The year 1987 saw the first supernova explosion since 1604 that was visible to the eye, though only in the Southern Hemisphere. Designated Supernova 1987A, this stellar catastrophe occurred some 169,000 years ago in the Large Magellan Cloud, a "dwarf galaxy" that it the closest interstellar structure to our own galaxy, the Milky Way. Light from the explosion has been traveling toward Earth ever since.

This image shows a set of eerie rings of glowing gas that emanate from the point where the unnamed star detonated. Many of the world's telescopes periodically check this region of space, since some astronomers believe that a black hole and a remnant star are about to collide within these rings. Or to be precise, that these objects collided long ago, but the evidence is about to reach the earth.

Supernovas are subjects of fascination not just for their power but for their role in the evolution of the cosmos. Most Big Bang theories hold that the early universe contained only the light elements hydrogen, helium, and lithium--none of the carbon necessary for organic life, nor the heavy subtonics necessary to form planets. It's also believed that the early universe contained a profusion of exceptionally hot stars that burned up their nuclear materials relatively fast, then exploded into supernovas. As stars burn, they convert hydrogen and helium into carbon and then the heavy elements. When they explode, they cast these elements out into space.

Most cosmologists believe that in the first era of the universe, huge numbers of violent, super-hot, unstable stars essentially manufactured the heavy elements, then blew up, scattering their materials into swirling nebulas. In the second era of the cosmos, stable and slower-burning stars like our sun began to coalesce from the debris of the first generation of stars. Around these new stable stars formed the first planets, made of the heavy elements drifting in space from the supernova explosions.

That is the ground on which you are standing, to say nothing of the elements in your own body, was originally forged from ancient exploding stars. Another haunting thought: that because the heavy elements have only "recently" become available, the existence of planets is a relatively "recent" event in cosmic terms, and thus only now is the universe beginning to be able to host life.

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