Black holes
Wednesday, September 29, 2010 at 7:56PM
Vatche Sahakian in frosh, gravity, relativity

Black holes are the most extreme and violent objects of the universe... They push our understanding of Nature to its limits. A black hole is basically a star that has exhausted all its nuclear fuel and has collapsed under its own weight. If our Sun were to form a black hole (which it won't because it is not heavy enough), all its stuff would collapse into a ball of radius about 3 km (that's around 2 miles) - its current size is 200,000 times more... The surface of a black hole is known as the black hole horizon. If you were falling into a black hole, as you approach its horizon, the rate at which you age will slow down as seen by your worried relatives far away: time gets severly warped near a black hole. You may survive crossing the horizon, but, once you do, you are doomed forever... you will never ever be able to escape - at least not in your preferred form... This is what happens to entire planets and stars when they come too close to a black hole: they get sucked in! A black hole is basically an engine that devours and consumes large amounts of mass as it roams around the universe. It is a drain hole in space that gets larger as it sucks more stuff. In recent years, we have discovered that there are billions of black holes in the universe! more dramatically, some are supermassive: they have devoured billions and billions of stars - that's billion with a 'b'... they typically sit at the center of galaxies as the stars in the galaxy spiral into it - sort of like water flushing down the toilet... Our own galaxy has a supermassive black hole at its center and we are on our way down the drain... I'll write more about this subject in time, specially from the perspective of string theory. For now, check out this amazing video about black holes... a bit long but worth every minute:

Article originally appeared on Physics feed for your imagination (
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