Is Earth's Atmosphere an Import?

garg0yle writes "One of the questions about the formation of our planet is: where did the atmosphere come from? One theory is that the oxygen, nitrogen, and other gases were part of the coalescing ball, and 'seeped out' during the final stages of the planet's formation. However, a new article at Wired says isotopic analysis of krypton and xenon indicates that they (and the rest of our atmosphere) may be of extraterrestrial origin, either arriving via comets or being swept up from gas clouds."

Comments

Wha...?

[Anonymous Coward]

It's hard to understand how you can extrapolate a whole atmosphere's origins by looking at a couple of very rare gases like krypton and xenon.

Given that all the elements that make up the Earth were manufactured in the same solar furnace(s) why is it necessary that some originated separately from others? How do you then explain the huge atmospheres of the Gas Giants? It would take an unlikely number of very large asteroids to do the job.

This hypothesis suffers from the same shortcomings as the Transpermia idea. It just moves the problem elsewhere, at best.

Re:Science?

[MightyMartian]

None of the planets you list have the proportionally large amounts of O2 that Earth does. It's not that Earth has a large atmosphere, it's that the atmosphere is in so many ways different from even the other Earth-like bodies (hint Venus and Mars' atmospheres are dominated by CO2). The gas giants are a totally different creature; they are largely made up of hydrogen.