely
resembles the dinosaur species from which the first birds evolved.

JB:  With thanks to the National Science Foundation, we're Byrd and
Block for Earth and Sky.

http://www.earthsky.com/1997/es970228.html


*********************************************************
Saturday,  March 1, 1997
MONTH OF MARCH
For centuries, the month of March was considered the first month of the
year.  We talk about how March became month number three -- and preview
the coming of spring in the northern hemisphere -- after this on Earth
and Sky.
 _________________________________________________________

DB:  I'm Deborah Byrd.

JB:  And I'm Joel Block for Earth and Sky -- Saturday, March 1.  It's
said that Romulus, founder of Rome, decreed that the year would begin in
the month of March.  There were only 10 months in that early Roman
calendar -- March through December.  You might know that names
September, October, November and December stem from Latin roots meaning
"seven, eight, nine, and ten."

DB:  January and February were part of an unnamed winter season.  Around
700 B.C., another Roman leader divided the winter season into two months
and added them to the end of the year.  Later, the Roman state
designated January 1 as New Year's Day.  But long after the fall of the
Roman empire -- throughout the Middle Ages -- people in Western Europe
celebrated their new year around the time of the March equinox.  Even in
the American colonies, people started the year in March -- until just a
couple of decades before the Declaration of Independence.

JB: Spring comes this month to the northern hemisphere.  Our half of the
globe has been leaning  away from the sun.  Now Earth has  moved in
orbit -- so that the sun makes a higher arc across our sky each day --
and the days are perceptibly longer.  We have information on our web
site on how you can see Comet Hale-Bopp.  You can reach us with an email
to [email protected], or go directly to www.earthsky.com.  With thanks
to the National Science Foundation, we're Block and Byrd for Earth and
Sky.


http://www.earthsky.com/1997/es970301.html


*********************************************************
Sunday,  March 2, 1997
HOW TO SEE MARS
The month of March is named for Mars -- the Roman god of war -- and this
March is a good time to see Mars.   We tell you why -- and talk about
how to see the red planet next door  -- after this on Earth and Sky.
 _________________________________________________________

DB:  I'm Deborah Byrd.

JB:  And I'm Joel Block for Earth and Sky for Sunday, March 2.  The
planet to watch this month is Mars.  We'll pass between it and the sun
on the night of March 16, according to clocks here in the western
hemisphere.

DB:  We're closer to Mars now than we've been about two years.  The red
planet appears as a bright reddish light in our sky -- very easy to see.
 It's rising due east right now just about at the end of evening
twilight.  You'll see it low in the east when the sky is fully dark.
Later in the evening, it'll make a slow arc across your southern sky as
seen from the northern hemisphere.  People in the southern hemisphere
see it travel across the northern sky.

JB:  For all of us on Earth, Mars will be rising about five minutes
earlier each day.  It'll be up earlier each evening -- by mid-month,
when we pass between it and the sun, it'll come up when the sun goes
down.  Officially Mars is in front of the constellation Virgo right now,
but it'll be moving into Leo before the month ends.

DB:  Just remember that Mars -- a planet -- doesn't twinkle.   It shines
steadily -- with a distinctly reddish color.   We have information on
our web site on how you can see Comet Hale-Bopp.  You can reach us with
an email to [email protected], or go directly to www.earthsky.com.  With
thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.
Our thanks to the following individuals and institutions who assisted in
the preparation of this script:



http://www.earthsky.com/1997/es970302.html

--------------------------------------------------------------------
You can obtain the text of these mailings, along with educational
materials and Real Audio recordings of our shows via anonymous FTP at:
          ftp://earthsky.com

For more information about Earth & Sky please visit our web site at:
          http://www.earthsky.com

Or email us at:
         [email protected]
--------------------------------------------------------------------

To unsubscribe from this list e-mail to:
          [email protected]

The subject line will be ignored.  In the BODY of the message write:
          UNSUBSCRIBE

Please use this address only for subscribing or unsubscribing.
--------------------------------------------------------------------

All Earth & Sky materials are copyrighted by Byrd & Block Communications
Inc. Permission to use, copy and distribute these materials without fee
is hereby granted, provided that:
    the above copyright notice appear in all copies and
    the materials are not redistributed for profit.

The Earth & Sky logo and "Earth & Sky" are registered trademarks of Byrd
& Block Communications Inc.
###



% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Received: from mail.vbo.dec.com (mail.vbo.dec.com [16.36.208.34]) by vbormc.vbo.dec.com (8.7.3/8.7) with ESMTP id BAA25369 for <[email protected]>; Sat, 22 Feb 1997 01:32:25 +0100
% Received: from server21.digital.fr (server21.digital.fr [193.56.15.21]) by mail.vbo.dec.com (8.7.3/8.7) with ESMTP id BAA24708 for <[email protected]>; Sat, 22 Feb 1997 01:37:09 +0100 (MET)
% Received: from tpoint.net (challenger.tpoint.net [204.29.207.17]) by server21.digital.fr (8.7.5/8.7) with ESMTP id BAA07208 for <[email protected]>; Sat, 22 Feb 1997 01:39:31 +0100 (MET)
% Received:  by tpoint.net (8.8.2/25-eef) id WAA08820; Fri, 21 Feb 1997 22:07:14 GM
% Resent-Date: Fri, 21 Feb 1997 22:07:14 GMT
% X-Sender: [email protected]
% Message-Id: <v03007801af33c5e0235f@[206.160.162.41]>
% Mime-Version: 1.0
% Content-Type: text/plain; charset="us-ascii"
% Date: Fri, 21 Feb 1997 16:10:23 -0600
% To: [email protected]
% From: Angela Lucignani <[email protected]>
% Subject: Earth & Sky : Week beginning 2/24/97
% Resent-Message-ID: <"lX2zB.0.392.wnX3p"@challenger>
% Resent-From: [email protected]
% Reply-To: [email protected]
% X-Mailing-List: <[email protected]> archive/latest/70
% X-Loop: [email protected]
% Precedence: list
% Resent-Sender: [email protected]

From:	VBORMC::"[email protected]" "MAIL-11 Daemon"  3-MAR-1997 19:19:39.21
To:	[email protected]
CC:	
Subj:	Earth & Sky: Week Beginning 3/3/97

*  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

                                      Earth & Sky
                   Scripts for the week beginning 3/3/97

 *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

 Contents:
         What Causes Wind?
         Wormholes
         Albedo
         Alternative Cars
         Why Fat Tastes Good
         Moon Shadow
         Young Moon
  Where to obtain additional information
  Unsubscription
  Copyright Notice

*********************************************************
Monday,  March 3, 1997
WHAT CAUSES WIND?
In the old Saxon language, March was known as "the boisterous month."
Here in the northern hemisphere, March is often windy.  But what causes
wind?  We talk about it -- after this on Earth and Sky

 _________________________________________________________

DB: This is Earth and Sky for Monday, March 3 -- the month that's  said
to "come in like a lion" here in the northern hemisphere.

JB:  And speaking of the windy month, Emily Rosenman -- age eleven --
sent us an email.  She writes, "What causes wind?"

DB: Emily, wind is just the movement of air from one place to another.
You might hear the terms high and low pressure on a local  weathercast.
In a high pressure area, the molecules that make up air are more densely
packed.  Air may be less densely packed in an area of low pressure,
nearby.  Air flows from high pressure to low pressure -- and we
experience that flow as wind.

JB:  The differences in air pressure result from differences in
temperatures across the planet.   In winter, continents are cold, and
oceans are warm.  Earth's poles are cold, and its equator is warm.
Cities can even create warm columns of air that circulate with cooler
air in surrounding rural areas.  Warm air rises -- and cooler air sinks.
  So there are columns of rising and sinking air all over the Earth.

DB:  When a column of warm air rises, it leaves an area of low pressure
underneath it.   This area gets filled by the surrounding atmosphere
rushing in -- and that's wind!   For information on how you can see
Comet Hale-Bopp, send email to [email protected], or go directly to
www.earthsky.com.  With thanks to the National Science Foundation, we're
Block and Byrd for Earth and Sky.


http://www.earthsky.com/1997/es970303.html


*********************************************************
Tuesday,  March 4, 1997
WORMHOLES
A worm might eat a hole in an apple that provides a quick way of getting
from one side of the apple to the other.  We talk about wormholes on the
scale of the universe -- after this on Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky, with an email question from Zalan Alam.

DB:  He writes:  "Are  (wormholes) the opposite of black holes?"

JB:  Zalan, wormholes and black holes aren't opposites exactly -- in
fact, some scientists have postulated that black holes might be
connected by wormholes -- but that's a story for another day.  Both
wormholes and black holes are theoretical constructs -- seen as
distortions in space/time.  One difference is that if you get trapped in
the powerful gravity field of a black hole, you can't ever get out
again!   But, in theory, you could go into a wormhole -- and emerge
again in some other part of the universe.

DB:  A wormhole can be seen as a shortcut connecting two locations in
space.  The laws of physics as we know them don't  forbid the existence
of wormholes.  But the concept has gone up and down in popularity among
scientists -- and it's not very popular at the moment.  The reason it
isn't is that temperatures hot enough to allow for the spontaneous
creation of a large wormhole seemed to be found only in the very early
universe.  It's possible that extremely small wormholes are constantly
appearing and dissolving -- but these would be too small for modern
instruments to detect.

JB:  You can read more about wormholes at our website.  Learn how to
reach it by sending email to [email protected].  Our show is made
possible by the National Science Foundation.  We're Block and Byrd for
Earth and Sky.


http://www.earthsky.com/1997/es970304.html


*********************************************************
Wednesday,  March 5, 1997
ALBEDO
The moon looks bright in our night sky, but it has an albedo far less
than that of the planet Venus.  We talk about the word albedo -- and
tell you how a planet's albedo affects our view of it -- after this on
Earth and Sky.
 _________________________________________________________

DB:  This is Earth and Sky, with a question from a South Carolina
listener.

JB:  Erik Pohl wants to know, "Which planet in our solar system has the
highest albedo  --  and would a mirror have the highest albedo of all
known objects?"

DB:  Astronomers talk about a planet's albedo when speaking of its
brightness.  When light strikes a planet, some is absorbed by the
planet's surface or atmosphere -- and some is reflected.  Albedo is  a
comparison between how much light strikes an object -- and how much is
reflected.

JB:  Venus has the highest albedo of any planet in our solar system.
That's partly why it looks so bright in our sky.  Earth reflects about
30 per cent of the sunlight that hits it, while Venus reflects over 70
per cent.   Venus owes its brilliance to the fact that it's blanketed
with highly reflective clouds.

DB:  Also, Erik, yes, mirrors do have the highest albedos of all known
objects.  But add to that the fact that mirrors reflect light in one
direction only.  And even mirrors aren't perfect reflectors.  A small
amount of light gets trapped by the mirror's surface.   We have
information on our web site on how you can see Comet Hale-Bopp.  Send
email to [email protected], or go directly to www.earthsky.com.  With
thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.


http://www.earthsky.com/1997/es970305.html


*********************************************************
Thursday,  March 6, 1997
ALTERNATIVE CARS
The four hundred million cars on our planet consume much of the world's
energy and produce much of its air pollution.  A listener asks about an
alternative -- after this on Earth and Sky.
 _________________________________________________________

DB:  This is Earth and Sky.  Steve Heidel of Dallas writes, "I recently
heard about a process where cars can run on gas that is 50% water. . .
Can you give me more details?"

JB:  Steve, we talked to experts in the field of alternative cars, and
to representatives from the Society for Automotive Engineers.  No one
had heard of a car that runs on a 50-50 gas/water mixture.  Maybe you're
thinking of a water injection technology -- the water doesn't go in the
fuel tank, but instead in the carburetor.  It's said to  make the engine
more efficient, so it can run on less gasoline.

DB:  But that doesn't seem to be where the excitement -- and the funding
-- is right now.  Electric cars are currently receiving a lot of
attention.  Since the cars themselves don't run on fossil fuels, they
don't emit carbon dioxide.  General Motors has recently begun test
marketing an electric car called the EV-1.  Time will tell if this is an
economically viable alternative to conventional cars.

JB:  Alternative fuels are also being investigated.  Right now, in many
parts of the country, the gasoline you put in your car is about ten per
cent ethanol.  With changes to the engine, your car could run on a
higher concentration of ethanol.  These alternatives may be increasingly
important as gas and oil reserves are depleted -- and atmospheric carbon
dioxide levels rise.  With thanks to the National Science Foundation,
we're Block and Byrd for Earth and Sky.


http://www.earthsky.com/1997/es970306.html


*********************************************************
Friday,  March 7, 1997
WHY FAT TASTES GOOD
(SFX -- dinner bell)  Why do we like fatty foods at dinner?  It's
possible we're naturally attracted to the taste and feel of fatty foods.
We talk about why fat tastes good -- after this on Earth and Sky.

 _________________________________________________________

JB:  This is Earth and Sky, with a listener's question.

DB:  Bennett Kottler writes, "My co-workers and I were speculating on
why fat makes food taste better . . . What do you know about the
relationship of fat to the taste of foods?"

JB:  Bennett, fats help you enjoy the taste of food because they're able
to dissolve flavor and odor chemicals.  These chemicals are then
released into the air by the heat of cooking. (SFX -- bacon frying)
That's why you can taste sizzling bacon even before you eat it --
because some of the flavor molecules are already in your nose and mouth.

DB:  Fatty foods also have a special "mouth feel."  Chocolate mousse,
custard, and peanut butter all melt at body temperature. When chocolate
melts in your mouth, it creates a smooth, full, coating sensation that
most people would agree is pleasant.

JB:  Plus our bodies absorb fatty foods at a slower pace.  Fat makes us
feel full.  And when we feel full, our brains trigger the release of
hormones that also make us feel relaxed and content. The close tie
between fat, flavor, fullness, and happiness might be an evolutionary
adaptation.  In the past, it might have helped protect the body against
starvation and exhaustion.  Bennett, thanks for your question.  And
thanks to the National Science Foundation for making our show possible.
We're Block and Byrd for Earth and Sky.


http://www.earthsky.com/1997/es970307.html


*********************************************************
Saturday,  March 8, 1997
MOON SHADOW
During today's total eclipse of the sun, the moon's shadow sweeps across
Earth's surface.  We talk about what this shadow would look like from
the moon -- after this on Earth and Sky.

 _________________________________________________________


DB:  This is Earth and Sky for Saturday, March 8 -- with a question from
a Tennesee listener.

Tape:  "Hi, this is Tom Burns. . . . My question for Earth and Sky is .
. . What does Earth look like from the moon during a total eclipse of
the sun, when the moon passes right directly between the sun and Earth.
Does the moon shadow form a darkened full circle on the lighted face of
the Earth?"

JB:  Definitely it does, Tom!   It's when you're lucky enough to be  in
a place where the moon's shadow falls that you see a total eclipse.

DB:  The moon's shadow on Earth's surface is about 150 kilometers wide
-- about 100 miles wide.  So you could see it from the moon.   Most of
us won't go to the moon -- but you can see another moon's shadow on its
planet.  Jupiter's four largest moon's, the Galilean satellites,
occasionally cast their shadows on Jupiter.  When this happens, if
you're peering through a telescope, you can see a dark circular shadow
on Jupiter's cloudtops.

JB:  The moon's shadow falls on Earth today -- in a total eclipse of the
sun -- visible from parts of Mongolia and eastern Siberia.  For those in
the shadow's path, the sky will darken -- and Comet Hale-Bopp will come
into view!   We have information on our web site on how you can see
Hale-Bopp.  Send email to [email protected], or go directly to
www.earthsky.com.  With thanks to the National Science Foundation, we're
Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970308.html


*********************************************************
Sunday,  March 9, 1997
YOUNG MOON
The young moon is returning to the evening sky this week.  We tell you
why you see the slimmest young moons in the spring -- and we'll identify
a planet near tonight's moon -- after this on Earth and Sky.
 _________________________________________________________

JB:  I'm Joel Block.

DB:  And I'm Deborah Byrd for Earth and Sky, Sunday March 9.  If you're
lucky, you might see the young moon tonight in the west after sunset.
It'll appear as a fragile crescent -- maybe with some earthlight shining
on the darkened part of the lunar surface.  This is a good time of year
to see young moons from the northern hemisphere.  From this hemisphere,
the ecliptic -- or path of the sun, moon and planets -- stands nearly
straight up in the evening with respect to the western horizon.  So the
moon's separation from the sun is nearly all straight up above that
horizon.

JB:  According to clocks here in the United States, the moon was new
during the night last night.  So there's a slim chance you'll see a slim
crescent moon tonight.   If you do see it, you might glimpse the planet
Saturn to the moon's upper left.  Your chance of seeing the moon is
greatest the farther west you are.  That's because the moon moves
eastward in orbit around Earth -- and right now it's getting farther
from the sun on the sky's dome with each hour that passes.  Overall the
moon is tough to see on Sunday . . .

DB:  But you'll see the moon easily during the rest of this week.  It'll
be in the evening twilight sky -- higher in the sky each day.  We have
information on our web site on how you can see Comet Hale-Bopp.  You can
reach us with an email to [email protected], or go directly to
www.earthsky.com.  With thanks to the National Science Foundation, we're
Block and Byrd


http://www.earthsky.com/1997/es970309.html

--------------------------------------------------------------------
You can obtain the text of these mailings, along with educational
materials and Real Audio recordings of our shows via anonymous FTP at:
          ftp://earthsky.com

For more information about Earth & Sky please visit our web site at:
          http://www.earthsky.com

Or email us at:
         [email protected]
--------------------------------------------------------------------

To unsubscribe from this list e-mail to:
          [email protected]

The subject line will be ignored.  In the BODY of the message write:
          UNSUBSCRIBE

Please use this address only for subscribing or unsubscribing.
--------------------------------------------------------------------

All Earth & Sky materials are copyrighted by Byrd & Block Communications
Inc. Permission to use, copy and distribute these materials without fee
is hereby granted, provided that:
    the above copyright notice appear in all copies and
    the materials are not redistributed for profit.

The Earth & Sky logo and "Earth & Sky" are registered trademarks of Byrd
& Block Communications Inc.
###



% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Received: from mail.vbo.dec.com (mail.vbo.dec.com [16.36.208.34]) by vbormc.vbo.dec.com (8.7.3/8.7) with ESMTP id UAA00462 for <[email protected]>; Mon, 3 Mar 1997 20:16:08 +0100
% Received: from server21.digital.fr (server21.digital.fr [193.56.15.21]) by mail.vbo.dec.com (8.7.3/8.7) with ESMTP id UAA12735 for <[email protected]>; Mon, 3 Mar 1997 20:20:51 +0100 (MET)
% Received: from tpoint.net (challenger.tpoint.net [204.29.207.17]) by server21.digital.fr (8.7.5/8.7) with ESMTP id TAA03727 for <[email protected]>; Mon, 3 Mar 1997 19:32:35 +0100 (MET)
% Received:  by tpoint.net (8.8.2/25-eef) id PAA14360; Mon, 3 Mar 1997 15:26:42 GM
% Resent-Date: Mon, 3 Mar 1997 15:26:42 GMT
% X-Sender: [email protected]
% Message-Id: <v03007800af3a240d6d5d@[206.160.162.41]>
% Mime-Version: 1.0
% Content-Type: text/plain; charset="us-ascii"
% Date: Mon, 3 Mar 1997 09:29:14 -0600
% To: [email protected]
% From: Angela Lucignani <[email protected]>
% Subject: Earth & Sky: Week Beginning 3/3/97
% Resent-Message-ID: <"Y-WD9.0.0W3.Ysk6p"@challenger>
% Resent-From: [email protected]
% Reply-To: [email protected]
% X-Mailing-List: <[email protected]> archive/latest/71
% X-Loop: [email protected]
% Precedence: list
% Resent-Sender: [email protected]

From:	VBORMC::"[email protected]" "MAIL-11 Daemon"  8-MAR-1997 00:53:39.58
To:	[email protected]
CC:	
Subj:	Earth & Sky:  Week beginning 3/10/97

*  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

                                         Earth & Sky
                     Scripts for the week beginning 3/10/97

 *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

 Contents:
         Night of the Comet
         Gulf Stream
         Why the Wind Howls
         Mars Solstice
         Icebergs in the Sky
         Mars Through a Telescope
         Opposition of Mars
  Where to obtain additional information
  Unsubscription
  Copyright Notice

*********************************************************
Monday,  March 10, 1997
NIGHT OF THE COMET
If you haven't seen Comet Hale-Bopp -- you should!  It's visible after
sunset tonight -- and before sunrise tomorrow.  More about following the
comet all night long -- after this on Earth and Sky.
 _________________________________________________________

DB:  This is Earth and Sky for Monday, March 10.   If you're listening
to us in the northern hemisphere, try looking for Comet Hale-Bopp either
in the evening sky tonight -- or before dawn.

JB:  You'll find the comet low in the northwest about an hour after
sunset.  It's bright -- and it'll look like a fuzzy star.  Tonight, it
lies directly below the constellation Cassiopeia, which many people
recognize as having the shape of a W or M.

DB:  The comet will look hazy -- and you should notice a streak coming
from it. The streak is the comet's gas tail.  It's made of material
boiling off the comet's icy nucleus, thanks to the warmth of our sun.
Under the sun's influence, comet tails grow and stretch for millions of
miles.  If you watch until the comet's head sets, you might see its tail
 remain visible for a little longer.  Then the tail will set, too.

JB:  But if you live north of about 50 degrees latitude -- that's
roughly Calgary, Winnipeg, Frankfurt, or Prague -- you won't see the
comet set at all.  It'll pass directly below Polaris, the north star --
then begin to rise again.  For those who don't live quite so far north,
the comet will reappear in the northeast about 2 a.m. tomorrow.  As dawn
begins, look for Comet Hale-Bopp about a quarter of the way up in the
east.  For more information on how to see Comet Hale-Bopp, visit our web
site at www.earthsky.com.  With thanks to the National Science
Foundation, we're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970310.html


*********************************************************
Tuesday,  March 11, 1997
GULF STREAM
How can an ocean current affect  temperatures over the coasts?  It
happens due to prevailing winds.   We talk about how an ocean current
from the Gulf of Mexico makes parts of Europe warmer -- after this on
Earth and Sky
 _________________________________________________________

DB: I'm Deborah Byrd.

JB:  And I'm Joel Block for Earth and Sky.  Today's question comes from
Katherine Warren in Riverside, California.  Katherine writes, "How does
the Gulf Stream make areas of Europe, such as the cold west coasts of
Ireland and Scotland far more temperate. . .?"

DB: Katherine, the Gulf Stream is a warm ocean current that originates
in the Gulf of Mexico.  High temperatures around the equator heat the
water.  Earth's rotation forces this warm water to move.  It flows first
north along North America, then turns east across the Atlantic Ocean.
As it approaches Europe, the Gulf Stream turns into what's called the
North Atlantic Drift current.

JB:  From approximately thirty to sixty degrees North latitude - an area
that includes most of North America, Europe and much of Asia,  Earth's
prevailing winds blow from west to east.   As the winds move across the
warm North Atlantic Drift and onto the coast of Ireland and Scotland,
the air is warmed.

DB: The reverse can also be true.  The Pacific Ocean's California
current is cold, and the prevailing winds blow onshore.  This keeps the
immediate coastline of California cool.  That's our show for today.
Check our web site for information on how you can see Comet Hale-Bopp.
Send email to [email protected], or go directly to www.earthsky.com.
With thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970311.html


*********************************************************
Wednesday,  March 12, 1997
WHY THE WIND HOWLS
Up next, we answer a question from a listener in Washington about what
makes the wind howl sometimes. Whirling winds -- and howling winds --
after this on Earth and Sky.
 _________________________________________________________

JB: This is Earth and Sky with a question from Jane Doyle in Kennewick,
Washington.

Tape:  "My question is about the wind.   Sometimes when the wind is
strong, it howls, and other times it doesn't.   I was wondering what
makes the wind howl?"

DB: Jane, in some ways, wind can be like a swiftly flowing river.  You
know how whirlpools can form in river water due to rocks or other
obstacles in the way.  The same thing can happen with wind.  Whirlpools
can form when the wind passes an object -- such as a chimney or building
or tree -- and the object disturbs the wind's flow.   Sometimes
whirlpools form in wind without any objects in the way.  There may
simply be instabilities in the wind itself.  In either case, these
whirlpools are what cause the wind to howl.

JB:  Inside a whirlpool of wind, the air expands slightly -- the air
pressure gets lower -- and this expansion of air creates a sort of pulse
of pressure.  When a series of pulses hits the ear, it produces the
howling sound we hear.  So you hear wind howl when there are whirling
eddies in the wind (SFX - howling wind).  These whirlpools set off a
domino effect of vibrations -- which travel through the air until  they
hit your ear drum -- and make it vibrate.  And that's when you hear the
wind howl.  That's our show for today.  It's made possible by the
National Science Foundation.  Send your Earth or sky question by email
to [email protected].  We're Block and Byrd for Earth and Sky.


http://www.earthsky.com/1997/es970312.html


*********************************************************
Thursday,  March 13, 1997
MARS SOLSTICE
Today . . . summer solstice on the planet Mars.  What the solstice on
Mars means for this neighboring planet -- and some similarities between
our world and the world next door -- after this on Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky for Thursday, March 13 -- on today's summer
solstice . . . on the planet Mars.

DB:  In the month of June here on Earth, we in the northern hemisphere
see the sun make a high arc across the sky each day.   Our summer
solstice -- around June 21 -- marks the northernmost path of the sun for
the year.

JB:  If you were standing on Mars today, you'd see the sun take its
northernmost path for the martian year.   Today is the summer solstice
for the martian northern hemisphere.

DB:  Both Earth and Mars  are tilted on their axes by nearly the same
amount.  Earth is tilted by about 23-and-a-half degrees.  Mars is tilted
by more like 25 degrees.  Earth's axial tilt creates the four seasons on
our world -- it brings the sun's light and warmth more directly to one
hemisphere for part of every year.  Mars has four seasons, too -- but
since Mars takes two years to orbit the sun, each of the martian seasons
lasts six months.

JB:  This happens to be an excellent time to see Mars in the night sky.
 You might recognize it as the very bright reddish object -- ascending
in the east each evening.  By the way, you might also want to see Comet
Hale-Bopp -- and we have information that can help you do that.  Send
email to [email protected] -- or go directly to www.earthsky.com.  With
thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970313.html


*********************************************************
Friday,  March 14, 1997
ICEBERGS IN THE SKY
A listener wrote to tell us about an illusion he saw -- that of icebergs
floating in the sky.   How conditions came together to create this
special kind of mirage -- after this on Earth and Sky.
 _________________________________________________________

JB: This is Earth and Sky with a question from Bob Broussard.

DB:  He writes, "Last (summer) while (in) my sailboat . . . in southeast
Alaska I could see what appeared to be icebergs floating in the sky.
They appeared . . . about 15 miles away. Icebergs were present, and the
weather was calm, clear and warm.  What (makes) this occur?"

JB: Bob, you saw what's called a superior mirage -- the kind of mirage
that gives the illusion that an object is above its actual position.
We see any object by virtue of the fact that rays of light are
reflecting from it.  When you see a mirage, the light rays have been
first reflected -- and then bent by the atmosphere.

DB:  A superior mirage happens where there's a layer of cold air below,
and warm air above. Cold air is denser than warm air,  but when the
density is very different and the change happens over a very short
distance, then you might see this sort of mirage.  Bob, it makes sense
that you saw it while boating in Alaska during the summer.  These sorts
of mirages are common in that part of the world around then.  The air
around the icebergs, near the water, would have been very cool -- in
contrast to the warmer air above.   The result -- flying icebergs.

JB:  That's our show -- with a warm hello today to affiliate station
WNYC in New York.  If you hear us on WNYC, let us know!  Send email to
[email protected].  We're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970314.html


*********************************************************
Saturday,  March 15, 1997
MARS THROUGH A TELESCOPE
If you had a telescope, you'd want to turn it on the planet Mars in the
coming weeks.   Why this is a great time to see Mars -- after this on
Earth and Sky.
 _________________________________________________________

DB:  This is Earth and Sky -- Saturday, March 15.   Tomorrow, our planet
Earth flies between Mars and the sun.

JB:  This is the martian opposition.  Right now, Mars is located
generally opposite the sun in our sky -- and it's generally closest to
Earth. The distance of Mars at opposition varies, and this is not an
especially close one.  But this is a good time to see Mars.  It's rising
in the east as the sun is going down.  It's highest in the sky around
midnight.   You might be able to recognize Mars just by looking for a
bright reddish object -- in the east in the evening hours.

DB:  If you turned a telescope on any of the stars in Mars' vicinity,
they'd still look . . .well. . .starlike.  But Mars shows a small
reddish disk through a telescope.  Dark markings on the disk change over
time, as the martian seasons pass -- as winds blow and sand shifts from
place to place.  Major dust storms sometimes kick up on Mars and obscure
large sections of the planet.  But these storms tend to come around the
time Mars is closest to the sun.  Mars was farthest from the sun in
January -- so dust storms are unlikely now.

JB:  The martian north polar ice cap is now leaning in our direction.
It can be easily visible through telescopes -- but it'll have shrunk to
a very small size around now.  That's because it's now high summer in
the northern hemisphere of Mars.  With thanks to the National Science
Foundation, we're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970315.html


*********************************************************
Sunday,  March 16, 1997
OPPOSITION OF MARS
Tonight the planet Mars rises in the east as the sun is going down.  We
talk about today's opposition of Mars -- about why this isn't an
especially favorable opposition -- after this on Earth and Sky.
 _________________________________________________________

DB:  This is Earth and Sky for Sunday, March 16.   Today our planet
Earth is flying between Mars and the sun.

JB:  This is the martian opposition, when Mars appears opposite the sun
in our sky.  Oppositions of Mars come about every two years -- but the
best ones come when we fly between Mars and the sun around the same time
Mars is closest to the sun in its two-year orbit.  Then the red planet
is as near the sun as it can be --  and we're between it and the sun --
so Mars is as near as it can be to us.   The closest possible distance
between our two worlds is about 55 million kilometers.  At this
opposition, Earth and Mars are separated by nearly 95 million
kilometers.

DB:  Mars was farthest from the sun at the end of January.  As you might
have guessed -- in an orderly universe -- there's a regular cycle for
favorable oppositions of Mars.  The closest ones come about every 17
years.  The last one was in 1988.  That year, Mars got brighter suddenly
and dramatically over just a few weeks.  It looked like a dot of flame
in the night sky.

JB:  The next really close martian oppositions will come after the turn
of the century.   But you can see Mars tonight.   It rises when the sun
sets -- and it's the  bright reddish object in the east each evening.
With thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970316.html

--------------------------------------------------------------------
You can obtain the text of these mailings, along with educational
materials and Real Audio recordings of our shows via anonymous FTP at:
          ftp://earthsky.com

For more information about Earth & Sky please visit our web site at:
          http://www.earthsky.com

Or email us at:
         [email protected]
--------------------------------------------------------------------

To unsubscribe from this list e-mail to:
          [email protected]

The subject line will be ignored.  In the BODY of the message write:
          UNSUBSCRIBE

Please use this address only for subscribing or unsubscribing.
--------------------------------------------------------------------

All Earth & Sky materials are copyrighted by Byrd & Block Communications
Inc. Permission to use, copy and distribute these materials without fee
is hereby granted, provided that:
    the above copyright notice appear in all copies and
    the materials are not redistributed for profit.

The Earth & Sky logo and "Earth & Sky" are registered trademarks of Byrd
& Block Communications Inc.
###



% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Received: from mail.vbo.dec.com (mail.vbo.dec.com [16.36.208.34]) by vbormc.vbo.dec.com (8.7.3/8.7) with ESMTP id BAA15210 for <[email protected]>; Sat, 8 Mar 1997 01:50:32 +0100
% Received: from server21.digital.fr (server21.digital.fr [193.56.15.21]) by mail.vbo.dec.com (8.7.3/8.7) with ESMTP id BAA12018 for <[email protected]>; Sat, 8 Mar 1997 01:55:14 +0100 (MET)
% Received: from tpoint.net (challenger.tpoint.net [204.29.207.17]) by server21.digital.fr (8.7.5/8.7) with ESMTP id BAA14630 for <[email protected]>; Sat, 8 Mar 1997 01:57:53 +0100 (MET)
% Received:  by tpoint.net (8.8.2/25-eef) id XAA04222; Fri, 7 Mar 1997 23:09:07 GM
% Resent-Date: Fri, 7 Mar 1997 23:09:07 GMT
% X-Sender: [email protected]
% Message-Id: <v0300780aaf465056d0a1@[206.160.162.41]>
% Mime-Version: 1.0
% Content-Type: text/plain; charset="us-ascii"
% Date: Fri, 7 Mar 1997 17:12:07 -0600
% To: [email protected]
% From: Angela Lucignani <[email protected]>
% Subject:  Earth & Sky:  Week beginning 3/10/97
% Resent-Message-ID: <"8wxLH2.0.Z11.20A8p"@challenger>
% Resent-From: [email protected]
% Reply-To: [email protected]
% X-Mailing-List: <[email protected]> archive/latest/72
% X-Loop: [email protected]
% Precedence: list
% Resent-Sender: [email protected]

From:	VBORMC::"[email protected]" "MAIL-11 Daemon" 15-MAR-1997 00:53:32.42
To:	[email protected]
CC:	
Subj:	Earth & Sky: Week Beginning 3/17/97

<bigger><bigger>*  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *
 *  *  *  *  *


                            Earth & Sky

               Scripts for the Week Beginning 3/17/97


 *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  * 
*


 Contents:

        How Wide Is Lightning?	

        Fishing in Lightning

        Comet Tails

        The March Equinox

        Hairy Star

        Moon and Mars

        Partial Lunar Eclipse

  Where to obtain additional information

  Unsubscription

  Copyright Notice


*********************************************************

Monday,  March 17, 1997

HOW WIDE IS LIGHTNING?

Lightning is five times as hot as the surface of the sun -- but only
for

a few tenths of a second at a time.  We give answers to some
listeners'

questions about lightning -- after this on Earth and Sky.

 _________________________________________________________


DB:  This is Earth and Sky for Monday, March 17, with a weather

question.  Several listeners have asked, "How wide is lightning?"


JB:  A lightning flash is caused by an electric current in the sky --

maybe running between clouds -- or between a cloud and the ground.  

Lightning generally ranges in length from about a hundred meters -- to

several kilometers.  In extreme cases, lightning flashes have been

measured at about 30 kilometers -- or 20 miles -- in length.  But

lightning is much thinner than it is long.  Lightning is surrounded by
a

glow called a corona -- that can measure some half a dozen meters --

maybe ten to twenty feet -- in diameter.  Meanwhile, the lightning

itself is only a couple of centimeters in diameter -- about as big

around as a pencil.  


DB:  Other listeners want to know, "what is heat lightning?"   It's

lightning you can see -- but not hear -- usually because the lightning

flash is far away.  Light travels about a hundred thousand times
faster

than sound, so, for distant lightning, the light reaches us well
before

the sound.  What's more, the sound dissipates much more quickly than
the

light.  So depending on wind direction and other atmospheric
conditions,

the thunder may never arrive.  The skies overhead may be clear -- and

that's why it can seem as though heat lightning is coming out of the

blue.  That's our show for today.  We produce it with a grant from the

National Science Foundation.  I'm Deborah Byrd with Joel Block for
Earth

and Sky.


http://www.earthsky.com/1997/es970317.html



*********************************************************

Tuesday,  March 18, 1997

FISHING IN LIGHTNING

Lightning travels several kilometers from clouds to the ground.  Each

bolt unleashes enough energy to power a million light bulbs.  We talk

about how to be safe in a lightning storm -- after this on Earth and

Sky.


 _________________________________________________________


DB:  This is Earth and Sky, with a question from Robert Lane.


JB:  He writes,  "I am an avid fly fisherman and frequently find
myself

on the river in a raft during lightning storms.  We always have a
debate

at these times on where we are safest . . . pulling into shore or

staying on the water. . . Since I have heard one is safe in a car when

lightning strikes I wonder if the raft floating on the water is

insulated ... and therefore the safest place to be."


DB:  Robert, the scientists we spoke with all agreed that -- under no

circumstances -- should you remain on the water during a lightning

storm.  If your raft is made of rubber, you may feel that you're well

insulated, but don't kid yourself.  Typical lightning flashes travel
10

to 15 kilometers and can deliver as much as 100 thousand amps of

current.  In comparison, a toaster uses about 10 amps of current.  If

lightning strikes the water near you, it will have no trouble
traveling

through a few extra centimeters of rubber.


JB:  So, if you're on the water and a thunderstorm approaches, get to

the shore and seek shelter on land.  Try a building or car.  If
neither

are available, look for a cave, cliff wall, or a group of trees. 
Never

take shelter under an isolated tree --it's also a good target for

lightning.  We have information on how you can see Comet Hale-Bopp. 
To

receive it, send email to [email protected] -- or go directly to

www.earthsky.com.  With thanks to the National Science Foundation, I'm

Joel Block with Deborah Byrd for Earth and Sky.


http://www.earthsky.com/1997/es970318.html



*********************************************************

Wednesday,  March 19, 1997

COMET TAILS

Comet Hale-Bopp has arrived in the evening sky -- and it should be
easy

for you to find and see tonight!  We'll tell you how to locate it --
and

what you'll see when you do -- after this on Earth and Sky.


 _________________________________________________________


DB:  This is Earth and Sky -- Wednesday, March 19. Comet Hale-Bopp is

here, and it's visible in the sky tonight.  


JB:  If you're hearing us in the northern hemisphere, just go outside

about an hour after sunset. Pick a place where you can look toward the

northwest without trees or buildings being in the way.  The comet will

look distinctly different from anything else up there-- like a fuzzy

star -- hopefully with a long tail pointing away from the direction

where the sun set earlier.


DB:  The tail is produced by gases boiling off the icy nucleus or core

of Hale-Bopp.  A tail isn't a permanent feature of a comet -- comet

tails form only when comets are near the sun.  And Hale-Bopp is near
the

sun!  Its closest approach in the last several thousand years will
come

on April 1.  Then Hale-Bopp will be 137 million kilometers -- about 85

million miles -- from the sun. 


JB:  Hale-Bopp is bright.  But if you live under the glare of city

lights, you might want binoculars to see it better.  In the coming
week,

the comet will pass another fuzzy sky object -- the Great Galaxy in

Andromeda.  Maybe the comet can help you see the galaxy.  Meanwhile,
if

you live south of the equator, your best chance to see Hale-Bopp comes

in about a month.  For more information on how to see Comet Hale-Bopp,

send email to [email protected], or go to www.earthsky.com.  With
thanks

to the National Science Foundation, we're Block and Byrd for Earth and

Sky.


http://www.earthsky.com/1997/es970319.html



*********************************************************

Thursday,  March 20, 1997

THE MARCH EQUINOX

Tonight Mars ascends in the east after sunset -- while Comet Hale-Bopp

appears as a ghostly apparition in the northwest.  A comet and a
planet

on this day of the March equinox -- after this on Earth and Sky.

 _________________________________________________________


JB:  This is Earth and Sky for Thursday, March 20.  Today the sun

crosses the celestial equator, moving from south to north.   This

sun-crossing comes today at 9:55 a.m. Eastern Standard Time.


DB:   The March equinox marks the first day of autumn for people south

of the equator -- and spring for us on the northern half of the globe. 


There are some pretty interesting events happening at this equinox. 
For

one thing, we passed between the sun and the planet Mars on Sunday --

and today Mars is closer to Earth than it has been for the past two

years.  Mars is a little closer today than it was on Sunday -- the day

we passed between it and the sun -- because Mars was farthest from the

sun at the end of January.  It's now edging a little closer to the sun

each day -- and that motion of Mars in orbit has brought it closer to
us

today.  Today Earth and Mars are separated by about 91 million

kilometers -- that's about 55 million miles.  You can see Mars after
the

sun goes down -- as a bright reddish light in the east.


JB:  Around that same time of day -- in the hour or so after sunset --

turn away from Mars and gaze toward the northwestern sky.  You might

catch of glimpse of the comet everyone is talking about -- Comet

Hale-Bopp.  For information on how to see Hale-Bopp, send email to

[email protected], or go directly to www.earthsky.com.  With thanks to

the National Science Foundation, we're Block and Byrd for Earth and
Sky.


http://www.earthsky.com/1997/es970320.html



*********************************************************

Friday,  March 21, 1997

HAIRY STAR

The nucleus or core of a comet may be only a few kilometers across --

while a comet's tail may stretch millions of kilometers in length.  

More on Comet Hale-Bopp -- after this on Earth and Sky.

 _________________________________________________________


DB:  This is Earth and Sky -- Friday, March 21. From the northern

hemisphere, look for Comet Hale-Bopp in the evening now. 


JB:   It's now at its best -- still approaching the sun -- getting

brighter all the time.  To see it, you need a clear view of the

northwest in the evening.  Hale-Bopp currently lies just below what
may

be a familiar shape to some -- the W-shaped constellation Cassiopeia. 

If buildings or trees block the horizon, try a park or schoolyard --

even a rooftop.  You'll see the comet better if you don't stand under
a

streetlight -- instead, step into the shade of a building.


DB:  The word comet comes from a Greek word meaning "hairy star."  The

head of a comet might appear as a bright, star-like center -- but that

center would be surrounded by a patch of haze.  The bright core, by
the

way, is the site of comet's nucleus -- it's a chunk of ice and dirt

about as big as a small city.


JB:  When sunlight hits the ice in the nucleus or core of the comet,
it

turns the ice to gas.  This gas makes the fuzzy glow we see when we
look

at Hale-Bopp.  And because more gas is coming off the nucleus all the

time, the excess streams away, sometimes for millions of kilometers --

in what we know as the comet's tail.  You should be able to see the
tail

of Hale-Bopp -- pointing away from the place where the sun set earlier.


For a special article on Hale-Bopp, check out our web page at

www.earthsky.com.  With thanks to the National Science Foundation,
we're

Block and Byrd for Earth and Sky.


http://www.earthsky.com/1997/es970321.html



*********************************************************

Saturday,  March 22, 1997

MOON AND MARS

The moon is nearly full in the evening sky, and it's near the planet

Mars tonight.  Moon and Mars-watching -- and more on Comet Hale-Bopp
--

after this on Earth and Sky.


 _________________________________________________________


DB:  I'm Deborah Byrd


JB:  And I'm Joel Block for Earth and Sky -- Saturday, March 22. 
We're

coming up on another full moon -- and a partial eclipse of the moon

visible from most of the Americas -- except the northwest.


DB:  The moon is full tomorrow night.  That's when the partial lunar

eclipse will take place.  Tomorrow night, at mid-eclipse, the moon
will

be 92 per cent covered by the shadow of the Earth.  Tonight, though, 

you can see something else --  that'll enhance your enjoyment of

tomorrow's eclipse. You can look outside this evening and identify
Mars

near the moon.   It makes sense that Mars would appear near this
month's

nearly full moon.  Mars just passed opposition, when Earth flew
between

the red planet and the sun -- and Mars appeared opposite the sun from

Earth.  Mars was at opposition a week ago.


JB:  A full moon is always opposite the sun.  That's why we see it as

full -- right now, its fully lighted hemisphere faces our way.  So
right

now the moon is generally opposite the sun -- Mars is also generally

opposite the sun -- and so Mars appears near the moon tonight.  And if

you see Mars and the moon tonight, be sure to look for Mars again

tomorrow night -- when the moon undergoes a partial eclipse.


DB:  By the way, we have information on Comet Hale-Bopp at our site on

the World Wide Web.  Go to www.earthsky.com -- or send email to

[email protected].  With thanks to the National Science Foundation,

we're Block and Byrd for Earth and Sky.  


http://www.earthsky.com/1997/es970322.html



*********************************************************

Sunday,  March 23, 1997

PARTIAL LUNAR ECLIPSE   

The Earth's shadow sweeps across the moon's face this evening in what

one hemisphere of Earth sees as a partial eclipse of the moon.  More
on

what to expect -- after this on Earth and Sky.


 _________________________________________________________


DB:  This is Earth and Sky, Sunday, March 23.   An eclipse of the sun

takes place when the moon moves directly in front of the sun and blots

it from view.  


JB:  But a lunar eclipse is a less substantial event -- a play of

shadows and light.  A lunar eclipse takes place when Earth's shadow

falls on the moon -- which it does tonight for the Americas -- all but

the extreme northwestern part. 


DB:  You don't have to do anything special to get ready for tonight's

partial eclipse of the moon.  Binoculars or a telescope will enhance
the

view -- but you don't really need them.  You might want to scout out a

good spot to watch this partial eclipse.   Hilltops and rooftops are

especially good -- but anyplace will do that provides a clear view of

the sky.


JB: Try to watch the eclipse from the time it starts until the moon
goes

as far as it will into Earth's shadow.  If you watch from the
beginning

until mid-eclipse, you'll be watching for about an hour and a half. 

Tonight's partial lunar eclipse starts at the exact same moment for

everyone -- so the time of the eclipse on your clock will depend on
your

time zone.  Look for a dark notch in one edge of the moon -- it'll be

9:57 p.m. in Eastern Standard Time -- on Sunday.  At mid-eclipse --

about 90 minutes later -- 92% of the moon will be in shadow.   Of

course, Comet Hale-Bopp is up there tonight as well -- and we have

information about it we can send you.


DB:  Just send email to [email protected].  With thanks to the
National

Science Foundation, we're Block and Byrd for Earth and Sky.


http://www.earthsky.com/1997/es970323.html


--------------------------------------------------------------------

You can obtain the text of these mailings, along with educational

materials and Real Audio recordings of our shows via anonymous FTP at:

          ftp://earthsky.com

  

For more information about Earth & Sky please visit our web site at:

          http://www.earthsky.com


Or email us at:

         [email protected]

--------------------------------------------------------------------


To unsubscribe from this list e-mail to:

          [email protected]


The subject line will be ignored.  In the BODY of the message write:

          UNSUBSCRIBE


Please use this address only for subscribing or unsubscribing.

--------------------------------------------------------------------


All Earth & Sky materials are copyrighted by Byrd & Block
Communications

Inc. Permission to use, copy and distribute these materials without
fee

is hereby granted, provided that: 

    the above copyright notice appear in all copies and 

    the materials are not redistributed for profit. 


The Earth & Sky logo and "Earth & Sky" are registered trademarks of
Byrd

& Block Communications Inc. 

###

</bigger></bigger>



% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Received: from mail.vbo.dec.com (mail.vbo.dec.com [16.36.208.34]) by vbormc.vbo.dec.com (8.7.3/8.7) with ESMTP id BAA19686 for <[email protected]>; Sat, 15 Mar 1997 01:50:22 +0100
% Received: from server21.digital.fr (server21.digital.fr [193.56.15.21]) by mail.vbo.dec.com (8.7.3/8.7) with ESMTP id BAA28734 for <[email protected]>; Sat, 15 Mar 1997 01:55:04 +0100 (MET)
% Received: from tpoint.net (challenger.tpoint.net [204.29.207.17]) by server21.digital.fr (8.7.5/8.7) with ESMTP id BAA13307 for <[email protected]>; Sat, 15 Mar 1997 01:57:52 +0100 (MET)
% Received:  by tpoint.net (8.8.2/25-eef) id WAA08084; Fri, 14 Mar 1997 22:46:43 GM
% Resent-Date: Fri, 14 Mar 1997 22:46:43 GMT
% X-Sender: [email protected]
% Message-Id: <v03007800af4f84b44749@[206.160.162.42]>
% Mime-Version: 1.0
% Content-Type: text/enriched; charset="us-ascii"
% Date: Fri, 14 Mar 1997 16:47:32 -0600
% To: [email protected]
% From: Lin Parafin <[email protected]>
% Subject: Earth & Sky: Week Beginning 3/17/97
% Resent-Message-ID: <"AhJdA2.0.tz1.0LTAp"@challenger>
% Resent-From: [email protected]
% Reply-To: [email protected]
% X-Mailing-List: <[email protected]> archive/latest/73
% X-Loop: [email protected]
% Precedence: list
% Resent-Sender: [email protected]

From:	VBORMC::"[email protected]" "MAIL-11 Daemon" 21-MAR-1997 23:41:46.26
To:	[email protected]
CC:	
Subj:	Earth & Sky : Week Beginning 3/24/97

*  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

                                    Earth & Sky
                Scripts for the Week Beginning 3/24/97

 *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

Contents:
    Comet Meets Galaxy
    Observing Hale-Bopp
    Mission to Asteroid McAuliffe
    Perihelion Advance
    Comet in the Kitchen
    Mudboils
    Why Lakes Turn Over
  Where to obtain additional information
  Unsubscription
  Copyright Notice

*********************************************************
Monday,  March 24, 1997
COMET MEETS GALAXY
Tonight and tomorrow night Comet Hale-Bopp passes near a famous celestial
landmark, the Andromeda Galaxy.  When comet meets galaxy -- after this on Earth
and Sky.

 _________________________________________________________

JB:  This is Earth and Sky -- Monday, March 24.  In the evening sky tonight and
tomorrow night, Comet Hale-Bopp is sweeping near the most distant object
visible
to the naked eye -- the Great Galaxy in the constellation Andromeda.

DB:  You can see the comet and the Andromeda Galaxy after sunset -- in a dark
country sky.  Look for them above the northwestern horizon.  Comet
Hale-Bopp will
appear as a hazy star -- with a long tail pointing up and away from the glow of
twilight.

JB:  The galaxy isn't as easy to spot -- and you really do need a dark sky
to see
it.  The Andromeda Galaxy also looks like a hazy patch -- minus the long comet
tail.   If you have binoculars they'll help you see the galaxy better, even if
you're at a less than totally dark site.  The galaxy lies to the lower left of
the comet.   It's almost as though the comet -- and its tail -- point
downward to
the galaxy.

DB:  Remember when you see the pair that Hale-Bopp is in our own backyard,
cosmically speaking.  It's even closer to the sun than we are at the
moment.  And
although the galaxy looks small in the sky, it's actually similar in size
to our
Milky Way -- an island of several hundred billion stars.  The Andromeda Galaxy
looks small only because we're seeing it across a distance of more than two
million light-years.  That's our show for today.  With thanks to the National
Science Foundation, we're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970324.html


*********************************************************
Tuesday,  March 25, 1997
OBSERVING HALE-BOPP
In the northwestern sky tonight you can find Comet Hale-Bopp.  We'll tell you
more about where to look for this once-in-a-lifetime comet -- and what
you'll see
-- after this on Earth and Sky.
 _________________________________________________________

JB :  This is Earth and Sky for Tuesday, March 25.  An hour after sunset
tonight,
look for a fuzzy "star" in the northwest.  This is Comet Hale-Bopp, the object
you've been hearing so much about.

DB:  A common misconception is that comets "whoosh" across the sky.  (SFX --
whoosh)  They don't.  They're moving in orbit around the sun, just as Earth and
the other planets are, and just as the moon is moving in orbit around Earth.
Much like the moon, a comet can be seen to move from night to night, and even
from hour to hour.  But, as you stand gazing at a comet, it'll appear to
hold as
still in the sky as the sun, moon or stars.

JB:  Also, some people fret that if they've never seen a comet, they might
not be
able to recognize it in the night sky. You don't need to worry about this,
either.  A comet typically resembles a small fuzzy patch of light.  It doesn't
look like an ordinary star!  Comets typically show a bright core and
sometimes an
elongation in some direction.  This elongation is the comet's tail.  Comets
often
produce two tails, one of dust, the other of gas.  The dust tail may be
relatively short, and some show streaks.  The gas tail is typically longer,
straighter, and bluish in color.

DB:  For more on Hale-Bopp, check our Web site at www.earthsky.com.  Or you can
email [email protected]. With thanks to the National Science Foundation,

http://www.earthsky.com/1997/es970325.html


*********************************************************
Wednesday,  March 26, 1997
MISSION TO ASTEROID MCAULIFFE
We talk about a space mission to an asteroid -- this one named for teacher and
astronaut Christa McAuliffe.  More about Deep Space One -- after this on Earth
and Sky.

 _________________________________________________________

JB: This is Earth and Sky.  In July 1998, a rocket will blast off from the
Earth
for a mission called Deep Space One.  Among its destinations -- an asteroid
named
McAuliffe.

DB: The asteroid was named on today's date in the year 1986 for teacher and
astronaut Christa McAuliffe.  It was shortly after the Challenger spacecraft
tragedy that took her life.  Along with thousands of other asteroids, asteroid
McAuliffe orbits the sun between the planets Mars and Jupiter .  The
asteroid is
a couple of kilometers long.

JB:  The Deep Space One mission chose asteroid McAuliffe partly because the
asteroid will be in the right place at the right time.  One goal of the mission
is to probe both an asteroid and a comet -- and McAuliffe falls along the
path to
another target of the spacecraft -- a comet called West-Kohoutek-Ikemura.

DB:  The primary purpose of the Deep Space One mission is to test new
technologies for future missions.  There are thirteen radically new
technological
devices being used for the first time on Deep Space One, including methods of
propulsion, communication, and data gathering.  The mission will  use a form of
artifical intelligence to plan its own activities.  Onboard computers will
combine information about mission objectives and the spacecraft's current
conditions to decide what to do next.

JB:  Our show is made possible by the National Science Foundation.  We're Block
and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970326.html


*********************************************************
Thursday,  March 27, 1997
PERIHELION ADVANCE
Today the planet Mercury comes closest to the sun -- and we talk about a
peculiar
feature in the orbit of this innermost planet -- Mercury's perihelion
advance --
after this on Earth and Sky.
 _________________________________________________________

DB:  This is Earth and Sky for Thursday, March 27.  In less than a week, Comet
Hale-Bopp will be at perihelion, the closest point to the sun in an orbit
lasting
several thousand years.

JB:  But today is another object's perihelion -- and this object comes
closest to
the sun in its orbit much more frequently than Comet Hale-Bopp.  Today is
perihelion for the planet Mercury.

DB: Earth's perihelion comes once a year in January.  Then we're a few million
kilometers closer to the sun than at aphelion -- our farthest point from
the sun
in July.  Mercury's perihelion comes even more often than this -- because
Mercury
is the innermost planet, and it takes less time to go around the sun.  Mercury
reaches another perihelion every 88 days.

JB:  Perihelion advance is a peculiar feature of Mercury's orbit -- a
mystery to
astronomers of the past.  Mercury's perihelion advances -- in other words, the
point where Mercury comes closest to the sun moves slightly but steadily over
time.  No one knew why until early in this century, when Albert Einstein
introduced his general theory of relativity.  According to relativity theory,
space curves around massive objects, such as our sun.  Mercury is the innermost
planet, so it's most affected by the sun's curved space.

DB:  For today, that's our program.  The National Science Foundation makes it
possible.  We're Block and Byrd for Earth and Sky.


http://www.earthsky.com/1997/es970327.html


*********************************************************
Friday,  March 28, 1997
COMET IN THE KITCHEN
The fate of an ice cube in a frying pan resembles that of a comet nearing the
sun.  More about what happens when nature turns up the heat on a dirty snowball
-- after this on Earth and Sky.
 _________________________________________________________

JB:  This is Earth and Sky -- Friday, March 28.  I'm Joel Block.

DB:  And I'm Deborah Byrd.  Ever watch what happens when you put a piece of ice
in a hot frying pan?  Try it and you'll see that the chunk of ice hisses and
skitters around as the heat turns the ice to steam that flies away.  Then,
after
a few moments, the ice is gone.

JB:  That's kitchen physics, but something similar happens to a comet when it
comes near the sun -- which is what Comet Hale-Bopp is now doing.  The sun is a
lot hotter than any frying pan, but the comet is also a lot farther away.  In
fact, it's only slightly closer to the sun than Earth is right now.

DB:  A comet is a big ball of ice covered with a dark crust.  At the
distance of
Earth's orbit, sunlight can heat a comet's crust hotter than asphalt in the
summer.  But just a few feet under the crust is ice hundreds of degrees below
zero.

JB:  In the evening sky tonight you can see what happens when sunlight goes to
work on the ice in a comet. Look for Hale-Bopp in the northwest an hour after
sunset.  The comet appears as a beautiful hazy patch with its tail pointing
upward away from the place where the sun set.  That's our show for today --
made
possible by the National Science Foundation.  For more information on
Hale-Bopp,
contact our web site at www.earthsky.com -- or send email to
[email protected].
I'm Joel Block with Deborah Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970328.html


*********************************************************
Saturday,  March 29, 1997
MUDBOILS
In the Tully Valley south of Syracuse, New York, you'll find a geological
phenomenon that sounds hot -- but isn't.  We talk about mudboils -- or mud
volcanoes  --  after this on Earth and Sky.

 _________________________________________________________

JB:  This is Earth and Sky.  In glacier-carved Tully Valley -- south of
Syracuse,
New York -- sand, silt, clay and water are bubbling up out of holes in the
ground
(SFX-thick bubbles).

DB:  These mudboils -- or  mud volcanoes -- are nature's pressure release
valves.
Unlike geysers, which also release steam and water pressure generated by
the heat
within Earth,  mudboils are fairly cool.  The water temperature is like
that of a
hillside spring -- about 10 degrees Celsius -- around 50 degrees Fahrenheit.
Artesian pressure creates these particular mudboils.  It stems from the
shape and
composition of the land in the Tully Valley.  On top of the glaciated bedrock
that forms the valley, there's about a hundred-meter layer of  saturated
fine-grained sand and silt.  Resting on top of that are a couple of dozen
meters
of dense clay and silt.  The clay and silt layer confines the sand and
pressurized water beneath it -- and at the same time exerts pressure on it.  So
holes have formed in the clay layer through which pressurized water and
sediment
are released.

JB:  When water and sediment from below come bubbling up out of holes, the sand
quickly settles out and forms cones that look like tiny volcanoes.  The Tully
Valley mudboils may be the only ones in the world that have been active for
over
a hundred years.   With thanks to the National Science Foundation, we're Block
and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970329.html


*********************************************************
Sunday,  March 30, 1997
WHY LAKES TURN OVER
If water were like most other liquids on Earth, many creatures that live in
lakes
today couldn't survive the winter.  Why lakes turn over -- after this on Earth
and Sky.

 _________________________________________________________

DB:  This is Earth and Sky, with a question from Glen Huff.  He writes, "Why do
lakes . . . turn over periodically?"

JB:  Glen, North America's Great Lakes experience what scientists call
"overturning" twice a year -- in the fall and spring.   In the fall, the
surface
of a lake begins to cool down.  Cool water is denser than warmer water --
so you
end up with water on the lake's surface that's more dense than water below.
The
denser surface water sinks.  It's replaced by warmer, less dense water,
which --
once it's on the surface -- proceeds to lose its heat, become more dense
and sink
too.

DB:  This cooling and sinking of water doesn't go on indefinitely.  The entire
lake can reach a temperature of "maximum density" -- about four degrees
centigrade -- 39 degrees Fahrenheit -- not far above freezing.  At this
temperature, the lake stops turning over.  The surface of the lake may then
cool
further and start to freeze.

JB:  In spring, the lake turns over again.  Surface ice melts -- and  the
surface
water becomes more dense again, as it once more approaches four degrees
centigrade -- the temperature of maximum density.   The surface water
sinks, and
the process of overturning proceeds, moving from shallow areas near the
shore to
the center of the lake.   It's only when warmer less dense water floats on
top of
cooler, denser water that the lake becomes thermally stable once again.  With
thanks to the National Science Foundation, we're Block and Byrd for Earth and
Sky.

http://www.earthsky.com/1997/es970330.html

--------------------------------------------------------------------
You can obtain the text of these mailings, along with educational
materials and Real Audio recordings of our shows via anonymous FTP at:
          ftp://earthsky.com

For more information about Earth & Sky please visit our web site at:
          http://www.earthsky.com

Or email us at:
         [email protected]
--------------------------------------------------------------------

To unsubscribe from this list e-mail to:
          [email protected]

The subject line will be ignored.  In the BODY of the message write:
          UNSUBSCRIBE

Please use this address only for subscribing or unsubscribing.
--------------------------------------------------------------------

All Earth & Sky materials are copyrighted by Byrd & Block Communications Inc.
Permission to use, copy and distribute these materials without fee is hereby
granted, provided that:
    the above copyright notice appear in all copies and
    the materials are not redistributed for profit.

The Earth & Sky logo and "Earth & Sky" are registered trademarks of Byrd &
Block
Communications Inc.
###



% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Received: from mail.vbo.dec.com (mail.vbo.dec.com [16.36.208.34]) by vbormc.vbo.dec.com (8.7.3/8.7) with ESMTP id AAA05326 for <[email protected]>; Sat, 22 Mar 1997 00:37:35 +0100
% Received: from server21.digital.fr (server21.digital.fr [193.56.15.21]) by mail.vbo.dec.com (8.7.3/8.7) with ESMTP id AAA01810 for <[email protected]>; Sat, 22 Mar 1997 00:43:10 +0100 (MET)
% Received: from tpoint.net (challenger.tpoint.net [204.29.207.17]) by server21.digital.fr (8.7.5/8.7) with ESMTP id AAA11259 for <[email protected]>; Sat, 22 Mar 1997 00:46:08 +0100 (MET)
% Received:  by tpoint.net (8.8.2/25-eef) id VAA00196; Fri, 21 Mar 1997 21:25:05 GM
% Resent-Date: Fri, 21 Mar 1997 21:25:05 GMT
% X-Sender: [email protected]
% Message-Id: <v03007827af58ac9200d5@[206.160.162.42]>
% Mime-Version: 1.0
% Content-Type: text/plain; charset="us-ascii"
% Date: Fri, 21 Mar 1997 15:25:55 -0600
% To: [email protected]
% From: Angela Lucignani <[email protected]>
% Subject:  Earth & Sky : Week Beginning 3/24/97
% Resent-Message-ID: <"fPnUh3.0.U2.QolCp"@challenger>
% Resent-From: [email protected]
% Reply-To: [email protected]
% X-Mailing-List: <[email protected]> archive/latest/74
% X-Loop: [email protected]
% Precedence: list
% Resent-Sender: [email protected]

From:	VBORMC::"[email protected]" "MAIL-11 Daemon" 28-MAR-1997 22:19:37.81
To:	[email protected]
CC:	
Subj:	Earth & Sky: Week Beginning 3/31/97

*  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

                             Earth & Sky
                 Scripts for the week beginning 3/31/97

 *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *

Contents:
     Hale-Bopp at Perihelion
     Failed Star
     Two Suns
     16 Cygni B
     Habitable Moons
     Mercury
     Saving Daylight
  Where to obtain additional information
  Unsubscription
  Copyright Notice

*********************************************************
Monday,  March 31, 1997
HALE-BOPP AT PERIHELION
Today Comet Hale-Bopp comes closer to the sun than it has been for
several thousand years. The perihelion of Hale-Bopp -- and how you can
see the comet -- after this on Earth and Sky.
_________________________________________________________

DB:  I'm Deborah Byrd.

JB:  And I'm Joel Block for Earth and Sky -- Monday, March 31.  Today,
according to calendars in the western hemisphere, Comet Hale-Bopp
reaches perihelion -- its closest point to the sun in its orbit.   Today
the comet passes at a distance of 137 million kilometers -- 85 million
miles -- from the sun that binds it in orbit.  It's now about  202
million kilometers -- about 125 million miles --from Earth.

DB:  Earth takes a year to orbit the sun -- while Hale-Bopp takes
several thousand earthly years to complete a single orbit.   We don't
know how many times this comet has come near the sun, but it's thought
not to be a first-time visitor.  For most of its orbit, Hale-Bopp
travels far from the sun. It's only when the comet is near the sun that
sunlight heats its crust -- and Hale-Bopp sprouts its comet tail.
Scientists believe that about a meter of a comet's surface evaporates on
each passage near the sun.  This means that most comets are good for
only about 100 to 1000 apparitions in Earth's sky.

JB:  The best views of Hale-Bopp for northern hemisphere observers are
happening around now.  Soon after the middle of May, the comet will
vanish into evening twilight for northern hemisphere viewers.  Don't
miss it.  For Hale-Bopp information, email [email protected].  With
thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970331.html


*********************************************************
Tuesday, April 1, 1997
FAILED STAR
Our sun is a thousand times more massive than Jupiter, the largest
planet in our solar system.  And yet you still sometimes hear Jupiter
called a "failed star." More on why -- after this on Earth and Sky.
_________________________________________________________

JB:  This is Earth and Sky for Tuesday, April 1 -- with a question about
the pieces of Comet Shoemaker Levy, which struck the planet Jupiter in
the summer of 1994.   This comes from Mike Patterson in Mississippi.

Tape:  ". . .if those comets were large enough to have ignited the
planet Jupiter -- which some called a failed sun, or a sun that failed
to turn on, what would be the effect of Jupiter being the second sun in
this solar system?"

DB:  Mike, whether or not an object can be a star depends on that
object's mass -- how much matter it contains.  And Jupiter is a long way
from being a star. You'd have to roll some 80 Jupiters together into a
ball, for it to have enough mass to ignite and shine even as the puniest
stars do.

JB:  And Comet Shoemaker-Levy -- and all other comets -- are minuscule
in contrast to Jupiter.  You'd have to throw many billions of comets at
Jupiter to supply enough mass to the planet to cause it to ignite as a
star. Clearly, comets won't do the job.  We can't think of anything that
would do it. But let's say Jupiter were born a star -- what effect would
that have on Earth? We answer that question -- tomorrow.  That's today's
show.  If you have an Earth or sky question, send email to
[email protected].  With thanks to the National Science Foundation,  I'm
Joel Block with Deborah Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970401.html


*********************************************************
Wednesday, April 2, 1997
TWO SUNS
An Earth and Sky listener asked, if Jupiter were a star like our sun,
what would happen to the Earth?   We talk about what would happen to
Earth if we lived in a realm of two suns -- after this on Earth and Sky.
_________________________________________________________

DB:  This is Earth and Sky for Wednesday, April 2, on what would happen
to Earth if Jupiter became a star.

JB:  Mike Patterson asked  this question.  And yesterday we said there's
no way we can think of that Jupiter could become a star.  Even the
puniest star has to have at least 80 times Jupiter's mass.

DB:  But suppose Jupiter could be made as massive as our sun -- about a
thousand times as massive as Jupiter is now.  If that happened, the
planet Mars would be in trouble.  Positioned about midway between suns
of equal mass, Mars would be yanked from its orbit in a gravitational
tug-of-war.   Earth would continue moving around the sun, but our orbit
would become much more elliptical, or oval in shape.  What's more, our
cycle of day and night be would profoundly altered. Right now, Jupiter
is rising just before sunup.  So, if Jupiter were a star, it would rise
as a slightly fainter sun, some hours before the regular sunrise.   As
Jupiter and the sun orbited their common center of gravity, our
day/night pattern would shift in complicated ways.  Some days would have
no night at all.

JB:  Now consider what would have happened, billions of years ago, if
Jupiter had been born  a star.  In that case, the gravitational effect
of two suns on the developing planets would have been very important --
and it's likely that Mercury, Venus, Earth, and Mars never would have
formed.  With thanks to the National Science Foundation, we're Block and
Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970402.html


*********************************************************
Thursday, April 3, 1997
16 CYGNI B
Astronomers once thought that planets would be less likely to exist in
multiple star systems.  But a recent discovery has proven them wrong.
More about a weird new solar system -- after this on Earth and Sky.
_________________________________________________________

JB:  This is Earth and Sky for Thursday, April 3 on the discovery of a
planet in a multiple star system.

DB:  Recently, astronomers have found a dozen or so large planet-like
objects in orbit around sun-like stars.  But several aspects of this
recent discovery are forcing astronomers to question their ideas about
how planets form.  The discovery was announced last fall.  The new
planet is orbiting a star known as 16 Cygni B.  This star has a mass and
atmosphere nearly identical to our sun's.

JB:  But 16 Cygni B is not a single star.  It orbits a common center of
gravity with 16 Cygni A, located  about 100 billion kilometers away.   A
third, smaller star, lies about twice that far from the first two.  This
is the first planet to be found in a multiple star system.

DB:  The newly discovered planet is only slightly more massive than
Jupiter -- about one and a half times as massive.  Its orbit is
extremely elongated -- like a circle that someone sat down on -- more
like the orbits of comets in our solar system than like the planets we
know. This strange orbit is probably due to the gravitational interplay
among the three stars and the planet.

JB:  A year ago,  astronomers might have predicted that planetary
systems around other stars would be very much like our own solar system.
 But the 16 Cygni B system is already known to be very different.   With
thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970403.html


*********************************************************
Friday,  April 4, 1997
HABITABLE MOONS
In the movie Star Wars, the rebels have a base on a jungle moon of a
giant planet.  Now astronomers have found planets which are candidates
for possibly having habitable moons.  More -- after this on Earth and
Sky.
_________________________________________________________

DB:  I'm Deborah Byrd.

JB:  And I'm Joel Block for Earth and Sky -- Friday, April 4.  Science
fiction writers sometimes set their stories on Earth-like moons of gas
giant planets -- much like our planet Jupiter.  But, until recently,
astronomers assumed that all true large, Jupiter-type planets orbited
far from their stars.  If so, the moons of any actual planets would be
frozen and uninhabitable.

DB:  But since October of 1995, astronomers have found about a dozen
Jupiter-type planets orbiting close to their stars.  In fact, most are
so close that their moons, if they have any moons, must resemble Mercury
-- the scorched planet closest to our sun.

JB:  Only one star -- 16 Cygni B -- is now known to have a large planet
that might receive just enough heat to give it a habitable moon.  On
average, the planet receives about 60 percent as much heat as Earth
does.  But the orbit of this planet is unusual, and the planet receives
22 times more heat when closest to its star than when it's farthest
away.  If there are any moons orbiting this planet, they must have
ferocious weather.

DB:  Astronomers think we may be about a decade away from discovering
moons in other solar systems.   We have more on habitable moons at our
web site. Send email to [email protected], or go to www.earthsky.com.
With thanks to the National Science Foundation, we're Block and Byrd for
Earth and Sky.

http://www.earthsky.com/1997/es970404.html


*********************************************************
Saturday, April 5, 1997
MERCURY
Around now, if you live in the northern hemisphere, you can see the
planet Mercury shining like a tiny beacon in the west after sunset.
More on when, where and how to see Mercury  -- after this on Earth and
Sky.
_________________________________________________________

DB:  I'm Deborah Byrd.

JB:  And I'm Joel Block for Earth and Sky -- Saturday, April 5. Only a
tiny percentage of Earth's population has ever knowingly identified the
planet Mercury.  And yet Mercury isn't hard to see if you know where to
look. Those in the northern hemisphere can see it easily in the hour
after sunset this evening -- if your western sky is clear.

DB:  Mercury is unusually bright -- brighter than most of the stars.
But, unlike some of the other bright planets, you'll never see Mercury
in a truly dark sky. It's always seen either in the west after sunset,
or in the east before sunrise. People in the northern hemisphere will
find Mercury this evening as a bright starry point, very low in the west
after the sun goes down.  From this hemisphere, this is Mercury's best
evening apparition for this year.

JB:  And if you're out there looking for Mercury, be sure to look also
for the comet that's in the news -- Hale-Bopp.  You can see Mercury in a
twilight sky -- but you'll want a wait a bit for the sky to darken more
before Hale-Bopp comes easily into view.  So watch for Mercury -- a
starry point low in the west, shortly after sunset!  And, when the sky
gets a little darker, look for Comet Hale-Bopp in very nearly the same
part of the sky.  To learn more about Hale-Bopp, check our web site, at
www.earthsky.com.  Our show is made possible by the National Science
Foundation.  I'm Joel Block with Deborah Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970405.html


*********************************************************
Sunday,  April 6, 1997
SAVING DAYLIGHT
Any chance you're running late today?  You know, the clocks moved
forward one hour last night.  We talk a bit about why most states change
their clocks on this day -- after this on Earth and Sky.
_________________________________________________________

JB: This is Earth and Sky for Sunday, April 6 -- with a question from
Anne Raybon from Huntington, West Virginia.

DB:  She writes, "Who decides when Daylight Saving Time begins and ends?
It seems like the dates move around."

JB:  Anne, the U.S. Congress decides when we spring forward or fall back
-- through a law known as the Uniform Time Act of 1966.  This law
doesn't require that all states observe Daylight Saving Time, but it
does require that those that do, do so uniformly.

DB:  And, yes -- for states that do participate -- the dates of starting
and ending Daylight Saving Time have moved around a bit since 1966.   In
1974, we had 10 months of Daylight Saving Time.   In 1975, we had eight.
  Congress was experimenting here -- they found that the energy savings
and other benefits weren't as great as expected during the winter months
-- due to increased dark hours in the mornings.  I also recall people
talking about how dark it was in the mornings when children had to leave
for school.

JB:  Since then, there's been one three-week extension to Daylight
Saving Time -- that was in 1987.  Otherwise, most states change their
clocks on the first Sunday in April and the last Sunday in October.  We
have more on this subject at our web site.  Send email to
[email protected] or go directly to www.earthsky.com. With thanks to the
National Science Foundation, we're Block and Byrd for Earth and Sky.

http://www.earthsky.com/1997/es970406.html

--------------------------------------------------------------------
You can obtain the text of these mailings, along with educational
materials and Real Audio recordings of our shows via anonymous FTP at:
          ftp://earthsky.com

For more information about Earth & Sky please visit our web site at:
          http://www.earthsky.com

Or email us at:
         [email protected]
--------------------------------------------------------------------

To unsubscribe from this list e-mail to:
          [email protected]

The subject line will be ignored.  In the BODY of the message write:
          UNSUBSCRIBE

Please use this address only for subscribing or unsubscribing.
--------------------------------------------------------------------

All Earth & Sky materials are copyrighted by Byrd & Block Communications Inc.
Permission to use, copy and distribute these materials without fee is hereby
granted, provided that:
    the above copyright notice appear in all copies and
    the materials are not redistributed for profit.

The Earth & Sky logo and "Earth & Sky" are registered trademarks of Byrd &
Block
Communications Inc.
###



% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Received: from mail.vbo.dec.com (mail.vbo.dec.com [16.36.208.34]) by vbormc.vbo.dec.com (8.7.3/8.7) with ESMTP id AAA01942 for <[email protected]>; Sat, 29 Mar 1997 00:12:59 +0200
% Received: from server21.digital.fr (server21.digital.fr [193.56.15.21]) by mail.vbo.dec.com (8.7.3/8.7) with ESMTP id XAA18954 for <[email protected]>; Fri, 28 Mar 1997 23:18:31 +0100 (MET)
% Received: from tpoint.net (challenger.tpoint.net [204.29.207.17]) by server21.digital.fr (8.7.5/8.7) with ESMTP id XAA26318 for <[email protected]>; Fri, 28 Mar 1997 23:23:18 +0100 (MET)
% Received:  by tpoint.net (8.8.2/25-eef) id UAA18880; Fri, 28 Mar 1997 20:29:35 GM
% Resent-Date: Fri, 28 Mar 1997 20:29:35 GMT
% X-Sender: [email protected]
% Message-Id: <v03007806af61d77c09c3@[206.160.162.42]>
% Mime-Version: 1.0
% Content-Type: text/plain; charset="us-ascii"
% Date: Fri, 28 Mar 1997 14:30:30 -0600
% To: [email protected]
% From: Lin Parafin <[email protected]>
% Subject: Earth & Sky: Week Beginning 3/31/97
% Resent-Message-ID: <"uK-HC1.0.dc4.Me2Fp"@challenger>
% Resent-From: [email protected]
% Reply-To: [email protected]
% X-Mailing-List: <[email protected]> archive/latest/75
% X-Loop: [email protected]
% Precedence: list
% Resent-Sender: [email protected]