Conference 7.286::space

    	Forgive this question (it is NOT rhetorical), but are you saying
    that we - meaning the Universe - exist inside (or ARE) a black hole?!
    
    	If so, where and how did this black hole form, since our current
    theories say that black holes are the gravitational remains of a
    star three times larger than the Sun which crushed itself literally
    out of existence.
    	Based on this, how could an entire universe (or many, according
    to your theory), form from the final death act of a star?  
    	Or are you basing your theory on some NEW proposal for black
    hole formation which I am unaware of?
                                                 
    	Larry
    

    The important thing to remember is that the mass of the star isn't
    really the important factor, it is the gravity caused by the mass.
    Some scientists have theorized "small" black holes (of micro-meter
    sizes and relatively small mass compared to stellar mass) may have
    been formed due to the gravitational pressures which existed shortly
    after the "Big Bang".
    
    Normally one expects a large stellar mass is necessary to form a
    black hole, but not according to the above theory.  I'm not sure
    how that relates to us living inside a black hole (I feel like I
    work inside one sometimes, but that's beside the point), I just
    thought I'd share another of the oddball theories currently in
    vogue.
    

    Re .1
    
    We don't know if are inside a black hole or not, thats one of the
    major scientific questions still unanwered.
    
    Basicly, a black hole is (one or more stars) that collapsed on 
    themselves due to the great pull of their gravity. So great is
    the gravitational attraction that even light cannot escape it.
    (Thus the name  BLACK HOLE)
    
    We live in a black hole, if the universe has enough matter (i.e.
    gravitational attraction) to stop its current expansion of matter
    and light outwards. 
    
    

    1.  The S. radius is not the radius of the black hole.  It is the
    radius beyond which if something is squeezed it FORMS a black hole.
   
    2.  If something is squeezed beyond the S. radius, it does not
    immediately become a black hole.  It just becomes inevitable that it
    WILL become one.  Thus if the universe has enough mass, we could say we
    were living in a POTENTIAL black hole, but not actually IN a black
    hole, since said hole has not yet formed.
    
    But, as .3 said, that is one of the big questions of the day:  is
    there enough mass.  The question is more often posed as "Is there
    enough mass so that the universe is cyclical".  Note that there
    is another interesting question implicit here:  If before the big
    back there was a black hole, we must revise our thinking about black
    holes being forever.  Obviously they can explode into a universe!
    
    Burns
     
    

>   Basicly, a black hole is (one or more stars) that collapsed on
>   themselves due to the great pull of their gravity. So great is
>   the gravitational attraction that even light cannot escape it.
>   (Thus the name  BLACK HOLE)

I  wonder  how  many black holes are really a space craft moving at a
high percentage of "C"?  Mass increases as velocity increases, right?

>   We live in a black hole, if the universe has enough matter (i.e.
>   gravitational attraction) to stop its current expansion of matter
>   and light outwards.

In  the  above  case,  the  existance  of  the  black  hole  would be
determined by the point of the observer relative to the space  craft.
The pasengers would seem  to be surrounded by black holes,  not be in
one.

	-SES

    Black holes are not forever, they tend to evaporate. This is a result
    of combining Quantum Mechanics and General Relativity.
    
    S. Hawkings uses this result to eliminate the messy singularity
    that appears at time zero in plain General Relativity.
    
    "A black hole would emit particles and radiation like a hot body
    with a temperature which was higher the smaller the mass of the
    black hole. The radiation would carry away energy and so reduce
    the mass of the black hole. This in turn would increase the rate
    of emissions. Eventually, it seems that the black hole would disappear
    completely in a tremendous burst of emission."
    
    		"The Edge of Spacetime", S.W.Hawking _American_Scientist_
    			July-August 1984 pp355-359
    
                                                   
                  /
                 (  ___
                  ) ///
                 /
    

    	So could one say that the Big Bang was the result of a black
    hole - formed by the collapse of the previous universe before ours
    - exploding to create our Universe.
    
    	Perhaps all that "dark matter" cosmologists say exists in
    interstellar and intergalactic space will "add" enough to the mass
    of our Universe to pull it back upon itself into a new black hole,
    with the black hole then exploding again and creating another universe
    *ad infinitum*.
    
    	I wonder - perhaps our remote human descendants could escape
    our Universe by flying into a "local" black hole into another universe,
    thus escaping the collapse of ours - until of course THAT universe
    begins to collapse, or maybe they will find a universe which does
    NOT have enough matter to cave in on itself.
    	That universe will, however, dissipate eventually, forcing our
    descendants to forever be "universe hopping" - unless there is a
    stable universe out there somewhere.
    
    	I never put anything past humanity's abilities - and who can
    say what our posterity will be able to do millions and billions
    of years from now?
    
    	Larry
    

    The little I have heard about black holes leaves me with some
    questions about some of the preceding:
    
    1) Near-c spaceships.  Well, unless we observed the hole traveling
       at near-c, that would seem to be ruled out.
    
    2) Compression to < S. radius without (immediately) "becoming" a
       black hole.
    
       Once all the mass necessary for the creation of a B.H. has been
       compressed within the S. radius in question, how would one know?
    
       In other words, isn't the EXISTENCE of a real S. radius absolutely
       equivalent to the existence of the hole?
    
       Once the mass is inside, does its distribution in there matter?
       (For spherical distributions, Newtonian physics says it shouldn't
       - does G.T.R. modify this?  If not, then from the outside it
       should not matter further:  the "nothing can leave" - quantum
       exceptions noted - criterion will be satisfied immediately.)
    
    3) Along similar lines:  It would seem to me that if sufficient
       mass-energy is present in the Universe for it to BECOME a B.H.,
       then by definition it already IS a B.H.
    
       (An extension of the precept that distribution within the S.
        radius - if it in fact exists - is irrelevant.)
    
       The existence of a real S. radius does not imply that everything
       within is super-compressed in some manner - just that there is
       ENOUGH in a SMALL ENOUGH space to prevent photon emission.
    
       With a large enough space, mass distribution and gravity gradients
       within could be quite reasonable... like ours, for example.
    
    There may be problems with the mix of Newtonian and Einsteinian
    concepts in here, so if someone cared to elaborate it would be
    interesting.
    			- Bill
    

    An interesting story might involve the search for mass-energy loss
    in our Universe to prove/disprove whether it is indeed a B.H. within
    some larger continuum (assuming it's first found that it IS cyclic...).
    
    		- Bill
    

>   1) Near-c spaceships.  Well, unless we observed the hole traveling
>      at near-c, that would seem to be ruled out.

Interesting. Have you knowledge of ANY direct observations of black
holes (the astronomical type)?

	-SES

    A black hole forms from a stellar mass when the "outward" pressure
    caused by the internal nuclear processes is no longer sufficient
    to overcome the "inward" pressure of gravity.  Therefore, just
    having the mass isn't enough to create the black hole.
    
    As to whether we live in a black hole, I don't know.  Maybe that
    explains where socks disappear to when you launder them ...
    

    Oh, I forgot to mention (thought it was obvious, but ...) the
    mass must also be sufficient during collapse to overcome the
    inter-atomic forces in the atoms in the mass.  Otherwise someone
    might start thinking the Earth will turn into a black hole.
    

    re .11:
    
    > A black hole forms from a stellar mass when the "outward" pressure
    > caused by the internal nuclear processes is no longer sufficient
    > to overcome the "inward" pressure of gravity.  
    
    Yes, this is correct...
    
    > Therefore, just having the mass isn't enough to create the black hole.

    But, how does this follow? The mass is what creates "the inward pressure
    of gravity". Without the fusion process, a ball of that mass and
    diameter (of a sun 3 times the size of the sun) will collapse on
    itself and form a black hole. 
    
    The fusion process was the only thing preventing the inevitable.
                           
                                                   
                  /
                 (  ___
                  ) ///
                 /
    

    Mass alone isn't enough.  Your key words are "mass and diameter".
    Just having some specific mass won't do the trick if that mass is
    spread out through an area the size of a galaxy.  It must be
    concentrated in a small enough area (relatively speaking).  Mass
    and mass density are the determining factors.
    

    re .14:
    
    Actually, I think I am still right.
    
    If that mass is spread out over any amount of volume, if there are
    no other forces at work, that mass will eventually pull itself together
    into a star, burn for a while then collapse into a black hole.
    
    The diameter is what determines when it actually becomes a black
    hole, but it is only the mass that determines whether or not it'll
    eventually become a one.
                                                   
                  /
                 (  ___
                  ) ///
                 /
    

    I'll concede in normal conditions the collapse will happen if
    there is sufficient mass present at some time prior to the
    collapse.  "Time prior" may be a long time, though, as your
    example shows.
    
    However, as I also stated, theory has it that immediately after
    the "Big Bang" it is possible "mini" black holes were created.
    This would have been more due to applied forces than the mass
    of the hole.
    
    So in a pure sense mass isn't the only factor, but in the "real"
    world (strange term to apply to black holes, ain't it?) mass
    is enough.  Fair enough?
    

    re .16:
    
    fair enough.
    
    mini-black holes may have been formed but are probably long gone
    today due to the "Hawking evaporation effect".
    
    now that the quibbling is over...lets get to where the action is.
    
    Does the title of this note mean that there really is a deliberate
    mistake in the base note, and we are supposed to find it?
    
                                                   
                  /
                 (  ___
                  ) ///
                 /
    

    	It is now generally believed that most, if not all, of the
    mini-collapsars created at the time of the Big Bang have long since
    "evaporated", as their tiny size allowed them to disappear sooner.
         
    	Larry
    

    The only deliberate mistake in the base note that I am aware of
    is that I implied the S-radius was in some sense the size of
    the black hole itself. It is the radius which if the given mass
    is somehow compressed within it it will forma black hole, or
    alternatively it is the radius of a surface having an escape velocity
    of 'c'.
    
    Since the known Universe is believed to have started from a singularity
    or something close to one, it clearly started out within its S-radius.
    Also we may assume that the matter in the universe cannot exceed
    the speed of light. Hence it follows that the Universe has a maximum
    size determined by the S-radius. If we knew the total mass of the
    universe we could compute the S-radius, and hence know how large
    the universe may grow to be.
    
    If (and its only a suggestion) the universe is bounded by the s-radius
    then several of the current cosmological theories fail (because
    they require unlimited expansion.) 
    
    Also the current observational horizon is about 13000,000,000 light
    years, and even without dark matter that is not much less than the
    s-radius given the estimate of the matter in the universe I used
    (whatever the common figure was in 1971). This places the earth
    near the center of the physical universe, a conclusion which is
    generally considered un-acceptable.
    
    One theory of life within a black-hole suggests that (a) viewed
    from an interior point the gravitational field will make it appear
    that the contents are expanding (even if they aren't), and secondly
    matter falling through the s-radius boundary would create a background
    radiation.
    
    This would replace the big-bang by a return to a steady state
    cosmology: the observational horizon would correspond to the s-radius
    of a suitable volume of mass with ourselves at its center. The apparent
    expansion would be explained by gravitational theory, and the magic
    background radiation would also be explained by the theory.

    Incidentally since every point in space is the center of a sort of
    black hole in this theory it follows (since that is absurd) that
    this is only what we appear to observe as a result of seeing only
    the three physical dimensions in a poly-dimensional world...
    
    
    anyway, I like the way the debate is going ...
    
    /. Ian .\
    
    PS I once had the chance to discuss this with Richard Feynman at
    a conference, and there is a flaw in the argument, or so he said...

    I read somewhere that if you're just inside the event horizon of
    a black hole, you cannot get back out since the event horizon seems
    to be speeding away from you at the speed of light. Sounds very
    much like being inside an expanding universe to me.
    
    On the other hand we might have a situation that occurs often in
    physics, that the same formula can be used to describe different
    phenomena. The fact that the formula for the Swartzchild radius
    is used both for black holes and for our universe does not have
    to mean that we're inside a black hole or that black holes contain
    little expanding universes (rather than singularities).

    It's an intresting thought though. Too bad I don't know enough
    of the math to actually check the feasibility rather than just
    do some dreaming.

    						Bjorn    

    re "terracentrism":
    
    It looks like we're at the center of the universe because the universe
    is expanding uniformly. The analogy I like best is the flatlander
    living on the surface of a balloon. As the balloon continues to
    be inflated, the flatlander sees the horizon receding from him
    uniformly in all directions. Thus it appears that he is at the center
    of the expansion. Little does he know of the curvature through the
    third dimension.
    
    > If we knew the total mass of the universe we could compute the 
    > S-radius, and hence know how large the universe may grow to be.     
      
    The flaw here is that it is space itself that is expanding, the
    S-radius cannot be applied to the universe as a whole.
    
                                                   
                  /
                 (  ___
                  ) ///
                 /
    

    	In Carl Sagan's 1980 science book, COSMOS (adapted from the
    PBS-TV series), he made a comment that if you wanted to know what
    the inside of a collapsar was like, look around you.
    
    	Larry
    

    	The October, 1986 issue of ASTRONOMY magazine has an excellent
    article on collapsars, detailing the four main theoretical types.
                                                  
    	Larry
    

Associated Press Tue 07-OCT-1986 09:55                           Quasar Finds

        New Quasars That Throw Giant Cosmic Blobs Found 
 
  LOS ANGELES (AP) - Scientists watching the celestial objects
known as quasars have spotted giant blobs of cosmic material
shooting from seven of them, doubling the number of quasars known to
behave that way.
   The find, announced Monday, adds support to the theory that at
the heart of every quasar lies a black hole.
   The scientists used a network of radio telescopes in the United
States and Europe to study 67 quasars and radio galaxies. Quasars
are immensely bright objects near the distant fringes of the
universe. Radio galaxies are those which emit more energy as radio
waves than as light.
   During two recent periods of observation, they saw seven of the
quasars throw out jets of material trillions of miles long at nearly
the speed of light.
   Anthony Readhead, director of the California Institute of
Technology's Owens Valley Radio Observatory and the leader of the
team that made the discovery, said the scientists owe part of their
success to good timing.
   ``You have to be lucky and looking at it when it shoots out a new
                                                            More -->
Associated Press Tue 07-OCT-1986 09:55                  Quasar Finds (cont'd)

blob,'' he said.
   The discoveries bring to 14 the number of quasars known to emit
such jets of material. Readhead said he expects the number to rise
substantially as the experiment continues.
   As many as half of the quasars under observation could display
such characteristics, he speculated.
   Quasars are so far away that they should be almost invisible, yet
so bright that for many years astronomers thought they were nearby
stars.
   For years scientists have sought to understand what the source of
energy is for these relatively small objects that are five to 10
billion light years away from Earth.
   In 1969, for the first time, scientists observed that one quasar
was sending off material that was traveling so fast it had to be
moving at near the speed of light.
   That led some to speculate that the power that drives the quasar
must be a black hole. Such holes are believed to be the extremely
dense remnants of collapsed stars, with a gravitational pull so
strong that not even light can escape.
   For material to escape the black hole, it would have to be spun
                                                            More -->
Associated Press Tue 07-OCT-1986 09:55                  Quasar Finds (cont'd)

off from the outer edge of the quasar, and it would have to be
traveling at near the speed of light in order to escape the black
hole's gravitational field.
   That led to a flurry of excitement among astronomers who believed
that if the speculation were correct, it should be relatively easy
to find quasars that are sending off speedy jets of material, most
likely the debris from stars that were sucked into the gravitational
field and then disintegrated.
   In the following years, six more quasars were found to be
spitting out jet streams at speeds near that of light.
   Readhead said if such activity is common, that lends credence to
the theory that quasars are most likely powered by black holes.
That, in turn, could help scientists understand some of the most
fundamental driving forces in the universe.
   Many astronomers believe a black hole lies at the heart of every
galaxy.

      From the October 14, 1986 edition of Vogon News -

    Astronomers at the new La Palmaobservatory in the Canary Isles have
    carried out observations that can only be done once every 19 years.
    The position of what is believed to be a black hole at the centre of
    the galaxy was examined by using the moon as a shutter and observing
    the infra-red radiation from the dust cloud surrounding the object.

      Does anyone have any more information on this observation?

      Larry

Newsgroups: sci.space
Path: decwrl!decvax!ucbvax!ucbcad!ames!lll-lcc!seismo!mnetor!utzoo!utgpu!water!
Subject: Re: frozen stars
Posted: 3 Apr 87 18:43:06 GMT
Organization: U. of Waterloo, Ontario
 
    In article <870402092920.00001A93.AJFE.VE@UMass> [email protected] 
(Andy R. Steinberg) writes: 

>The is one thing that has been bugging about black holes for a long
>time. A black hole can only have 3 properties, mass, charge, and
>rotation. A static black hole has 1 event horizon, whereas a charged
>or rotating black hole has 2 event horizons. I don't understand how
>there can be 2 places where time stops(relative to an outside
>observer) and the escape velocity = c. I have heard somewhere that
>the outer event horizon is the ergosphere, but I don't know what
>an ergosphere is and can't find any reference to it.
 
At the risk of doing a gross oversimplification:
An event horizon is a boundary through which you cannot come back:
  i.e. any thing that goes in cannot go out even light (hence the
  black in the name Black hole).
 
The ergosphere is somewhat different. It is a region in which you
 cannot stand still with respect to (say) the distant stars.
 Let me elaborate a bit.
 
A non-rotating black hole (the first type that was discovered )
 has an event horizon : anything that goes in cannot come out.
 You can, however, stand still w.r.t. the distant stars, provided
 you are outside the event horizon.  It will take some expenditures
 in energy though, you have to counterbalance gravity. It is like
 stopping a satellite in the sky - i.e. prevent it from orbiting -
 and yet keep the rockets firing to prevent the satellite from falling
 down.
 
For a rotating black hole however, things are a bit more interesting.
 You still have an event horizon, as before, but this time it is
 distorted a bit as compared to the non-rotating BH. -- nothing magic
 here, it is similar as to why the Earth has a bulge, you can think
 of it as the effect of the centrifugal force. There is something new
 in this case however.  Remember the picture associated with a BH,
 i.e. that of a ball distorting a sheet of rubber -- hence the popular
 "gravity wells" that are sometimes printed on t-shirts. Now set
 the ball rotating around (say) the vertical axis. The rubber sheet
 is dragged along with the rotation, that is, it rotates with the ball.
 (Well up to a certain point, this is only an analogy). Something similar
 happens around a rotating black hole. The space-time is dragged along
 with the rotating black hole. Now, lets get back to that satellite,
 or rocket. Not only does it have to fight against the downward gravity
 to lay still w.r.t. the distant stars, but in addition it has to fight
 against the rotation of the space-time itself.  The problem is,
 can it succeed. The ergosphere is the region where even with infinite
 energy, the rocket fails to maintain a fix w.r.t. those stars.
 Note: it does not mean that you cannot get away from the ergosphere.
 Provided you are outside the event horizon, you can still get out,
 even if you are inside the ergosphere.  As an interesting side effect,
 it also means you can steal energy from a rotating black hole, by stealing
 some of the energy stored in that rotating space-time. (You don't have
 to go in the ergosphere to do it). -- A yeah, quantum gravity also
 predicts energy can be emitted from any BH through Hawking's radiation.
 
This is already long enough. I hope this clears up a few hazy notions.
 
I choose the stars.
  
-- 
Je'ro^me M. Lang	   ||    [email protected]        [email protected]
Dept of Applied Math       ||			  jmlang%[email protected]
U of Waterloo		   ||  	 jmlang%water%[email protected]

VNS MAIN NEWS:                            [Richard De Morgan, Chief Editor, VNS]
==============                            [Basingstoke, England                ]

    Science, Technology, Medicine, and Nature
    -----------------------------------------

    It has been confirmed that black holes lie at the center of Andromeda
    Galaxy (M31) and a smaller galaxy, M32.

  <><><><><><><>   VNS Edition : 1515    Thursday 25-Feb-1988   <><><><><><><>

From:	DECWRL::"[email protected]" 16-JAN-1992 
        16:53:45.55
To:	[email protected]
Subj:	NASA'S HST finds evidence of black hole in nucleus of galaxy M87 

Paula Cleggett-Haleim
Headquarters, Washington, D.C.         January 16, 1992
(Phone:  202/453-1547)                   9:30 A.M. EST

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone:  410/338-4514)

Dr. Tod Lauer
National Optical Astronomical Observatories, Tuscon,
Ariz.
(Phone:  602/325-9290)

Dr. Sandra Faber
University of California, Santa Cruz
(Phone:  408/459-2944)

RELEASE:  92-10

NASA'S HST FINDS EVIDENCE OF BLACK HOLE IN NUCLEUS OF GALAXY M87

     Astronomers reported today that they have found intriguing
evidence that a black hole, weighing over 2.6 billion times the mass of
the sun, exists at the center of the giant elliptical galaxy M87, based
upon images taken by NASA's Hubble Space Telescope (HST).  The images
show that stars become strongly concentrated towards the center of M87,
as if drawn into the center and held there by the gravitational field
of a massive black hole.

     These results were reported at the 179th meeting of the American
Astronomical Society in Atlanta by Dr. Tod R. Lauer, National Optical
Astronomy Observatories (NOAO), Tuscon, Ariz.; Dr. Sandra M. Faber,
University of California, Santa Cruz; Dr. C. Roger Lynds, NOAO, and
other members of the HST Wide Field/Planetary Camera (WF/PC) Imaging Team.

     M87 is at the center of a nearby cluster of galaxies in the
constellation of Virgo, 52 million light-years distant, and contains
more than 100 billion stars.  One of the brightest galaxies in the
local universe, M87 is visible in even small telescopes.

     Early in this century astronomers discovered a gigantic plume or
"jet" of plasma apparently ejected out of the M87 nucleus.  Later, the
jet and nucleus were found to emit strong radio and X-ray radiation.
However, the nature of the central "engine'' of this activity has long
remained a mystery.

     In 1978, the late Peter Young, California Institute of Technology,
leading a team of astronomers, announced that the central portions of
M87 visible from the ground appeared to be dominated by the gravity of
a massive black hole.  However, prior to the HST observations, more
recent ground-based observational and theoretical studies have failed
to confirm this picture.

     Lauer, Faber, Lynds and co-investigators on the WF/PC imaging team
used the new images obtained with the HST Planetary Camera to explore
the central structure of M87 much closer into its nucleus than is
possible from the ground.  The images show clearly that the stars in
M87 become densely concentrated towards the center, forming a bright
"cusp" of light at the heart of the galaxy.

     The central density of stars in M87 is at least 300 times greater
than expected for a normal giant elliptical galaxy and over 1,000 times
denser than the distribution of stars in the neighborhood of the sun.
In fact, the ultimate central density of stars in M87 may be even
higher, but its measurement is beyond the resolving power of even HST.

     "The central structure of M87 is a striking departure from what
the normal core of a giant elliptical galaxy would look like," said
Lauer.  "It strongly resembles a stellar cusp associated with a black
hole."  The cusp is visible as the steady increase in brightness of M87
toward its center.  Theoretical work suggests that such a cusp may form
as a central black hole grows and cause the center of the galaxy to
collapse outwards.

     Early in the life of M87 a "seed" black hole may have formed in
its nucleus from the merger of small black holes created by the
explosion of massive stars or perhaps from the gravitational collapse
of gas left over from the formation of M87.  Once formed, the seed
black hole would grow by feeding on gas and stars that passed by too
closely.  As the mass of the black hole increased, its gravity would
begin to dominate an increasingly larger volume of space.

     Stars, once freely orbiting in and out of the M87 core, would be
gradually pulled towards the center and then into orbits closely bound
to the black hole.  The whole core of the galaxy thus smoothly
collapses inward, and the density of stars near the very center becomes
extreme.  Some of these stars eventually may be consumed by the black
hole, fueling its growth further.  This leads to an interesting paradox
that one way to look for a black hole is to search for a strong
concentration of starlight at the center of a galaxy.

     The mass of the black hole is estimated at 2.6 billion times that
of the sun, based on comparing the density of stars in the cusp to
theoretical models computed by Peter Young a decade ago.

     Lauer emphasizes, however, that the HST images alone do not prove
conclusively the black hole's presence.  "It looks like a 'duck' but we
haven't heard it 'quack' yet," he observed.  Follow-on HST
spectroscopic observations are needed to measure the velocity of stars
orbiting within the nucleus.  High velocities would be evidence of a black 
hole and would provide astronomers with direct measurement of its mass.

     The search for super massive black holes in the cores of galaxies
is one of the primary missions of NASA's Hubble Space Telescope.  By
investigating both active and quiescent galaxies, astronomers will have
a better idea of the conditions and events which lead to the formation
and growth of super-massive black holes.

                     - end -

A videotape showing three sequences of M87 is available by calling
NASA Headquarters Audio-Visual Branch on 202/453-8594. 

Also, a photograph to accompany this release is available by calling
NASA Headquarters Audio-Visual Branch on 202/453-8375: 

     B&W:    92-H-23
     Color:   92-HC-21

From:	US4RMC::"[email protected]" "It's not easy having a good time.....
        even smiling makes my face ache." 25-MAY-1994 13:13:07.50
To:	distribution:;@us4rmc.pko.dec.com 
CC:	
Subj:	STScI-PR94-23

                                   	EMBARGOED UNTIL:  1:00 P.M.  EDT
CONTACT:  Ray Villard, STScI                     Wednesday, May 25, 1994
          (410) 338-4514
                                   	PRESS RELEASE NO.: STScI-PR94-23
          
          Dr. Holland Ford, STScI/JHU
          (410) 338-4803
          (410) 516-8653

HUBBLE CONFIRMS EXISTENCE OF MASSIVE BLACK HOLE AT HEART OF ACTIVE GALAXY

Astronomers using NASA's Hubble Space Telescope have found seemingly
conclusive evidence for a massive black hole in the center of the
giant elliptical galaxy M87, located 50 million light years away in
the constellation Virgo.  Earlier observations suggested the black
hole was present, but were not decisive.

This observation provides very strong support for the existence of
gravitationally collapsed objects, which were predicted 80 years ago
by Albert Einstein's general theory of relativity.  

"If it isn't a black hole, then I don't know what it is," says Dr.
Holland Ford of the Space Telescope Science Institute and The Johns
Hopkins University in Baltimore, Maryland.

"A massive black hole is actually the conservative explanation for
what we see in M87.  If it's not a black hole, it must be something
even harder to understand with our present theories of astrophysics,"
adds fellow investigator Dr. Richard Harms of the Applied Research
Corp. in Landover, Maryland.

The discovery is based on velocity measurements of a whirlpool of hot
gas that is orbiting around the black hole in the form of a disk.  The
presence of the disk, discovered in recent Hubble images,  allows for
an unprecedented, precise measurement of the mass of the object at the
hub of the disk.

A black hole is an object that is so massive yet compact nothing can
escape its gravitational pull, not even light.  The object at the
center of M87 fits that description.  It weights as much as three
billion suns, but is concentrated into a space no larger than our
solar system. 

Now that astronomers have seen the signature of the tremendous
gravitational field at the center of M87, it is clear that the region
contains only a fraction of the number of stars that would be
necessary to create such a powerful attraction.  There must be
something else there that cannot be seen.

Ford and Harms were astounded by the M87 images taken with the
telescope's Wide Field Planetary Camera-2 (in PC mode) on Feb. 27. 
They hadn't anticipated seeing such clear evidence of a gaseous disk
in the center of M87.

"It's just totally unexpected to see the spiral-like structure in the
center of an elliptical galaxy," Ford says.

Ford and Harms used HST's Faint Object Spectrograph to measure the
speeds of orbiting gas on either side of the disk from regions located
about 60 light-years from the black hole at the center.

They calculated that the disk of hot (about 10,000 Kelvin), ionized
gas is rotating at tremendous speeds around a central object that is
extremely massive but extraordinarily compact -- a black hole.

"Once you get that measurement, all you need is straightforward
Newtonian physics to calculate the mass of the central object that's
making the disk spin," says Harms. 

The measurement was made by studying how the light from the disk is
blueshifted and redshifted -- as one side of the disk spins toward us
and the other side spins away from us.  The gas on one side of the
disk is speeding away from Earth, at a speed of about 1.2 million
miles per hour (550 kilometers per second).  The gas on the other side
of the disk is whipping around at the same speed, but in the opposite
direction, as it approaches viewers on Earth.

"Now, it all knits together," Ford said.  "We see a disk-like
structure that appears to have spiral structure, and it's rotating. 
One side is approaching, and the other is receding." 

The cloud of gas is composed mostly of hydrogen.  The hydrogen atoms
have been ionized, or stripped of their single electron, possibly by
radiation originating near the black hole.

Over the next few months, they will attempt to peer even closer to the
center, where the disk should be spinning at even higher speeds,
improving the measurement of the black hole's mass. 

M87: A NEARBY ACTIVE GALAXY

Since observations as early as 1917, astronomers have suspected that
unusual activity was taking place in the center of M87.  They
discovered a long finger of energy emanating from the nucleus. 
Investigations using radio telescopes in the 1950s detected large
emissions of energy from the galaxy.  This made it clear that the
bright optical jet and radio source were the result of energy released
by something in the center of the galaxy. 

In high resolution images, the jet appears as a string of knots (some
as small as ten light-years across) within a widening cone extending
out from M87's core.  A massive black hole had been the suspected
"engine" for generating the enormous energies that power the jet.  The
gravitational energy is released by gas falling into the black hole,
producing a beam or jet of electrons spiraling outward at nearly the
speed of light. 

HUNTING FOR BLACK HOLES

Hubble's observation confirms more than two centuries of theory and
conjecture about the reality of black holes.  The term black hole was
coined in 1967 by American physicist John Wheeler.  However, French
scientist Simone Pierre LaPlace first speculated that "dark stars"
might exist, which would have such intense gravitation that light
itself could not escape.  This conjecture was put into a theoretical
framework with Einstein's general theory of relativity, published in
1915, which postulated that very massive objects actually warp space
and time.  The theory was supported in 1916 when German physicist Karl
Schwarzschild described the mathematical basis behind black holes.

For decades, however, black holes were regarded not as real
astronomical objects, but merely as mathematical curiosities.  With
the discovery of active galaxies and quasars, black holes have become
the favored "engine" for explaining a wide array of powerful and
energetic events seen in the universe.

Earlier Hubble Space Telescope observations found strong
circumstantial evidence for the presence of a massive black hole in
the core of M87, as well and other galaxies -- both active and
quiescent.  These observations show a rapid increase in starlight
toward the center of a galaxy.  This suggests that stars are
concentrated around the center due to the gravitational pull of a
massive black hole.  However, the black hole's mass could not be
determined until Hubble's spectroscopic capabilities were used to
measure the actual motion of gas around the black hole.  Such high
spatial resolution spectroscopic observations were not possible prior
to the installation of the COSTAR by the astronauts during the
December 1993 First Servicing Mission.

The research team included Holland Ford at the Johns Hopkins
University and STScI; Richard Harms at Applied Research Corp. in
Landover, Md.; and astronomers Zlatan Tsvetanov, Arthur Davidsen, and
Gerard Kriss at Johns Hopkins; Ralph Bohlin and George Hartig at Space
Telescope Science Institute; Linda Dressel and Ajay K. Kochhar at
Applied Research Corp. in Landover, Md.; and Bruce Margon from the
University of Washington in Seattle.

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

The Space Telescope Science Institute is operated by the Association
of Universities for Research in Astronomy, Inc. (AURA) for NASA, under
contract with the Goddard Space Flight Center, Greenbelt, MD.  The
Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency (ESA). 

PHOTO CAPTION  STScI-PR94-23a           FOR RELEASE: Wednesday, May 25, 1994  

               HUBBLE OBSERVES SPIRAL GAS DISK IN ACTIVE GALAXY

A NASA Hubble Space Telescope image of a spiral-shaped disk of hot gas
in the core of active galaxy M87.  HST measurements show the disk is
rotating so rapidly it contains a massive black hole at its hub.

A black hole is an object that is so massive yet compact nothing can
escape its gravitational pull, not even light.  The object at the
center of M87 fits that description.  It weights as much as three
billion suns, but is concentrated into a space no larger than our
solar system. 

Now that astronomers have seen the signature of the tremendous
gravitational field at the center of M87, it is clear that the region
contains only a fraction of the number of stars that would be
necessary to create such a powerful attraction.

The giant elliptical galaxy M87 is located 50 million light-years away
in the constellation Virgo.  Earlier observations suggested the black
hole was present, but were not decisive.  A brilliant jet of high-
speed electrons that emits from the nucleus (diagonal line across
image) is believed to be produced by the black hole "engine."

The image was taken with HST's Wide Field Planetary Camera 2 

Credit:   Holland Ford, Space Telescope Science Institute/Johns
          Hopkins University; Richard Harms, Applied Research Corp.;
          Zlatan Tsvetanov,  Arthur Davidsen, and Gerard Kriss at
          Johns Hopkins; Ralph Bohlin and George Hartig at Space
          Telescope Science Institute; Linda Dressel and Ajay K.
          Kochhar at Applied Research Corp. in Landover, Md.; and
          Bruce Margon from the University of Washington in Seattle.
     
          NASA

PHOTO CAPTION  STScI-PR94-23b           FOR RELEASE: Wednesday, May 25, 1994  

             HUBBLE MEASURES VELOCITY OF GAS ORBITING BLACK HOLE

A schematic diagram of velocity measurements of a rotating disk of hot
gas in the core of active galaxy M87. 

The measurement was made by studying how the light from the disk is
redshifted and blueshifted -- as part of the swirling disk spins in
earth's direction and the other side spins away from earth.  The gas
on one side of the disk is speeding away from Earth, at a speed of
about 1.2 million miles per hour (550 kilometers per second).  The gas
on the other side of the disk is orbiting around at the same speed,
but in the opposite direction, as it approaches viewers on Earth.

This high velocity is the signature of the tremendous gravitational
field at the center of M87.  This is clear evidence that the region
harbors a massive black hole, since it contains only a fraction of the
number of stars that would be necessary to create such a powerful
attraction.

A black hole is an object that is so massive yet compact nothing can
escape its gravitational pull, not even light.  The object at the
center of M87 fits that description.  It weights as much as three
billion suns, but is concentrated into a space no larger than our
solar system. 

The observations were made with HST's Faint Object Spectrograph. 

Credit:   Holland Ford, Space Telescope Science Institute/Johns
          Hopkins University; Richard Harms, Applied Research Corp.;
          Zlatan Tsvetanov,  Arthur Davidsen, and Gerard Kriss at
          Johns Hopkins; Ralph Bohlin and George Hartig at Space
          Telescope Science Institute; Linda Dressel and  Ajay K.
          Kochhar at Applied Research Corp. in Landover, Md.; and
          Bruce Margon from the University of Washington in Seattle.

          NASA

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date: Wed, 25 May 1994 13:01:08 -0500 (EST)
% Subject: STScI-PR94-23
% To: distribution:;@us4rmc.pko.dec.com 

From:	US4RMC::"ASTRO%[email protected]" "Astronomy Discussion 
        List" 25-JUN-1994 08:40:30.25
To:	Multiple recipients of list ASTRO <ASTRO%[email protected]>
CC:	
Subj:	Possibly avoiding Black Hole in M87: Magnetic dragging

From Skyweek 24/1994:

According to W. Kundt, Bonn (Germany), the Hubble discoveries in M87 do not
necessarily imply a huge mass in the core of the galaxy. The high velocity
around the galaxy's center measured for the gas could be caused by dragging
of the gaseous matter by magnetic fields, without too exotic assumptions.

Only the measurement of the velocities of the stars could make clear if
there really is such an enormous mass (2..3E9 suns) as was reported, but
unfortunately that was not possible to now.

  Hartmut Frommert             | Russia HAS a space station !
  <[email protected]> | Mars Observer 2 would have survived.
----------- Get astronomical and space gifs via anon ftp from: -------------
explorer.arc.nasa.gov: /pub/SPACE/GIF; ftp.univ-rennes1.fr; ftp.cnam.fr    |
seds.lpl.arizona.edu; images.jsc.nasa.gov; jplinfo.jpl.nasa.gov; | Updates |
Hubble: stsci.edu: /stsci/epa/gif  Clementine: clementine.s1.gov | welcome |

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date:         Sat, 25 Jun 1994 14:29:34 +0100
% Reply-To: Astronomy Discussion List <ASTRO%[email protected]>
% Sender: Astronomy Discussion List <ASTRO%[email protected]>
% From: Hartmut Frommert <[email protected]>
% Subject:      Possibly avoiding Black Hole in M87: Magnetic dragging
% X-To:         ASTRO%[email protected]
% To: Multiple recipients of list ASTRO <ASTRO%[email protected]>