1. HubbleSite: Black Holes: Gravity's Relentless Pull Black Holes Gravity's Relentless Pull. Information, virtual journeys, and simulations about black holes from the Space Telescope Science Institute http://hubblesite.org/explore_astronomy/black_holes/

2. StarChild: Black Holes Guess what? Some scientists believe that there is a black hole here in our very own Milky Way. http://starchild.gsfc.nasa.gov/docs/StarChild/universe_level2/black_holes.html

Black Holes Guess what? Some scientists believe that there is a black hole here in our very own Milky Way. Black holes are extremely compact space objects that were once massive stars which collapsed inward due to the force of their own gravity . Consequently, black holes are very dense. If it were not for the effect that black holes have on the objects around them, we would be unable to detect them. A black hole has a powerful gravitational field which traps everything that goes near it. Scientists now theorize that some galaxies have huge black holes in their centers which release tremendous amounts of energy that powers the spectacular energetic events that go on within the galaxy. The fuel for the black hole, scientists believe, may be the trapped gas, stars, and dust that are pulled into the hole. Gas that is pulled into a black hole swirls down into the hole much like a whirlpool. By using a spectroscope , the Hubble Space Telescope has the ability to clock the speed of this gas as it swirls around the entrance to the hole. The speed with which the gas swirls is considered the black hole's signature. By knowing the speed of the gas, the mass of the black hole can be calculated.

3. Black Holes This site is intended for students age 14 and up, and for anyone interested in learning about our universe. http://imagine.gsfc.nasa.gov/docs/science/know_l2/black_holes.html

What's New Site Map NASA Homepage Search: ... Advanced Science Current Page Additional Links "Quiz Me!" about this topic! Cool Fact about this topic! Try This! FAQs on Black Holes ... Give Me additional resources! Related Topics Supernovae X-ray Binaries Neutron Stars and Pulsars White Dwarfs ... Black Holes May Take Space For a Spin For Educators Black Holes Booklet The Life Cycle of Stars Booklet Show me related lesson plans Black Holes NOTE: This section is about what are called "stellar-mass black holes". For information about black holes with the mass of billions of Suns, see There are many popular myths concerning black holes , many of them perpetuated by Hollywood. Television and movies have portrayed them as time-traveling tunnels to another dimension, cosmic vacuum cleaners sucking up everything in sight, and so on. It can be said that black holes are really just the evolutionary end point of massive stars . But somehow, this simple explanation makes them no easier to understand or less mysterious. Black Holes: What Are They?

4. Black Holes - Scholarpedia Figure 1 Artist's conception of an accretion disk around a black hole. Credit NASA/CXC/M.Weiss. http://www.scholarpedia.org/article/Black_holes

Black holes From Scholarpedia Teviet Creighton and Richard H. Price (2008), Scholarpedia, 3(1):4277. doi:10.4249/scholarpedia.4277 revision #73227 [ link to/cite this article Jump to: navigation search Curator: Dr. Teviet Creighton, University of Texas, Brownsville, TX Curator: Dr. Richard H. Price, University of Texas, Brownsville, TX Figure 1: Artist's conception of an accretion disk around a black hole. Credit: NASA /CXC/M.Weiss. Black Holes are regions of space in which gravitational fields are so strong that no particle or signal can escape the pull of gravity. The boundary of this no-escape region is called the event horizon, since distant observers outside the black hole cannot see (cannot get light from) events inside. Although the fundamental possibility of such an object exists within Newton's classical theory of gravitation, Einstein's theory of gravity makes black holes inevitable under some circumstances. Prior to the early 1960s black holes seemed to be only an interesting theoretical concept with no astrophysical plausibility, but with the discovery of quasars in 1963 it became clear that very exotic astrophysical objects could exist. Nowadays it is taken for granted that black holes do exist in at least two different forms. Stellar mass black holes are the endpoint of the death of some stars, and supermassive black holes are the result of coalescences in the centers of most galaxies, including our own. No signal can propagate from inside a black hole, but the gravitational influence of a black hole is always present. (This influence does not

5. ScienceDaily: Black Hole News Black Holes in Space. Read science articles on colliding supermassive black holes, simulated gravitational waves of a black hole, black hole theory and more. Astronomy images. http://www.sciencedaily.com/news/space_time/black_holes/

Black Hole News Sunday, November 14, 2010 Print Email Bookmark Latest News Astronomy Astronomy Black Holes Cosmic Rays Dark Matter ... Stars Cosmology Astrophysics Big Bang Cosmology Solar System Asteroids, Comets and Meteors Jupiter Kuiper Belt Mars ... Xena Space Exploration ESA NASA Satellites Space Exploration ... Books RSS NASA's Fermi Telescope Finds Giant Structure in Our Galaxy full story Simulating Black Hole Radiation With Lasers: Lasers Produce the First Hawking Radiation Ever Detected full story ... Neutron Stars May Be Too Weak to Power Some Gamma-Ray Bursts; Black Holes May Be Power Source Browse News Stories 1 to 10 of 388 stories (52 over past year) view headlines only Galaxies Astronomy Stars ... Precocious Galaxy Cluster Identified by Chandra October 28, 2010 full story Stars Black Holes Astronomy ... Star, Not So Bright: Model Explains Evolution of Unusual Black Hole Binary System October 21, 2010 full story Black Holes Cosmic Rays Space Telescopes ... Gigantic Mirror for X-Radiation in Outer Space September 27, 2010 full story Black Holes Galaxies Astrophysics ... Extreme X-Ray Source Suggests New Class of Black Hole September 9, 2010 full story Galaxies Astrophysics Black Holes ... When Galaxies Collide: How the First Super-Massive Black Holes Were Born August 26, 2010

6. Space.com : Black Holes: Warping Time & Space When a supermassive star dies, it When a super-massive star dies, it's corpse collapses into a knot so tight not even light can escape. http://www.space.com/common/media/video/player.php?videoRef=black_holes

7. Black Holes - Crystalinks Black Holes. Simulation A black hole is a star that has collapsed into a tiny point known as a singularity. It is so dense that it sucks in everything near it, including light. http://www.crystalinks.com/black_holes.html

Black Holes Simulation A black hole is a star that has collapsed into a tiny point known as a singularity. It is so dense that it sucks in everything near it, including light. Black holes can be seen via the death throes of the matter being sucked in. Although it becomes invisible past a certain point, an accretion disk, which is visible, develops as the matter swirls toward the black hole. The collapsed star is so dense that nothing can escape its gravitational pull, not even light. A black hole is a concentration of mass great enough that the force of gravity prevents anything from escaping from it except through quantum tunneling behavior. The gravitational field is so strong that the escape velocity near it exceeds the speed of light. This implies that nothing, not even light, can escape its gravity, hence the word "black." The term "black hole" is widespread, even though it does not refer to a hole in the usual sense, but rather a region of space from which nothing can return. Theoretically, black holes can have any size, from microscopic to near the size of the observable universe. Black holes are predicted by general relativity. According to classical general relativity, neither matter nor information can flow from the interior of a black hole to an outside observer. For example, one cannot bring out any of its mass, or receive a reflection back by shining a light source such as a flashlight, or retrieve any information about the material that has entered the black hole. Quantum mechanical effects may allow matter and energy to radiate from black holes; however, it is thought that the nature of the radiation does not depend on what has fallen into the black hole in the past.

8. StarChild: Black Holes What is a black hole and how do we know it exists?(for K-4th graders) http://starchild.gsfc.nasa.gov/docs/StarChild/universe_level1/black_holes.html

Listen Black Holes Most scientists believe that there is a black hole in the center of our very own Milky Way. Black holes were once massive stars that used up all their fuel . As they died out, they collapsed inward due to the pull of their own gravity . The gravity of a black hole is so powerful that not even light can escape its pull! Once any matter falls into a black hole, it disappears from the visible universe It is very hard to see a black hole. Any object that gets too close to a black hole will be pulled inside it. We only know they are there because of the effects they have on other objects that are near them. Any object, whether some dust, or a star, or anything, that gets too close to a black hole will be pulled inside it. As the objects fall toward the black hole, they heat up and get very hot. Scientists can use special instruments to detect the heat the objects give off. That is how we know the black hole must be there. A Question How do we know that there really are black holes? Show me the Level 2 version of this page.

9. Gothos: Jillian's Guide To Black Holes Introduction to the types, formation, and environment inside and outside of black holes. http://www.gothosenterprises.com/black_holes/

Jillian's Guide to Black Holes An informal introduction to black holes, those wacky astronomical oddities of extremity! Loosely affiliated with the slightly less well-known Jillian's Guide to Gravitational Waves How to create a black hole, using stars, matter from a split-second after the big bang, and other household items. Three classifications of black holes, a breakdown of their parts, and descriptions of what happens at varying distances from a black hole. Why black holes are most often seen with accretion disks, Hawking radiation, and how one can steal energy from a rotating black hole. ... Other interesting and informative websites Organization, Caveats, and Editor's Notes I wrote this web site because I have always liked learning about black holes. However, it was always a challenge finding reading material that did not go over my head. I created this web site as a resource that I wish I had had access to when I wanted to learn about black holes. The information covered here is just the tip of the iceberg, an introduction to the wacky and wonderful world of relativity and astronomy. I would stress that this is difficult material. The best way to understand black holes and relativity better is to bone up on your math skills and take a course in relativity. The math is a tool you need to really understand this material. Give yourself time to learn - do not expect to pick this up in a week.

10. Ask An Astrophysicist: Black Holes Commonly-asked questions, and a way to ask an astronomer a question about black holes. http://imagine.gsfc.nasa.gov/docs/ask_astro/black_holes.html

What's New Site Map NASA Homepage Search: ... Ask an Astrophysicist Current page Relativity Binary Star Systems Resources for this Topic How Do We See Black Holes? Virtual Trip to a Black Hole Black Hole Frequently Asked Questions Usenet Physics Frequently Asked Questions List ... Imagine the Universe! Black Holes Library of Past Questions Black Holes First time visitors: Please be sure to read our main page Check out the resource links. These are the sites we often point to in answering your questions. Browse through the library of questions below. Also try our Ask an Astrophysicist Search Engine! If your question is still not answered, follow the link at the bottom of this page Library of Past Questions and Answers Common Questions about Black Holes How many black holes are currently known? Where is, and how far is the nearest known Black Hole? Is it true that time stops at the Event Horizon? If light has no mass, how can it get trapped in a Black Hole? ... Can black holes/worm holes transport you to other worlds? Evidence for Black Holes Who was the first person to discover a black hole and what was the date?

11. Black Holes - Introduction This site is intended for students age 14 and up, and for anyone interested in learning about our universe. http://imagine.gsfc.nasa.gov/docs/science/know_l1/black_holes.html

What's New Site Map NASA Homepage Search: ... Science Current Page Additional Links "Quiz Me!" about this topic! Cool Fact about this topic! Try This ! FAQs on Black Holes ... Give Me additional resources! Related Topics Supernovae X-ray Binaries Active Galaxies The Hole Story? New Type of Black Hole Poses Challenges ... ASD Podcast Featuring X-rays and Black Holes For Educators Black Holes Booklet The Life Cycles of Stars Booklet Show me related lesson plans Animation of a Black Hole Black Holes Introduction to Black Holes Black holes are objects so dense that not even light can escape their gravity , and since nothing can travel faster than light, nothing can escape from inside a black hole. On the other hand, a black hole exerts the same force on something far away from it as any other object of the same mass would. For example, if our Sun was magically crushed until it was about 1 mile in size, it would become a black hole, but the Earth would remain in its same orbit Even back in Isaac Newton 's time, scientists speculated that such objects could exist, even though we now know they are more accurately described using Einstein 's General Theory of Relativity . Using this theory, black holes are fascinating objects where space and time become so warped that time practically stops in the vicinity of a black hole.

12. Micro Black Hole - Wikipedia, The Free Encyclopedia Micro black holes are tiny black holes, also called quantum mechanical black holes or mini black holes, for which quantum mechanical effects play an important role. http://en.wikipedia.org/wiki/Micro_black_holes

Micro black hole From Wikipedia, the free encyclopedia   (Redirected from Micro black holes Jump to: navigation search MBH redirects here. It can also refer to the Hayist Bases Movement , or a unit of power - a thousand BTUs per hour. Micro black holes are tiny black holes , also called quantum mechanical black holes or mini black holes , for which quantum mechanical effects play an important role. It is possible that such quantum primordial black holes were created in the high-density environment of the early Universe (or big bang ), or possibly through subsequent phase transitions. They might be observed by astrophysicists in the near future, through the particles they are expected to emit by Hawking radiation Some theories involving additional space dimensions predict that micro black holes could be formed at an energy as low as the TeV range, which will be available in particle accelerators such as the LHC ( Large Hadron Collider ). Popular concerns have then been raised over end-of-the-world scenarios (see Safety of particle collisions at the Large Hadron Collider ). However, such quantum black holes would instantly evaporate, either totally or leaving only a very weakly interacting residue. Beside the theoretical arguments, we can notice that the

13. Black Holes Information about the astrophysics of black holes on the website of NASA s High-Energy Astrophysics Learning Center. Suitable for ages 14 and up. http://imagine.gsfc.nasa.gov/docs/introduction/black_holes.html

What's New Site Map NASA Homepage Search: ... Feedback Black Holes Level 1 topics include: Introduction to Black Holes Journey into a Black Hole! Level 2 topics include: Black Holes: What Are They? If We Can't See Them, How Do We Know They're There? What About All the Wormhole Stuff? Take Me to Level 1 Information Take Me to Level 2 Information Home Imagine Science ... Ask an Astrophysicist If words seem to be missing from the articles, please read this Imagine the Universe! is a service of the High Energy Astrophysics Science Archive Research Center ( HEASARC ), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center The Imagine Team Project Leader: Dr. Jim Lochner Curator: Meredith Gibb Responsible NASA Official: Phil Newman All material on this site has been created and updated between 1997-2010. Last Updated: Tuesday, 04-Dec-2001 15:46:56 EST Useful plugins Do you have a question, problem or comment about this web site? Please let us know External links contain material that we found to be relevant. However they're not maintained by us and the content may have changed. If you find any external links that contain inappropriate material, please let us know!

14. APOD Index - Stars: Black Holes From NASA s Astronomy Picture of the Day archive, the three most educational images (editor s choice) related to black holes. http://antwrp.gsfc.nasa.gov/apod/black_holes.html

Astronomy Picture of the Day Index - Stars: Black Holes Today's APOD Title Search Text Search Editor's choices for the most educational Astronomy Pictures of the Day about black holes: APOD: 1997 January 15 – Black Hole Signature From Advective Disks Explanation: What does a black hole look like? If alone, a black hole would indeed appear quite black, but many black hole candidates are part of binary star systems . So how does a black hole binary system look different from a neutron star binary system ? The above drawings indicate it is difficult to tell! Recent theoretical work , however, has provided a new way to tell them apart: advective accretion flows (ADAFs) . A black hole system so equipped would appear much darker than a similar neutron star system. The difference is caused by the hot gas from the ADAF disk falling through the event horizon of the black hole and disappearing - gas that would have emitted much light were the central object only a neutron star. Recent observations of the soft X-ray transient V404 Cyg has yielded a spectrum much like an ADAF onto a black hole - and perhaps brighter than allowable from an ADAF onto a neutron star.

15. Black Holes Basic ideas of black hole physics, plus some more advanced material about astrophysical and quantum-gravity aspects; based on lectures given as part of a course Foundations of Physics I by Gabor Kunstatter at the University of Winnipeg in 2002. http://theory.uwinnipeg.ca/users/gabor/black_holes/

16. BLACK HOLES By Ted Bunn List of questions that explore the basic properties of black holes (such as what happens when you fall in, or how a black hole evaporates). http://cosmology.berkeley.edu/Education/BHfaq.html

B lack H oles FAQ (F requently A sked Q uestions L ist by Ted Bunn What is a black hole? How big is a black hole? What would happen to me if I fell into a black hole? My friend Penelope is sitting still at a safe distance, watching me fall into the black hole. What does she see? ... Where can I go to learn more about black holes? What is a black hole? Loosely speaking, a black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull. Since our best theory of gravity at the moment is Einstein's general theory of relativity, we have to delve into some results of this theory to understand black holes in detail, but let's start of slow, by thinking about gravity under fairly simple circumstances. Now imagine an object with such an enormous concentration of mass in such a small radius that its escape velocity was greater than the velocity of light. Then, since nothing can go faster than light, nothing can escape the object's gravitational field. Even a beam of light would be pulled back by gravity and would be unable to escape. The idea of a mass concentration so dense that even light would be trapped goes all the way back to Laplace in the 18th century. Almost immediately after Einstein developed general relativity, Karl Schwarzschild discovered a mathematical solution to the equations of the theory that described such an object. It was only much later, with the work of such people as Oppenheimer, Volkoff, and Snyder in the 1930's, that people thought seriously about the possibility that such objects might actually exist in the Universe. (Yes, this is the same Oppenheimer who ran the Manhattan Project.) These researchers showed that when a sufficiently massive star runs out of fuel, it is unable to support itself against its own gravitational pull, and it should collapse into a black hole.

17. Black Hole - Wikipedia, The Free Encyclopedia Black holes saturating this inequality are called extremal. Solutions of Einstein's equations violating the inequality exist, but do not have a horizon. http://en.wikipedia.org/wiki/Black_hole

Black hole From Wikipedia, the free encyclopedia Jump to: navigation search For other uses, see Black hole (disambiguation) Simulated view of a black hole in front of the Large Magellanic Cloud . The ratio between the black hole Schwarzschild radius and the observer distance to it is 1:9. Of note is the gravitational lensing effect known as an Einstein ring , which produces a set of two fairly bright and large but highly distorted images of the Cloud as compared to its actual angular size. General relativity Einstein field equations Introduction Mathematical formulation ... Resources Fundamental concepts Special relativity Equivalence principle World line Riemannian geometry Phenomena Kepler problem Lenses Waves Frame-dragging ... Singularity Black hole Equations Linearized Gravity Post-Newtonian formalism Einstein field equations Friedmann equations ... BSSN formalism Advanced theories Kaluza–Klein Quantum gravity Solutions Schwarzschild ... pp-wave Scientists Einstein Minkowski Eddington Lemaître ... e A black hole is a region of space from which nothing, not even light , can escape. It is the result of the deformation of

18. Virtual Trips To Black Holes And Neutron Stars Page s and MPEG movies based on general relativistic simulations of black holes What will an observer see close to a black hole, or in the neighborhood of a neutron star...... http://antwrp.gsfc.nasa.gov/htmltest/rjn_bht.html

Virtual Trips to Black Holes and Neutron Stars by Robert Nemiroff ( Michigan Technological University Ever wonder what it would look like to travel to a black hole? A neutron star? If so, you might find this page interesting. Here you will find descriptions and MPEG movies that take you on such exciting trips. These movies are scientifically accurate computer animations made with strict adherence to Einstein's General Theory of Relativity. The descriptions are written to be understandable on a variety of levels - from the casually curious to the professionally inquisitive. It is hoped that students from grade school to graduate school will find these virtual trips educational. "A stimulating, relativistically accurate trip!" - Kip Thorne The Feynman Professor of Theoretical Physics, California Institute of Technology, Author of "Black Holes and Time Warps - Einstein's Outrageous Legacy" Earth if compressed to ultracompact density and viewed from the photon sphere. Written Description of Visible Distortion Effects Below is a published paper understandable to undergraduates: "Visual Distortions Near a Black Hole and Neutron Star," Nemiroff, R. J. 1993, American Journal of Physics, 61, 619

19. Black Holes Questions and Answers about Black Holes 1. Is it possible for black holes to lead to other universes? Using black holes to get from one place to another is an interesting story. http://www.astro.umd.edu/~miller/teaching/questions/blackholes.html

Questions and Answers about Black Holes 1. Is it possible for black holes to lead to other universes? Cole Miller 2. What happens to all the stuff that get's sucked into the black hole? Would it pop out randomly at some other place or something? Or would things not survive a black hole? It is thought that the matter that goes into a black hole gets crushed into a tiny point at the center called a "singularity".  That's the only place that matter is, so if you were to fall into a black hole you wouldn't hit a surface as you would with a normal star.  Once it's there, it's there.  As far as we know, nothing would survive going into a black hole.  People sometimes talk about "wormholes" as portals to other universes, but it is now thought to be very likely that these can't exist. Cole Miller 3. If nothing escapes a black hole not even light, and  if gravity is perhaps a form of electromagnetic radiation (G.U.T.) how does gravity escape the black hole to pull things in? The idea (in Einstein's conception) is that space and time are parts of one entity, spacetime. The presence of mass distorts and warps this spacetime; normally the warping is minor, but around a very compact object such as a black hole or a neutron star the warping is dramatic and all sorts of funky effects happen.  A good analogy to think of is a heavy ball on a rubber sheet. The ball distorts the sheet, so if something light rolls by its path is deflected.  Net result: the light thing curves, which is the normal expected effect of gravity.  Therefore, the key is that the effect of gravity does not emanate from inside the black hole; instead, it comes from the overall warping of spacetime *outside* the hole.

20. HowStuffWorks "How Black Holes Work" What are black holes? Do they really exist? How can we find them? Article by Craig C. Freudenrich. http://www.howstuffworks.com/black-hole.htm

HSW.sm.loadPageInfo(6914); OAS_AD('TopBanner'); HowStuffWorks Search HowStuffWorks and the web Video Podcasts Blogs Quizzes Games RSS Adventure Animals Auto Culture ... Next Page How Black Holes Work by Craig Freudenrich, Ph.D. Print Cite Feedback ... Recommend Cite This! Close Please copy/paste the following text to properly cite this HowStuffWorks article: Inside this Article Introduction to How Black Holes Work What is a Black Hole? Types of Black Holes How We Detect Black Holes ... See all Astronomy Terms articles The Space Shuttle Videos Black Hole Image Gallery Photo courtesy NASA/Space Telescope Science Institute (J. Gitlin, artist) Artist concept of the near vicinity of the black hole at the core of galaxy NGC 4261. See more black hole images You may have heard someone say, "My desk has become a black hole!" You may have seen an astronomy program on television or read a magazine article on black holes. These exotic objects have captured our imagination ever since they were predicted by Einstein's Theory of General Relativity in 1915.

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