Summary: The universe is filled with life-and-death struggles. Comets pass too close to their stars and are vaporized. Dying stars shatter nearby planets. And black holes gobble up anything that passes within their sphere of influence — accompanied by spectacular displays of fireworks. An example of that was discovered just last year. Orbiting X-ray telescopes detected bright pulses of energy from a galaxy that’s almost four billion light-years away. At first, astronomers thought the outburst was a powerful explosion known as a gamma-ray burst. But it didn’t fade out in the same way as gamma-ray bursts normally do. Instead, the space telescopes saw pulses of X-rays lasting about three-and-a-half minutes. Analysis showed that the most likely explanation was the death of a star that was passing close to a black hole. As the star approached the black hole, it was ripped apart by the black hole’s increasingly powerful gravitational pull. As it spiraled into the black hole, the star’s gas formed a superhot disk that produced a lot of X-rays. As the gas in the innermost part of the disk whipped around the black hole, it produced the pulses of X-rays. And some of the gas was funneled into “jets” that squirted away from the black hole’s poles. The pulses of energy didn’t last long, though. They faded away in weeks, as material in the disk poured into the black hole — and the star lost its life-and-death struggle. More about black holes tomorrow. Script by Damond Benningfield, Copyright 2012 For more skywatching tips, astronomy news, and much more, read StarDate magazine.
