Black holes, when imagined, are unimaginable. But popular culture got used to them anyway. Black holes are the stars of movies, the heroes of books, and the byword for all kinds of bad risks. They are over familiar and all but cliché. Luckily, astronomers are not bored yet. In the last few years, they have found increasing evidence of black holes both in our galaxy and outside it. These days, what’s most unbelievable about black holes is that they seem to be real.
For certain stars, black holes are the afterlife. Stars the size of our sun spend their lives burning fuel and radiating light, balancing the radiation’s push outward against gravity’s pull inward. As a star runs out of fuel, gravity begins to win. The star condenses and shrinks smaller and smaller until gravity’s pull again balanced, this time by the force that deeps electrons from crowding too close together. The star, now called a white dwarf, shines for a while, then gradually cools and dims.
In stars with masses more than eight times the sun’s, gravity is correspondingly stronger. These stars die with a bang in supernova explosions, which blow away much of the star’s mass. If what remains is less then three solar masses, gravity jams the negatively charged electrons and the positively charged protons together. The opposite charges neutralize each other, and the remnant core, now composed entirely of neutrons, is called a neutron star. It has shrunk to about ten miles in diameter. Matter this compact “beggars description," says Jeffrey McClintock, an astronomer at the Harvard-Smithsonian Center for astrophysics in Massachusetts. If the Great Lakes were made this compact, they would fit into a bathroom sink. “Compact is the word we like to use,” McClintock adds, "because dense doesn’t even cover it." Neutron stars shine when they’re formed, most brightly in X rays; they also have magnetic field that can send out crisp pulses of radio waves.
In stars with masses forty times the sun’s, gravity is strong enough to make the unthinkable happen. These stars also die violently. If the remaining core is bigger than a neutron star-that is, greater than three solar masses - it condenses to nothingness, or near enough to make no difference. Physicists call this point a singularity and tend not to talk about it because they have no clue as to what happens to matter at these densities. "it most likely goes unstable," says McClintock. “Does it exist anymore? I don’t know. It’s basically out the window. The elementary particles themselves are turn into a fragment whose nature is not known and cannot be guessed.” Scientists do know that matter at these densities loses all properties except for mass, rotation, and charge. Says McClintock: “The trees out there, those pearls, the computer- any property they have, once in the black hole- they don’t have anymore.” The physicists’ phrase is “black holes have no hair.” “That means black holes don’t have you-name-it, just-list-it,” says McClintock. “Nothing nothing nothing nothing.”
Black holes, when imagined, are unimaginable. But popular culture got used to them anyway. Black holes are the stars of movies, the heroes of books, and the byword for all kinds of bad risks. They are over familiar and all but cliché. Luckily, astronomers are not bored yet. In the last few years, they have found increasing evidence of black holes both in our galaxy and outside it. These days, what’s most unbelievable about black holes is that they seem to be real.
For certain stars, black holes are the afterlife. Stars the size of our sun spend their lives burning fuel and radiating light, balancing the radiation’s push outward against gravity’s pull inward. As a star runs out of fuel, gravity begins to win. The star condenses and shrinks smaller and smaller until gravity’s pull again balanced, this time by the force that deeps electrons from crowding too close together. The star, now called a white dwarf, shines for a while, then gradually cools and dims.
In stars with masses more than eight times the sun’s, gravity is correspondingly stronger. These stars die with a bang in supernova explosions, which blow away much of the star’s mass. If what remains is less then three solar masses, gravity jams the negatively charged electrons and the positively charged protons together. The opposite charges neutralize each other, and the remnant core, now composed entirely of neutrons, is called a neutron star. It has shrunk to about ten miles in diameter. Matter this compact “beggars description," says Jeffrey McClintock, an astronomer at the Harvard-Smithsonian Center for astrophysics in Massachusetts. If the Great Lakes were made this compact, they would fit into a bathroom sink. “Compact is the word we like to use,” McClintock adds, "because dense doesn’t even cover it." Neutron stars shine when they’re formed, most brightly in X rays; they also have magnetic field that can send out crisp pulses of radio waves.
In stars with masses forty times the sun’s, gravity is strong enough to make the unthinkable happen. These stars also die violently. If the remaining core is bigger than a neutron star-that is, greater than three solar masses - it condenses to nothingness, or near enough to make no difference. Physicists call this point a singularity and tend not to talk about it because they have no clue as to what happens to matter at these densities. "it most likely goes unstable," says McClintock. “Does it exist anymore? I don’t know. It’s basically out the window. The elementary particles themselves are turn into a fragment whose nature is not known and cannot be guessed.” Scientists do know that matter at these densities loses all properties except for mass, rotation, and charge. Says McClintock: “The trees out there, those pearls, the computer- any property they have, once in the black hole- they don’t have anymore.” The physicists’ phrase is “black holes have no hair.” “That means black holes don’t have you-name-it, just-list-it,” says McClintock. “Nothing nothing nothing nothing.”