Open Questions: Black Holes

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See also: Quantum gravity -- Galaxy formation, structure, and evolution -- Quasars and active galactic nuclei -- M-theory

Region around black hole of Centaurus A

See HubbleSite page for information.


Existence of black holes

Nature of central singularity

Relation to wormholes

Relation to quantum gravity

Intermediate mass black holes

Black holes & galaxy formation

Black holes & information

Black holes & string theory

End of black hole evaporation

Naked singularities

Artificial black holes

Black hole information paradox

Recommended references: Web sites

Recommended references: Magazine/journal articles

Recommended references: Books


Recommended references: Web sites

Site indexes

Open Directory Project: Black Holes
Categorized and annotated links. A version of this list is at Google, with entries sorted in "page rank" order.
The Net Advance of Physics: Black Holes
An index of tutorial and research articles located at the physics preprint archive.
Yahoo News Full Coverage: Black Holes
Links to recent news stories from various sources. Also includes links to sites dealing with black holes.
Galaxy: Black Holes
Categorized site directory. Entries usually include descriptive annotations. More here.
Yahoo Directory: Black Holes
Annotated list of links.

Sites with general resources

Virtual Trips to Black Holes and Neutron Stars
By Robert Nemiroff.
Movies from Numerical Relativity Simulations
Downloadable animations and visualizations mostly related to black holes, but also neutron stars and Brill waves. Created by the National Center for Supercomputer Applications (NCSA).
Falling Into a Black Hole
Animations and a large quantity of technical information. By Andrew Hamilton.
Binary Black Hole Home Page
This is the home page of the "Binary Black Hole Grand Challenge Alliance", a group working to develop computer models of binary black hole coalescence. This process is considered likely to generate strong gravitational waves. More here.
HubbleSite News and Views: Black Holes
Press releases and images related to black holes, from HubbleSite.
TMR Network: Accretion onto Black Holes, Compact Stars, and Protostars
Web site for a research collaboration investigating accretion of matter onto black holes.

Surveys, overviews, tutorials

Black Holes FAQ
Very good answers to the basic questions about black holes, by Ted Bunn.
Sci.physics FAQ on Black Holes
Another good FAQ list, by Matt McIrvin. May also be found here.
Jillian's Guide to Black Holes
A light-hearted introduction to the subject, with useful references and external links. By Jillian Bornak.
Black hole
Article from Wikipedia. See also Supermassive black hole
Q & A: Black Holes
Fairly extensive frequently-asked questions and answers, at the Chandra X-ray Observatory site.
Black Holes
Part of the Cambridge Relativity site. Includes an introduction to black holes, discussion of observational evidence, and video animations.
Black Holes and Quantum Gravity
Brief article from the Cambridge Relativity pages. Touches on quantum gravity.
Black Holes
Part of NASA's Imagine the Universe site. Contains basic information about black holes, computer animations, and links to related topics. There is also a page on the growth of massive black holes, and a more advanced level page on the topic.
Frequently Asked Questions About Black Holes
Very good set of questions and answers, by John Simonetti.
Black Holes and X-ray Astronomy
Contains some good tutorial essays on black holes, the galactic center, and quasars. Written by Simon Vaughan.
Ask a High-Energy Astronomer: Black Holes
Common questions, with answers, provided by NASA's Ask a High-Energy Astronomer service.
Home Page of Barrett O'Neill
Contains short articles based on his book, The Geometry of Kerr Black Holes.
Coming soon: First pictures of a black hole
May 2009 New Scientist article. "You can't see a black hole directly, but you can see its shadow - and now vast telescopes are ready to get their first glimpse of the cosmic monster at the heart of our galaxy."
Black holes, but not as we know them
January 22, 2005 article from New Scientist. Describes new theoretical ideas about black holes and connections with string theory.
Twisted Physics: How Black Holes Spout Off
August 2004 article from Discusses differing theories of jets associated with black holes.
Explore Black Holes
Collection of news stories, broadcast transcripts, and articles about black holes at ABC News (Australia).
Black Holes: Dark and Deadly
February 2007 article from Transcript of an interview with Neil Tyson about black holes and his new book Death by Black Hole and other Cosmic Quandaries.
Getting a Grip on Black Holes
February 2007 article from Discusses the opinions of black hole experts on what they think are the most important open questions about black holes.
The True Shape of Black Holes
September 2003 article from Discusses the spin and geometry of black holes.
Voyage into the Vortex: Survival Tips for Black Hole Travelers
April 2003 article from Discusses different possibilities for the internal structure of black holes.
The New History of Black Holes: 'Co-evolution' Dramatically Alters Dark Reputation
January 2003 article from Discusses a relatively new theory of how black holes and galaxies might develop together.
The Music of Black Holes
April 2002 article from Discusses the music-like variability of x-ray emissions from black holes.
Monster Black Holes: How Galactic Collisions Fed Them
June 2001 article from Discusses how supermassive black holes formed when galaxies collided and merged in the early universe.
Opportunistic Black Holes Are No Suckers
June 2001 article from It explains how the the gravitational field of a black hole is no stronger than that of a star of equal mass.
New Spin on Black Holes: Like Stars, They Rotate
May 2001 article from Discusses observations which indicate the existence of spinning black holes.
Black Holes
Overview from Stephen Hawking's Universe.
Black Holes and Neutron Stars
Several pages on the subject, by Chris Miller. Includes questions and answers, a bibliography, and external links.
Black Holes
Good tutorial from Mike Guidry's Violence in the Cosmos.
Black Holes
A set of pages from the Official String Theory Web site about how relatively recent developments in string theory help explain the entropy of black holes and the "black hole information problem".
The Black Hole Information Loss Problem
Article by Warren G. Anderson.
Black Holes and Beyond
Excellent multimedia site created by the National Center for Supercomputer Applications (NCSA). Provides extensive tutorial on the physics of black holes and how they are studied by means of computer modeling. Contains some computer animations of black holes and gravitational waves, called Movies from the Edge of Spacetime.
The Case for Discrete Energy Levels of a Black Hole
Slide presentation given by Jacob Bekenstein at the 2001: A Spacetime Odyssey conference.
How Do We See Black Holes?
Brief tutorial introduction by John Blondin.
The Naked Singularity
Series of brief overview articles on black holes, Hawking radiation, the information paradox, and more.
If light cannot escape the gravitational pull of black holes, how is it that scientists have detected plumes of radiation coming from them?
Scientific American page with answers and external links from several experts.
The Search for Black Holes
Survey paper by Steven Degennaro. Focuses on how Cygnus X-1 was identified as a black hole.
Black Holes
Part of the Chandra X-Ray Observatory Center. Provides overviews of stellar, mid-size, and supermassive black holes.
Almost certain escape from a black hole
September 2006 article from Physics World, by Seth Lloyd. "Recent theoretical results have overturned the long-held notion that information cannot escape from a black hole."
Supermassive black holes
June 2002 article from Physics World, by Laura Ferrarese and David Merritt, subtitled "Astronomers have confirmed that black holes weighing billions of solar masses lie at the heart of every galaxy and believe that some galaxies might contain pairs of black holes."
Black holes and beyond
February 2002 editorial from Physics World which deals with some of the peculiarities of the theory of black holes.
DIY black holes could supply the missing link
January 2001 news article from Physics World about possible ways to make laboratory models of black holes.
Frozen Stars
July 2003 Scientific American article. "Black holes may not be bottomless pits after all."
Black Holes Sing
October 2007 Scientific American article. "Although sound cannot be heard in space, it can sometimes be seen."
Black Hole
Brief January 2003 overview of black holes by Karl S. Kruszelnicki.
Black hole recipe: Slow light, swirl atoms
February 2000 news article in Science News about the possibility of making laboratory models of black holes by optical techniques.
Black Holes: The Ultimate Abyss
1997 tutorial article on black holes, based on an Australian Broadcasting Company TV program.
Lone black holes adrift in the galaxy
January 2000 news article about stellar mass black holes that are not part of a binary system.
Black Holes
Brief article on black holes, based on an Australian Broadcasting Company radio program.
When black holes collide
September 1999 news article about computer simulation of black hole collisions.

Press releases, news stories

Deepest X-Rays Ever Reveal Universe Teeming With Black Holes
March 13, 2001 press release on a discovery made by the Chandra X-Ray Observatory.
Chandra Spies on Black Holes in a Nearby Galaxy
May 15, 2001 news article from Scientific American.
Scientists Verify That Some Black Holes Spin
May 2, 2001 news article from Scientific American.
Black Hole Hiding Nearby
March 12, 2001 news article from Scientific American regarding confirmation of the existence of a supermassive black hole at the center of the Centaurus A galaxy.
Looking for Black Holes in the Dark
January 12, 2001 news article from Scientific American.
Black Holes: More, Younger and Meaner
December 14, 2000 news article from Scientific American.
Black Holes Linked to Star Births
November 8, 2000 news article from Scientific American.
A New Black Hole
September 13, 2000 news article from Scientific American.
New Evidence for Black Holes
January 12, 2001 NASA press release. "By seeing almost nothing, astronomers say they've discovered something extraordinary: the event horizons of black holes in space."
'Death Spiral' Around a Black Hole Yields Tantalizing Evidence of an Event Horizon
January 11, 2001 press release and related information from the Space Telescope Science Institute. The object in question is Cygnus XR-1.
Astronomers find middleweight black hole
September 14, 2000 news article from Physics Web. "An international team of astronomers has identified a new kind of black hole. The Chandra X-ray telescope detected the medium-sized black hole, which is about the size of the Moon but has a mass at least 500 times that of the Sun."
Astronomers Find a New Size of Black Hole
September 13, 2000 New York Times article on the discovery of midsize black holes.
A Cosmic Searchlight
July 6, 2000 press release and related information from the Space Telescope Science Institute. The image is a relativistic particle jet emanating from the massive central black hole of M87.
Black Holes Shed Light on Galaxy Formation
June 5, 2000 press release and related information from the Space Telescope Science Institute.
Feasting Black Hole Blows Bubbles
June 5, 2000 press release and related information from the Space Telescope Science Institute.
Lone Black Holes Discovered Adrift in the Galaxy
January 13, 2000 press release and related information from the Space Telescope Science Institute.
Black holes once ruled the universe
March 2001 news article about abundance of black holes revealed by a Chandra x-ray telescope deep field survey.

Recommended references: Magazine/journal articles

Goldilocks Black Holes
Jenny E. Greene
Scientific American, January 2012, pp. 40-47
Tipping the scales at less than about a million suns in mass, middleweight black holes may hold clues to how their much larger siblings, and galaxies, first formed.
Black hole silhouettes
Charles Petit
Science News, October 9, 2010
Scientists attempt to image a shadow and its tumultuous ring.
How Quantum Effects Could Create Black Stars, Not Holes
Carlos Barceló, Stefano Liberati, Sebastiano Sonego; Matt Visser
Scientific American, October 2009
Quantum effects may prevent true black holes from forming and give rise instead to dense entities called black stars.
Do Naked Singularities Break the Rules of Physics?
Pankaj S. Joshi
Scientific American, January 2009
Ultramassive: As Big As It Gets
Charles Petit
Science News, October 25, 2008
An Echo of Black Holes
Theodore A. Jacobson; Renaud Parentani
Scientific American, December 2005
Quantum Black Holes
Bernard J. Carr; Steven B. Giddings
Scientific American, May 2005
The Hole Story
Ron Cowen
Science News, January 22, 2005
Black Hole Computers
Seth Lloyd; Y. Jack Ng
Scientific American, November 2004
Hawking a Theory
Graham P. Collins
Scientific American, October 2004
The Galactic Odd Couple
Kimberly Weaver
Scientific American, July 2003,
Is the black hole information paradox solved?
Jet Astronomy
Ron Cowen
Science News, November 9, 2002, pp. 299-300
Jets of high-speed particles are common to various astronomical objects, such as pulsars, stellar-scale black holes, and massive black holes. New X-ray observations of jets associated with small black holes are making possible a better understanding of the general process.
Beyond Black
Ray Jayawardhana
Astronomy, June 2002, pp. 28-33
There is extensive circmustantial evidence for the existence of black holes. But specific proof "beyond a reasonable doubt" for their existence has been surprisingly difficult to come by.
The Black Hole Next Door
Peter Weiss
Science News, March 23, 2002, pp. 187-188
If some theories of extra spatial dimensions are correct, microscopic black holes could form from collisions of subatomic particles in very high energy cosmic rays or in particles produced in the next generation of particle accelerators.
Get the Hole Story
Neil F. Comins
Astronomy, April 2001, pp. 48-53
Elementary overview article.
Revisiting the Black Hole
Roger Blandford, Neils Gehrels
Physics Today, June 1999, pp. 40-46
Until very recently the main objective of research on black holes has been to prove their existence. Now that this is virtually certain, the objective has shifted to making detailed predictions and observations of black hole behavior
Black Hole Hunters
Steve Olson
Astronomy, May 1999, pp. 48-55
Massive black holes at the centers of most galaxies appear to play a large role in the development of the host galaxy.
Unmasking Black Holes
Jean-Pierre Lasota
Scientific American, May 1999, pp. 40-47
Until recently the evidence for existence of black holes was strong but only circumstantial. New observations now require the existence of black holes with their characteristic event horizons and unambiguously distinguish black holes from neutron stars.
A Beast in the Core
Marcia Bartusiak
Astronomy, July 1998, pp. 42-47
Supermassive black holes may occur at the center of most large galaxies. They may be the remnants of a quasar phase earlier in the life of the galaxies.
To the Edge of Space and Time
Martin Rees
Astronomy, July 1998, pp. 48-53
The physics of black holes was both predicted and described by various solutions of the equation of general relativity.
Does a Monster Lurk Closeby?
Bonnie Schulkin
Astronomy, September 1997, pp. 42-47
Recent evidence points towards the existence of a supermassive black hole at the center of the Milky Way.
Black Holes and the Information Paradox
Leonard Susskind
Scientific American, April 1997, pp. 52-57
The information paradox is a conflict between the apparent loss of information when matter is consumed by a black hole and conservation requirements of quantum theory. Resolution of the paradox may facilitate a quantum theory of gravity.
Black Holes, Naked Singularities, and Cosmic Censorship
Stuart L. Shapiro; Saul A. Teukolsky
American Scientist, July-August 1991, pp. 330-343
The cosmic censorship hypothesis of Roger Penrose states that singularities of the general theory of relativity must always be concealed within the event horizon of a black hole. Determining the validity of this hypothesis is one of the most important problems in general relativity. Computer simulation experiments cast doubt on the hypothesis.
The Membrane Paradigm for Black Holes
Richar H. Price; Kip Thorne
Scientific American, April 1988, pp. 69-77
The physics of the interaction between black holes and their environment seems like it must be quite exotic. However, a great deal can be understood by regarding a black hole as an electrically conducting, spheroidal membrane.
The Birth of Neutron Stars and Black Holes
Adam Burrows
Physics Today, September 1987, pp. 28-37
Theory indicates that stars more than 6 to 8 times the mass of the Sun cannot end their lives as white dwarves but must instead explode as supernovae. The final result of such an event is usually a neutron star or a black hole, but the exact conditions leading to one or the other are uncertain.
The Quantum Mechanics of Black Holes
S. W. Hawking
Scientific American, January 1977, pp. 34-40
It has long been assumed that nothing, not even light, can escape from a black hole. But now it appears that matter can indeed escape by a process like quantum tunneling, and a black hole can even "evaporate" completely.

Recommended references: Books

Leonard Susskind; James Lindesay – An Introduction to Black Holes, Information, and the String Theory Revolution: The Holographic Universe
World Scientific Publishing Co., 2005
This is a relatively short book that covers a lot of ground and is intended for readers who have had at least an introductory course in quantum mechanics. Part I reviews basic background material on the mathematical theory of black holes and related quantum mechanics. Part II covers entropy bounds and holography as they relate to black holes. Part III deals with the use of string theory to calculate black hole entropy, following Bekenstein and Hawking.
Derek Raine; Edwin Thomas – Black Holes: An Introduction
Imperial College Press, 2005
As the subtitle promises, this book is an introduction, though not an elementary one, with plenty of math and physics in its 150 pages. The major topics are spherically symmetric (the simplest) and rotating black holes, thermodynamics of black holes, and (a little bit about) astrophysical black holes.
Edwin F. Taylor; John Archibald Wheeler -- Exploring Black Holes: Introduction to General Relativity
Addison Wesley Longman, 2000
The authors are masters of the subject. (Wheeler coined the term "black hole".) The present book is a mathematical introduction to general relativity which is developed around the theory of black holes. However, it is a gentle introduction which uses little more than calculus and does not develop the theory in full generality.
Mitchell Begelman; Martin Rees - Gravity's Fatal Attraction: Black Holes in the Universe
Scientific American Library, 1998
This attractive and colorfully illustrated volume, full of graphs, diagrams, and astrophotos, provides a nontechnical overview of our knowledge of black holes. Topics include how black holes form, phenomena which occur in the vicinity of a black hole, massive black holes in galaxies, and observational evidence.
Robert M. Wald, ed. – Black Holes and Relativistic Stars
University of Chicago Press, 1998
Consists of 12 papers, by leading experts in the field, collected for a symposium in honor of S. Chandrasekhar. Authors include Thorne, Rees, Penrose, Hartle, and Hawking. The material is mostly theoretical rather than observational. Although the volume is written for professionals, much of it is useful for seriously interested amateurs.
Kitty Ferguson - Prisons of Light: Black Holes
Cambridge University Press, 1996
Relatively brief, non-technical survey of black hole theory and summary of observational evidence of the existence of black holes.
Clifford Pickover - Black Holes: A Traveler's Guide
John Wiley & Sons, 1996
Brief, entertaining, and quirky melange of information on black holes. Has an interesting survey of specialist opinions on the subject, and simple computer programs in C and Basic for a few elementary calculations.
Kip S. Thorne - Black Holes & Time Warps: Einstein's Outrageous Legacy
W. W. Norton & Company, 1994
Thorne is one of the chief authorities in this field, and this book is a definitive, non-mathematical exposition. It concludes with speculations on the possibilities of wormholes and time travel. Good glossary and biblography. Easily the best choice as an introduction, if you have the time.
John Gribbin - Unveiling the Edge of Time: Black Holes, White Holes, Wormholes
Harmony Books, 1992
Introduction to black holes, together with more speculative material on "white holes", "wormholes", and time travel.
Jean-Pierre Luminet - Black Holes
Cambridge University Press, 1992 (translation), 1987 (original)
Good general survey of black hole theory by a specialist in the subject. Topics include supernovae, pulsars, white holes, quantum black holes, primordial black holes.


Copyright © 2002 by Charles Daney, All Rights Reserved