Comets Probably Seeded Earth's Nitrogen Atmosphere

KentuckyFC writes "One of the biggest puzzles of astrobiology is the origin of the Earth's oceans and atmosphere. One favored theory is that our water is the leftovers from a bombardment of comets early in Earth's history. But the ratio of hydrogen and deuterium in the oceans doesn't match the ratio in the four comets measured so far (Halley's, Hyakutake, Hale-Bopp and C/2002 T7 LINEAR). Now a new analysis of the ratio of nitrogen-14 and 15 isotopes in these comets and on Earth places new limits on how much of our environment could have come from comets. On the one hand, the astronomers who did the work say that no more than a few percent of Earth's water could have come from comets. But on the other, they say that the ratio of nitrogen isotopes in these comets almost exactly matches the ratio in Earth's atmosphere. That suggests that while Earth's oceans must have come from somewhere else, Earth's early atmosphere was probably seeded by comets."

Comments

It is possible, but not certain

[comet63]

The article notes that the ratio of the nitrogen isotopes matches what is in the earths atmosphere. It seems to me, that just makes it possible that the comets are a significant source of the nitrogen on Earth. It is also possible that the nitrogen in the comets and in the atmosphere came from a common source.

Re:Determining the origins of ....

[alexhard]

>method of guessing based on simply "interesting patterns"

That would be the SCIENTIFIC method (or at least the first part of it), the source of all scientific advancement since whenever.

Re:That seems to make some sense.

[TheTurtlesMoves]

By your reasoning only economist should comment on topics of economy, climatologists on topics of global warming, etc...

This is /. you are allowed to speculate and the reader shouldn't be such an idiot to assume every post is by an expert or a lawyer (IANAL crap).

Even more important experts can and should be questioned. People outside the field can give suggestions and should criticize experts if they cannot justify their point of view. The only times we get a group of people that think they cannot be questioned by outsiders... they are usually wrong.

And what are your credentials? Modding expert? Modding consultant?

By the way I am an astronomer by training... Grandparent has a good point.