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Black Holes

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Black Holes Albert Einstein first predicted black holes in 1916 with his general theory of relativity. The term "black hole" was coined in 1967 by American astronomer John Wheeler, and the first one was discovered in 1971. A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying. Because no light can get out, people can't see black holes. They are invisible. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently than other stars. Scientists think the smallest black holes formed when the universe …show more content…

It's about four million times the mass of the Sun. It's surrounded by a cluster of young stars, some of which plunge to within a few billion miles of the black hole. And although it's quiet today, a century ago it gorged on a clump of matter that passed too close, creating a pyrotechnic display that lit up the Milky Way's heart. Much of that evidence has been amassed by two teams, one led by Ghez and another by Reinhard Genzel, director of the Max Planck Institute for Extraterrestrial Physics in Germany. Using giant telescopes in Hawaii and Chile and cutting-edge observational techniques, they have probed closer to the black hole than ever before. That has allowed them to plot the orbits of giant stars that pass hair-raisingly close to the black hole, providing the best measurement of the black hole's mass. And it has revealed that some of the stars around the black hole are far younger than expected. "There's been a myriad of surprises, which is the fun of doing research," says Ghez. "You go in expecting to answer one thing and you come out the other end with more questions than you started with." The central question that Ghez, Genzel, and others hoped to answer was whether a supermassive black hole inhabits the center of the Milky Way. As early as 1980, radio observations revealed that gas was swirling around a dark, massive object at the center of the galaxy. That object, which glowed steadily at radio

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