Comet's water 'like that of Earth's oceans'

BBC ^ | October 5, 2011 | Jason Palmer

[decimon]

Comet Hartley 2 contains water more like that found on Earth than prior comets seem to have, researchers say.

A study using the Herschel space telescope aimed to measure the quantity of deuterium, a rare type of hydrogen, present in the comet's water.

The comet had just half the amount of deuterium seen in comets.

The result, published in Nature, hints at the idea that much of the Earth's water could have initially came from cometary impacts.

Just a few million years after its formation, the early Earth was rocky and dry; something must have brought the water that covers most of the planet today.

Water has something of a molecular fingerprint in the amount of deuterium it contains, and only about a half-dozen comets have been measured in this way.

All of them have exhibited a deuterium fraction twice as high as the oceans, so the current theory holds that asteroids were likely to be the carriers for water; meteorites that they give rise to have roughly the same proportion of deuterium that the Earth's oceans contain.

[Grimmy]

And here I was thinking that the oceans were formed by early man drinking too much beer.

[decimon]

How much water is in a comet compared to that in the earth’s oceans? Is it plausible that a strike on the earth by a large dry rock could cause ocean water to splash out into outer space, in such a way that it would enter a highly elliptical orbit about the sun and become a comet?

One of the links in the comments above has something about a whole lot of comets over a long time period.

[ari-freedom]

There’s much to my comment that I’m not letting on :)

[dfwgator]

Comet - it will make your teeth turn green
Comet - it tastes like gasoline

Comet- it will make you vomit
So get some Comet, and vomit, today

[1010RD]

Fascinating stuff, but it still doesn’t solve the origin of life issue.

[1010RD]

Twenty per minute, IIRC. But, they’d have to be big enough to get through the atmosphere with their water intact and insufficient volume, unless there wasn’t any atmosphere back then.

That rate is nearly 29000 per day and over 10 million in the course of a year. How many gallons of water are there on earth?

[Ken H]

One reindeer did all that?

[blam]

"And who says conservatives don’t do science. LOL "

Thanks. I just had the best laugh of the day.

[HiTech RedNeck]

What’s this per minute stuff? Talking about a single comet.

[aruanan]

Lou Frank has been attacked for twenty years on this subject.

I thought it was hilarious how the radar data of small meteorites, the 1980s small comet satellite data, and the 1990s small comet satellite data all give exactly the same graph. And that astronomer who developed the skeet shoot method of getting an exposure on these objects was great. Too bad he died so soon. I think it was diabetes.

Something everyone who accepts the reality of stones falling from space but not water should remember is what the scientists were saying about folks who claimed that stones were falling to the ground from space back in the 18th century:

The German physicist, Ernst Florens Chladni, was the first to publish the then audacious idea that that meteorites were actually rocks from space.[35] He published his booklet, "On the Origin of the Pallas Iron and Others Similar to it, and on Some Associated Natural Phenomena", in 1794. In this he compiled all available data on several meteorite finds and falls concluded that they must have their origins in outer space. The scientific community of the time responded with resistance and mockery.[36] It took nearly 10 years before a general acceptance of the origin of meteorites was achieved through the work of the French scientist Jean-Baptiste Biot and the British chemist, Edward Howard. Biot's study, initiated by the French Academy of Sciences, was compelled by a meteorite fall of thousands of meteorites on April 26, 1803 from the skies of L'Aigle, France.[37][38]

I have a feeling that this "community" is a lot more resistant now to new ideas than it was then. Of course, that very public fall of thousands of meteorites in France helped a lot. Too bad we couldn't luck out on this one with something like that over, say, Washington, D.C..

[SunkenCiv]

Right after it ran over grandma.

[Condor51]

The result, published in Nature, hints at the idea that much of the Earth's water could have initially came from cometary impacts.

I haven't pulled out my slide rule, but I have a *problem* with that theory.

To wit: If you calculated, or estimated, the volume of all the water in the earth's oceans (not even all the lakes and rivers), then factored in the size of the 'average' comet head containing ice you would need a 'googol' of Comets hitting the earth during its 'formative' years - after it cooled but had no water.

Then after 'a while' (scientific term) some of that water would have formed a young atmosphere creating friction for the latter comets with water ice hitting the earth, which would evaporate the water into a gas. And that friction factor would then increase exponentially ('e') as our atmosphere increased. And keep in mind the comet(s) couldn't be too large or the debris field expelled 'up' would create an added friction factor for the other comets to pass through.

Granted, the young solar system was a violent place, just look at the moon. But comets being the source of all our water? I can't imagine the number ('n') of comets involved which would result in getting a '+' = 'water'.

Think I'll fire off an email to Stephan Hawking today for his take on this.

[SunkenCiv]

Since the water burned off in descent would not escape back into space, it would wind up in the oceans.

It’s amusing to contemplate how much rain results from this.

[SunkenCiv]

In a word, no.

[SunkenCiv]

Thanks aruanan. The “stones don’t fall from the sky” idiocy comes straight down from Aristotle. He also originated the ridicule of people who said that they did.

[SunkenCiv]

The atmosphere absorbed any water that melted off the comets, which is what is being observed now. Just having an atmosphere doesn’t result in the melt being able to achieve escape velocity.

[redgolum]

My thought also.

[1010RD]

One of the links provided by a poster leads to a postulation by two scientists who made observations on the meteorites. Their theory is what I am referring to.

[1010RD]

So atmosphere or no the water gets here. Does it matter at what height in the atmosphere the water is deposited? That is could it have formed static ice crystals in space after burning off the meteor?

[colorado tanker]

We can't let the Nazis get the heavy water. The ancient aliens said they would come back for it.">