Conference 7.286::space

From: [email protected] (Ethan Tecumseh Vishniac)
Newsgroups: sci.space,sci.astro
Subject: Re: Dyson Sphere Discovered?
Date: 12 Nov 87 14:55:09 GMT
Organization: UTexas Computation Center, Austin, Texas
  
    The evidence for a brown dwarf is an infrared excess.  There is
some argument, which I have not seen, for discarding the possibility
of a cloud of dust causing the excess.  A Dyson sphere is one logical
possibility for the excess but, in the absence of corroborating
evidence for a technologically advanced civilization near that star,
it would be ludicrous to cite this as evidence for aliens. 
 
 "I'm not afraid of dying,   Ethan Vishniac, Dept of Astronomy
 I just don't want to be     {charm,ut-sally,ut-ngp,noao}!utastro!ethan
 there when it happens."     (arpanet) [email protected]
    - Woody Allen            (bitnet) ethan%[email protected]

From: [email protected] (Ed Nather)
Newsgroups: sci.space,sci.astro
Subject: Re: Dyson Sphere Discovered?
Date: 12 Nov 87 15:00:04 GMT
Organization: U. Texas CS Dept., Austin, Texas
 
    In article <[email protected]>, [email protected]
(Jim Kempf) writes: 

> Does anyone know any details about the brown dwarf Ben Zuckerman discovered
> around Giclas 29-38?  Zuckerman was quoted in the article I read saying that
> he believed it might be a Dyson sphere-like construction for converting part
> of the star's energy with excess heat as the byproduct. Apparently, Zuckerman
> has been a SETI skeptic, so the evidence must have been convincing.
 
    Zuckerman and Becklin discovered an unexpected excess of infrared
(IR) radiation in the direction of the variable white dwarf star
G29-38, an object much studied by our group at Texas because of its
intrinsic variability - it is the brightest of the known oscillating
white dwarf stars.  They interpret this excess as coming from a solid
object in orbit, but there is no evidence that it is a solid object,
and none that it is in orbit.  It could be a cloud of dust in that
direction. 
 
    We explored our records of the variability and found no evidence
for any periodic effect that might be attributed to orbital motion. 
It is quite a leap of faith to make that observation into a Dyson sphere. 

Ed Nather
Astronomy Dept, U of Texas @ Austin
{allegra,ihnp4}!{noao,ut-sally}!utastro!nather
[email protected]

From: [email protected] (Bill Wyatt)
Newsgroups: sci.space
Subject: Brown Dwarf and media idiocy
Date: 12 Nov 87 18:16:27 GMT
Organization: Harvard-Smithsonian Ctr. for Astrophysics
 
    Did anyone else see the Cable News Network (CNN) story on Ben
Zuckerman's Brown Dwarf discovery?  Regardless of whether the object
is real, is a brown dwarf star, or whatever, I am incensed at the
sloppy and downright ignorant way CNN reported the story.  The
following is from memory, so the details might be off, but: 
 
    Before a commercial, they tease you with `Tenth planet discovered!
More after this...' 
 
    Then, they say a brown dwarf has been discovered 50 million
light-years away (yes, that is *million*), and cut to footage of the
telescopes on Mauna Kea, used in the observations.  They then cut to a
graphic showing a big darkish object in orbit (you can see the circle,
so you know it is in orbit) around a white dwarf.  Lots of talk and
voiceover by Zuckerman about the object.  Finally, in the story
wrap-up, the CNN anchorperson makes another reference to `the tenth
planet'. 
 
    During the story, *no* reference was made to what Zuckerman et.al.
*actually* did or *actually* observerd (i.e. observed an infrared
excess), or even why a brown dwarf is interesting/controversial. 
 
    So how could such an *ignorant* story get out?!  Something in
another system is obviously not a `tenth planet', and where did that
50Mly number come from, putting it out beyond the Virgo Supercluster
somewhere!  And the story itself had so little information content
that even I, as involved with astronomy as I am, could not read
between the lines to figure out what was happening. 
 
    It is a sad commentary on the U.S. educational system when none of
the people making up that broadcast knew enough science to avoid the
idiocies in the story as broadcast. 
 
Bill    UUCP:  {seismo|ihnp4}!harvard!cfa!wyatt
Wyatt   ARPA:  [email protected]
         (or)  wyatt%[email protected]
      BITNET:  wyatt@cfa2
        SPAN:  17410::wyatt   (this will change, sometime)

From: [email protected] (Rodney Doyle Van Meter III)
Newsgroups: sci.space,sci.astro
Subject: Re: Dyson Sphere Discovered?
Date: 13 Nov 87 21:10:19 GMT
Organization: Information Sciences Institute, Univ. of So. California
 
    In article <[email protected]> [email protected] (Jim
Kempf) writes: 

>Does anyone know any details about the brown dwarf Ben Zuckerman discovered
>around Giclas 29-38?  Zuckerman was quoted in the article I read saying that
>he believed it might be a Dyson sphere-like construction for converting part
>of the star's energy with excess heat as the byproduct. Apparently, Zuckerman
>has been a SETI skeptic, so the evidence must have been convincing.
>
>		Jim Kempf	[email protected]
 
    That does not sound at all right to me.  A Dyson Sphere has to be
completely encircling the star, not letting out much radiation at all.
Perhaps the construct is something like SF author Larry Niven's
Ringworld?  I saw an article that said it was found due to there being
more infrared coming from the vicinty than the star alone could
account for.  It has not yet been confirmed by a wobble in the star's
orbit or anything, but it is speculated to be a gas giant planet,
something like Jupiter, but no estimations of mass yet.  The article
was also a little skeptical, as researchers have thought they have
found extrasolar planets before, but none of them have panned out.  I
am with the "wait and see crowd" on this one. 
 
		--Rod
 

From: [email protected] (Doug Mink)
Newsgroups: sci.space,sci.astro
Subject: Re: Dyson Sphere Discovered?
Date: 16 Nov 87 18:02:16 GMT
Organization: Harvard-Smithsonian Ctr. for Astrophysics
 
    in article <[email protected]>, [email protected]
(Jim Kempf) says: 

> Xref: cfa sci.space:3427 sci.astro:1473
> 
> Does anyone know any details about the brown dwarf Ben Zuckerman discovered
> around Giclas 29-38?  Zuckerman was quoted in the article I read saying that
> he believed it might be a Dyson sphere-like construction for converting part
> of the star's energy with excess heat as the byproduct. Apparently, Zuckerman
> has been a SETI skeptic, so the evidence must have been convincing.
 
    I heard Zuckerman's presentation of his results in Pasadena last
week at the annual meeting of the Division for Planetary Science of
the American Astronomical Society.  There was some interesting
last-minute politicking over whether he could release his results
before they came out in NATURE magazine later in the week, and the
paper was inserted at the last minute. 
 
    He said that the most likely cause of the infrared excess is a
Jupiter-sized (more or less) object which is emitting energy from
gravitational collapse rather than hydrogen burning.  A dust cloud was
ruled out due to the fact that a cloud close enough to the star to
keep it a point source would not be stable.  The Dyson sphere -
actually he referred to several large artificial solar collectors in
orbit around the star - was another hypothesis, offered because he
could not rule it out.  Zuckerman has been not only a SETI skeptic, but
a planet search skeptic.  The rest of the planetary science community
accepts his spectrum, but, having been burned several times in the
past, reserves judgment on what is causing the infrared excess. 
Needless to say, this star will be a subject of intense study. 
 
Doug Mink
Harvard-Smithsonian Center for Astrophysics
Cambridge, Massachusetts
[email protected]
{seismo|ihnp4}!harvard!cfa!mink

From: [email protected]
Newsgroups: sci.space
Subject: Planet-like Object found beyond our Solar System
Date: 16 Nov 87 17:51:00 GMT
 
    Here is a little something I copied from THE WASHINGTON POST -
(11/16/87) 
 
    PLANET-LIKE OBJECT OBSERVED BEYOND THE SOLAR SYSTEM
 
    The first good evidence of a planet-like object beyond the Solar
System has emerged from detailed observations near a star about fifty 
light years from Earth.  An object seen in the region may be the first
known brown dwarf, a hypothetical body intermediate in size between a
planet and a star.  If confirmed, the discover would lend support to
the idea of life in other solar systems.  As long as our Solar System
contained the only known planets, it was hard to estimate how common
such objects might be.  A second example so close by - 50 light years
is nearby on the galactic scale - suggests planetary systems are
fairly common. 

    The discovery may also help solve the so-called missing mass
problem.  The observed mass of the Universe accounts for only about
ten percent of the gravitational force that appears to be operating in
space.  If it turns out there are many brown dwarfs, they could
account for a share of the missing mass.  The discovery was reported
in last week's NATURE magazine by Benjamin Zuckerman of UCLA and Eric
Becklin of the University of Hawaii.  Other planet-like objects have
been reported in the past, but all have faded from believability
because repeated attempts to see them failed.  Better established are
signs of disks of material around stars that appeared to be early
stages of forming planetary systems. 

    The difference between a star and a planet is chiefly one of mass.
When interstellar gas and dust accrete into a ball, pressure builds up
at the center.  If enough mass builds up, the pressure and the heat
can become great enough to start a thermonuclear chain reaction, the
same process that makes a hydrogen bomb blow up.  This is what makes
stars shine.  If the mass is too small to do this, the result can be
anything from a cold lump of rock to a planet such as Jupiter that,
unlike Earth, gives off more heat from its internal pressure than it
receives from the Sun.  If Jupiter, the largest planet in our system,
were about 75 times more massive, its internal pressures would be
enough to ignite nuclear reactions and turn it into a star. 

    A brown dwarf would be a body many times larger than Jupiter, but
not big enough to turn into a star.  It would send out heat resembling
the infrared radiation that Zuckerman and Becklin detected as coming
from a point in the sky near the white dwarf star Giclas 29-38.  The
mystery object appears to have a surface temperature of around 1,700
degrees Fahrenheit, much too cool to be a star, but about ten times
hotter than Jupiter. 

    Well, not to defend CNN.....but if the object does happen to be
    a planet, it would qualify as the tenth known planet.  It just wouldn't
    be a part of our solar system.
    
    				-Jeff

    I hate to hit CNN too hard.  Up till January 28, 1986, they were
    about the only place to watch a shuttle launch with little, if any,
    commentator B.S.
    
    Burns