Here on Earth, Nature recycles rocks, dead plants and animals, and just about everything else. But out in the universe, it may recycle entire planets.
An example is a system known as PSR 1257+12 -- the first confirmed planets discovered outside our own solar system. The system contains three planets that are roughly comparable to Earth -- fairly small, and probably made of rock. But their history and environments are anything but Earthlike.
The planets orbit the corpse of a once-mighty star. The original star was a supergiant -- much bigger, heavier, and hotter than the Sun. It lived a short but dazzling life, then blasted itself to bits as a supernova.
The star's core collapsed to form a neutron star -- an object that's several times as massive as the Sun, but no bigger than a city. It's so tiny that you couldn't even see it from its planets.
When the star exploded, any distant planets might have been hurled away at breakneck speeds. But planets at close range would have been pulverized. So the planets in the system today weren't always there. They probably formed from the debris left over from the blast -- a case of recycling on a gigantic scale.
The system is in Virgo, which scoots across the southwestern sky tonight. Look for the constellation's brightest star, Spica. PSR 1257 is too faint to see, but it's not far from Spica -- a system of planets rebuilt from the ashes of a mighty blast.
Script by Damond Benningfield, Copyright 2008
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