Early Blast

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The explosive death of a star played a role in the birth of our solar system, but it may not be the role that astronomers had expected.

For a long time, the idea has been that the Sun and planets were born as the result of an exploding star, called a supernova. The shockwave from the blast squeezed a big cloud of gas and dust, causing it to collapse and form the Sun and its planets.

But there's evidence that the blast came shortly after the Sun was born, not before.

Researchers have studied meteorites that date back to the very early solar system. Those that are a little younger -- a million years or so -- have larger amounts of elements that formed as the result of a supernova.

So a new scenario is emerging.

In this view, the Sun was born in a cluster of stars -- perhaps thousands of them, of all sizes. The energy from the hotter, heavier stars in the cluster helped squeeze the surrounding blobs of gas, triggering the birth of still more stars. But these stars also whittled away the blobs, so that they gave birth to smaller stars, like the Sun.

Perhaps a million years after the Sun started shining, a supernova exploded just a few light-years away. The Sun and its surrounding disk of gas and dust were buffeted by the blast, but not harmed. But solid grains of nickel and other elements peppered the solar system like a cosmic hailstorm. Many of these grains were incorporated into the newly forming planets -- including Earth.

Script by Damond Benningfield, Copyright 2008

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