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11/6/2012 Black holes are found in space. Once you get past the horizon on a black hole, you can never escape. You would be sucked in, and then die. At the bottom of a black hole is a “ball”, called a singularity. A black hole is invisible. The reason a black hole is invisible is because if light gets near a black hole it gets sucked in and can never escape. It has a super strong gravitational pull. Black holes form when stars die. Stars will take billions of years to die. When all the hydrogen in a star burns up, the star dies. Before the star died, heat was pushing out of the star while gravity was pushing in on the star. When there was no more hydrogen, no more heat was pushing out of the star, but gravity was still pushing in on the star. A star will cave in on itself so the star will get smaller and denser. Because the stars material is packed in a tiny space, the gravity is much stronger. Three concepts that scientists need to study black holes are gravity, escape velocity, and the speed of light. Light can travel at 186,282 miles per second. Light has the highest escape velocity in the universe. Even it can’t escape a black hole. The only way to escape a black hole is to reach an escape velocity faster than the speed of light, but this is impossible. So gravity makes black holes. Black holes are not really holes, more like a funnel. Only very large stars could become a black hole. In order for our sun to become a black hole, it would have to be at least ten times bigger than it is now. Scientists use special telescopes that can detect X-rays. The best way to study black holes is to study binary stars. Binary stars are two stars that obit each other. If a star looks like it is orbiting empty space, there might be a black hole there. Fast Fact: White holes are the exact opposite of black holes Super massive black holes first got thought up when scientists thought stars in the center of the galaxy were circling something. Possibly a black hole? If it is, only a super massive black hole could do it. Scientists believe super massive black holes are at the center of most galaxies. One way they could have been made was stars in the center of the galaxy could have died, forming black holes. Then those black holes were so close, that they sucked in one another, forming a super massive black hole. Most scientists think that there are super massive black holes at the center of most galaxies. 1 11/6/2012 In 1930, scientists started to believe black holes existed. But the late 1700’s is when the study of space objects with strong gravity started. Pierre La Place tried to use math to explain black holes. He lived from 1749-1827. Stephen Hawking; an English scientist, is famous for researching black holes. He has written some popular books on black holes; explaining that black holes might be how our universe came to be. Black holes are one of the most mysterious things in space. Even though they are invisible, we are still able to study them. Also, technology is advancing rapidly. Black holes are extremely interesting, and there will always be more to learn about them, since they are so different than anything else in space. Fast Fact: Don’t worry about a black hole ending Earth. Chances of that are slim to none. BLACK HOLE INTERNET LINKS http://cosmology.berkeley.edu/Education/BHfaq.html by: Tedd Bunn http://imagine.gsfc.nasa.gov/docs/science/know_l2/black_holes.html by: Phil Newman http://amazing‐ space.stsci.edu/resources/explorations/blackholes/lesson/whatisit/index.html by: unknown 2