Black holes — regions in space where gravity is so strong that nothing can escape — are a hot topic in the news these days. Half of the 2020 Nobel Prize in Physics was awarded to Roger Penrose for his mathematical work showing that black holes are an inescapable consequence of Einstein’s theory of gravity. Andrea Ghez and Reinhard Genzel shared the other half for showing that a massive black hole sits at the center of our galaxy.
Black holes are scary for three reasons. If you fell into a black hole left over when a star died, you would be shredded. Also, the massive black holes seen at the center of all galaxies have insatiable appetites. And black holes are places where the laws of physics are obliterated.
Black holes are expected to form when a massive star dies. After the star’s nuclear fuel is exhausted, its core collapses to the densest state of matter imaginable, a hundred times denser than an atomic nucleus. That’s so dense that protons, neutrons and electrons are no longer discrete particles. Since black holes are dark, they are found when they orbit a normal star. The properties of the normal star allow astronomers to infer the properties of its dark companion, a black hole.
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The first black hole to be confirmed was Cygnus X-1, the brightest X-ray source in the Cygnus constellation. Since then, about 50 black holes have been discovered in systems where a normal star orbits a black hole. They are the nearest examples of about 10 million that are expected to be scattered through the Milky Way.
Black holes are tombs of matter; nothing can escape them, not even light. The fate of anyone falling into a black hole would be a painful “spaghettification,” an idea popularized by Stephen Hawking in his book “A Brief History of Time.” In spaghettification, the intense gravity of the black hole would pull you apart, separating your bones, muscles, sinews and even molecules. As the poet Dante described the…
Source : cnn
