comets

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Can you guys point me in the right direction on how to figure this out.

 

How many comets would have to strike the Earth in order to account for the roughly 2x10^21 kg of water presently found on our planet?

[antimatter]

2x10^21 you mean?

[ads8525]

yes

[Realitycheck]

a lot

 

The range is anywhere from a few hundred meters to tens of kilometers in diameter.

[iNow]

I'm confused by the question.

 

What do comets have to do with the water on Earth? Are you suggesting that all [ce]H2O[/ce] on our planet is a result of cometary action?

 

If so, that seems to ignore a pretty significant amount of, what can only be described as, basic chemistry.

[Realitycheck]

How feasible is it that hydrogen would react with oxygen in a primordial state to produce water? My guess is that it would have to be pressurized.

[iNow]

Pressurized is a relative term.

 

http://www.newton.dep.anl.gov/askasci/chem03/chem03212.htm

[D H]

I'm confused by the question.

 

What do comets have to do with the water on Earth? Are you suggesting that all [ce]H2O[/ce] on our planet is a result of cometary action?

 

If so, that seems to ignore a pretty significant amount of, what can only be described as, basic chemistry.

Cometary impact remains the dominant hypothesis regarding the origin of water on the Earth. The basis for the hypothesis is that the water has to come from somewhere after all. The water could have arisen either through accretion during the initial formation of the Earth or have been added to the Earth later on via some other mechanism. Most astronomers think accretion is not the answer, as the very early Earth was far too hot. If not accretion, then comets are the next obvious answer. The early solar system had a lot of comet-like objects.

 

The cometary origin hypothesis is just that -- a hypothesis, and some astronomers are beginning to question it.

[Realitycheck]

I'm thinking of a hydrogen fuel cell engine. It requires hydrogen and oxygen, pressure, and emits water. Would the congregation of gases in planetary formation be of sufficient pressure in order to allow this reaction? I mean, if we can get nuclear fusion to happen, it seems like it would be a lot easier to get this reaction going. Does it really matter if the water is created as steam? Hydrogen engines do produce heat as well and do not work well in cold conditions.

[iNow]

I appreciate the info, DH.

 

I am not inclined to accept that all of the water on our planet was "pansperm-ied," but I'll concede that some water may have arrived via this route.

[Jacques]

The main accepted view is that earth water comes from comets impact, because of the hydrogen and deuterium ratio is the same as the comets, but some have other explaination

"pansperm-ied,"

This word applies to life seeding material comming from space.

How feasible is it that hydrogen would react with oxygen in a primordial state to produce water?

Just need a mixture of H and O and a spark.