SSS 2011-07-05

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If you’ve ever wondered where the Earth came from, the answer, it seems, is blowin’ in the wind—the solar wind. Or so say scientists who, after examining solar wind samples collected by the Genesis spacecraft, conclude that the inner planets of our solar system formed a little differently than we’d thought. The work appears in the journal Science. 

 

Our solar system arose from a large, rotating cloud of interstellar debris¹ called the solar nebula². The sun came first and the planets followed not long after.

 

But the new study shows that the ratio of oxygen and nitrogen isotopes⁴ found in the solar wind is different from the ratio here on earth, or on the moon or Mars. We’ve got more of the heavier versions of these atoms than our Sun does.

 

Now we just have to figure out why. Scientists say the excess heavy nitrogen could have come from a comet. And the heavier oxygen from a natural process that left more of the light isotope³ in the part of the nebula that made the sun. So we are made of star stuff. But when it comes to our elemental composition, we’re not a carbon copy.

 

Thanks for the minute. For Scientific American’s 60-Second Science, I’m Karen Hopkin.

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