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An astronomer had better be prepared to answer three questions: (Q1) Is there life elsewhere in the Universe? (A1: Yes, but we don't yet know where), (Q2) What was there before the Big Bang? (A2: I'll tell you as soon as you can tell me what's South of the South Pole), (Q3) What are black holes? This page is dedicated to Q3.
An astronomer, even if he/she works on planetary nebulae, should be prepared for The Three Questions when meeting anyone from the general public: (1) Is there life elsewhere in the Universe? (2) What was there before the Big Bang? (3) What are black holes? The answer to (1) is YES, but we don't know where yet; the answer to (2) is that such a question is intrinsically impossible, like the question `what is south of the South Pole?'; the answer to (3) is found on a vast quantity of Black Hole Web links. There's much more out there than I have listed, of course, but I think that these are extremely good ones. By the way, you can always tell the silly people from the genuinely curious, because the former always ask `What is the Black Hole?' in the singular. That is about as bizarre as asking `What is the star?' The only proper use of `the' in this way is with Winnie (who is, of course, THE Pooh).
Back in the Bad Old Days, before the Internet, you had to actually Write Things Up on paper, type them out, and hope somebody would publish it. So if you wanted to share your Views of the Weird Universe with someone, that was the way to go. And so I wrote an article in New Scientist (20/27 December 1979, pages 928-930) showing what Saturn would look like if the Sun were a black hole. If I had dressed it up a bit, added some obvious lines about cosmology, and published it in The Astrophysical Journal, my citation index would have skyrocketed. Let this be a lesson to you all! And no, the New Scientist paper is NOT on-line. But happily we live in the Internet age, and the following juicy sites are there for all to admire.
Werner Benger's home
page is the best I've seen so far. There's great stuff on black holes in general,
and a wonderful simulation of the warped paths of light and its
related visual effects, illustrated by means of our good old Planet Earth
as a black hole. Not only does Benger show some stunning graphics,
he also helps you along with extensive on-line publications regarding
the use of C and C++, and on the ray-tracing and related methods
he uses. Great stuff, colleague!
Another very nice one is Robert Nemiroff's site with simulations
of the bending
of light rays in strong gravitational fields. One of its virtues
is, that the physics documentation is very complete; it's almost
a mini-textbook on applied General Relativity.
A collection of visualizations of some effects
in special relativity, from the University of Tuebingen.
Andrew Hamilton's home
page contains some small but terrific movies
of relativistic effects. Furthermore, his plain-looking page
is very well branched and contains a wealth of very useful links
on astrophysics and relativity.
This plain-looking index from the U.S. National Center for Supercomputer
Applications hides an amazing array of simulations, sometimes
with video narration by the people who did the research. It
looks simple but it's juicy! Even the latest stuff on the
evolution
of black holes is included. There's a whole set of related
numerical relativity
displays from the NCSA. Browse and enjoy.
A remarkable exam project on the interactive presentation of null
geodesics is Bo Milvang-Jensen's paper on null
geodesics around a Kerr black hole. These Danes at the Niels
Bohr Institute are way ahead of most of us, it would appear.
The University of Pittsburgh
Relativity Group
has listed a whole page of simulations relating to black hole
evolution, including this wonderful fission
of a white hole.
Sam Hart shows images of his computations of particle
orbits near black holes, from which you may get some idea
about the structure of accretion disks. But this is not hydrodynamics,
so beware.
Steve VanDevender shows some stills of relativistic
spaceflight, and supplies the Unix XWindow code to go with
it.
Andrew Howard (whose name is modestly absent from his page) shows
a wonderful picture of flying
relativistically towards a cloudy sky, and gives you the source
code too.
Keywords: Astrophysics - Cosmology - Hydrodynamics - Visual Art