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01101001
2008-Jul-09, 11:40 PM
Brown University Press Release: Brown-Led Team Finds Evidence of Water in Moon’s Interior (http://news.brown.edu/pressreleases/2008/07/moon08)

BBC: Moon's interior 'did hold water' (http://news.bbc.co.uk/1/hi/sci/tech/7497715.stm)


US scientists have found evidence that water was held in the Moon's interior, challenging some elements of the theory of how Earth's satellite formed.
[...]
But a new study in Nature magazine shows water was delivered to the lunar surface from the interior in volcanic eruptions three billion years ago.

This suggests that water has been a part of the Moon since its early existence.

The discovery came from lunar volcanic glasses, pebble-like beads collected and returned to Earth by the US Apollo missions in the late 1960s and early 1970s.
[...]
"This confirms that water comes from deep within the mantle of the Moon," said lead author Alberto Saal, assistant professor of geological sciences at Brown University.

"It has nothing to do with secondary processes, such as contamination or solar wind."

The researchers believe the water was contained in magma which erupted via "fire fountains" on to the lunar surface more than three billion years ago.

What Max
2008-Jul-10, 02:50 PM
i posted this link earlier in another thread. good that you made a topic here, that way more people will read it and post their opinion. Anyway, there are quite a few other moons in our solar systems which are thought to hold water beneath the surface... so I am not surprised by this discovery.

antoniseb
2008-Jul-10, 02:55 PM
I'm inclined to have doubts about this water thing. Assuming that the samples weren't contaminated by moist Earth air, there is still a very significant chance that since they were found on the surface that might very well be material recently deposited there by a comet impact or a C type asteroid impact, meaning the the water wasn't lunar in origin.

Please note that my doubts don't mean they are wrong and I am right. I'd just like to see something ruling out that possibility before assuming that the Moon was formed with a lot of water in its crust.

01101001
2008-Jul-10, 03:22 PM
i posted this link earlier in another thread.

This article in topic Speed of Theia/Proto-Earth smashup? (http://www.bautforum.com/questions-answers/76217-speed-theia-proto-earth-smashup.html#post1279220)?


interesting article here http://news.bbc.co.uk/2/hi/science/nature/7497715.stm

Yep. You scooped me. In BAUT Forum parlance, I was ToSeeked.

Just, may I suggest a tip for you and other writers? The same things that make a link useful to readers, also make it discoverable. If you had provided some text to describe the linked material, then I might have found it when I did my own search for previous publication: the authors of the paper, the general conclusion, maybe a headline, some key excerpted content. Before posting, I searched for recent articles containing "saal" or "moon" or "water" or "glasses" and didn't get a relevant hit.

So I repeated the news, in a topic of its own. I would have like to have saved my effort by discovering someone had already shared this story.

01101001
2008-Jul-10, 03:36 PM
Assuming that the samples weren't contaminated by moist Earth air, there is still a very significant chance that since they were found on the surface that might very well be material recently deposited there by a comet impact or a C type asteroid impact, meaning the the water wasn't lunar in origin.

I know it's just a few sentences from a press release, and the actual paper might have much more to say about what was ruled out, but did you not find some reassurance in the release (http://news.brown.edu/pressreleases/2008/07/moon08):


The team then confirmed through a series of tests that hydrogen had been present all along, and the samples had not been infused by hydrogen-rich solar winds or tainted by other volatiles.

“This confirms that water comes from deep within the mantle of the Moon,” Saal said. “It has nothing to do with secondary processes, such as contamination or solar wind.”

Kaptain K
2008-Jul-10, 03:53 PM
If the Moon was formed by an impact between the proto-Earth and a Mars sized impactor, it seems obvious to me that, except for the core, the Moon would be almost entirely made of mantle, either Earth or impactor, and would contain at least some water from both!

01101001
2008-Jul-10, 04:28 PM
If the Moon was formed by an impact between the proto-Earth and a Mars sized impactor, it seems obvious to me that, except for the core, the Moon would be almost entirely made of mantle, either Earth or impactor, and would contain at least some water from both!

I think others felt differently about it.

Planetary Society Weblog: Water on the Moon, a big impact on Mars (http://www.planetary.org/blog/article/00001545/)


But it's long been thought that the Moon never had much water, because, the theory goes, the Moon formed when a Mars-sized body slammed into Earth, seding a huge molten mess into orbit that eventually coalesced into the Moon. The process was pretty violent and they thought that pretty much everything volatile went away -- and, under those conditions, elements like sodium and potassium were considered volatile. So how can there still be so much water on the Moon?

It's a stumper.

And, if the numbers are right, it might not be fair to characterize the moon's as just some water:


A few thousand parts per million is a significant fraction of one percent, which may not sound like a big number but it's really a very large number for rock. For comparison, Earth's mantle has only about 150 parts per million; for the whole Earth (including the oceans), it's about 350 parts per million.

NEOWatcher
2008-Jul-10, 04:41 PM
... Before posting, I searched for recent articles containing "saal" or "moon" or "water" or "glasses" and didn't get a relevant hit.
Aha, that's where you went wrong. You should have searched for the word "interesting". :wall:


Oh, BTW, that's sarcasm folks. It means, I agree. I hate blind links. In some cases it gives me the impression that the poster has no clue what's in it other than "I bet the folks at Baut can explain this".



So I repeated the news, in a topic of its own. I would have like to have saved my effort by discovering someone had already shared this story.
IMO:
I consider the search to be the effort. And the post to just be a result of it. In this case I think it stands alone regardless of whether or not it's been ToSeek'd. The only difference is the acknowledgment

timb
2008-Jul-10, 10:45 PM
I think others felt differently about it.

Planetary Society Weblog: Water on the Moon, a big impact on Mars (http://www.planetary.org/blog/article/00001545/)



And, if the numbers are right, it might not be fair to characterize the moon's as just some water:

Brown (http://news.brown.edu/pressreleases/2008/07/moon08) says "up to 46 parts per million" was found. That's a big difference from what is claimed in the blog you cite.

neilzero
2008-Jul-11, 11:58 AM
I think 46 parts per million would be about the minimum water we should expect to find in any body (moon size or larger) in our solar system. Some of the protoplanets = planetoids were likely mostly water. True the surface water was driven back into space in a billion years or less, but some of the water of crystalization should remain unless the interior was heated to 1000 degrees k or hotter for a million years or more. Neil

George
2008-Jul-11, 12:27 PM
If the Moon was formed by an impact between the proto-Earth and a Mars sized impactor, it seems obvious to me that, except for the core, the Moon would be almost entirely made of mantle, either Earth or impactor, and would contain at least some water from both!
I agree with your thinking. 4.5 billion years ago the Sun's accretion disk may have still be quite thick, so the Solar wind might not have been able to drive off the volitales. Indeed, the accretion disk may have greatly contributed to the reason for the impacting of planet, Theia, upon Earth. It is also possible Theia had a higher concentration of water for some reason, as neilzero suggests.

Drunk Vegan
2008-Jul-11, 08:48 PM
This is an exciting month. First Mars, then Mercury, and now the Moon!

I wonder if there is water vapor in Venus' atmosphere. I never would have thought so, but then again I wouldn't have guessed Mercury and the Moon had it either.

Glom
2008-Jul-12, 04:29 PM
The whole galaxy seems to be teeming with water. Where did all this oxygen come from?

Glom
2008-Jul-12, 04:41 PM
I was just reading up more on 'Theia' (cool name btw). Apparently, one of the pieces of supporting evidence for the Giant Impact Hypothesis is that the oxygen isotopic composition of the Moon and Earth are similar indicating they were born of the same original body. I have two questions about this:

1. What are we comparing this too? Do we have isotopic compositions for other bodies that allow us to make the assumption that this property is a genetic identifier? I ask this because I know we have only been able to study Earth and the Moon in any great detail.

2. Why must we assume a Giant Impactor? Can't both Earth and Moon have been born out of the same dust cloud?

01101001
2008-Jul-12, 06:11 PM
[...] the oxygen isotopic composition of the Moon and Earth are similar indicating they were born of the same original body. I have two questions about this:

1. What are we comparing this too? Do we have isotopic compositions for other bodies that allow us to make the assumption that this property is a genetic identifier? I ask this because I know we have only been able to study Earth and the Moon in any great detail.

And meteorites, particularly those interesting ones from Mars and Vesta.

SpaceDaily: Moon and Earth Formed out of Identical Material (http://www.spacedaily.com/reports/Moon_and_Earth_Formed_out_of_Identical_Material.ht ml) (2001, a popular account; plenty of papers will provide the scholarly angle):


The characteristic composition of meteorites from Mars, for example, is different from that of the earth and the moon, or from any other bodies in the solar system. If two big bodies, such as the earth and the moon, have an identical oxygen isotope composition, they formed from an identical mixture of components and were formed at very similar distances to the sun.


2. Why must we assume a Giant Impactor? Can't both Earth and Moon have been born out of the same dust cloud?

Other factors suggest the collision.


The "Giant Impact" theory has been known and accepted by scientists for more than a decade because it provides an explanation for the low density of the moon and the angular momentum of the earth-moon system.

===

Interestingly, that old 2001 article had some problems explaining the different water content of the Earth and Moon:


Uwe Wiechert says: "There are a number of theories on the origin of water. It would be exciting to examine the water recently found on the moon and compare it with earth's water. At present, we presume that the water found on the moon was formed by solar winds, but perhaps here too, we will find the unexpected."

And that brings us around to the recent news of the finding unexpected amounts of water from the Moon's mantle.

toothdust
2008-Jul-17, 02:34 AM
Is there a specific isotopic signature to Earth's bodies of water that could be compared to the moon water?

01101001
2008-Jul-17, 04:14 AM
Is there a specific isotopic signature to Earth's bodies of water that could be compared to the moon water?

Discussed above, the ratio of oxygen isotopes, 16, 17 and 18. There's oxygen in water. It seems not to be a precise single ratio value for a signature, but more a familiar way that oxygen ratios behave in varying from those of a baseline source (the ocean).

I don't know if they've specifically measured the isotope ratios in the tiny quantities of water recovered from the Moon glass. It might be too soon to ask if specific Earth water and Moon water samples have similar isotope ratio behavior -- but I haven't read the article in Nature.

University of Hawaii: Planetary Science Research Discoveries: Oxygen Isotopes (http://www.psrd.hawaii.edu/Dec01/Oisotopes.html):


The mixtures of oxygen isotopes in the Earth, Mars, and the asteroids differ slightly. If we knew why they differ we could learn more about the origin of asteroids and planets and the formation of the solar system. My colleague Sasha Krot and I describe one solution to part of this puzzle. We show how particles in primitive meteorites could have formed from gas and dust close to the Sun. This causes the particles to acquire different mixtures of oxygen isotopes from diverse stars that were ancestors to our own. Planets and asteroids inherited slightly different mixtures of oxygen atoms because they formed from materials like those in primitive meteorites.


The oxygen atoms in rocks that you pick up on Earth do not have identical proportions of 16O, 17O, and 18O atoms but the ratios of these isotopes follow a simple relationship that is controlled by their masses. Rocks with the same 18O / 16O ratio will have the same 17O / 16O ratios. If the 18O / 16O ratio in a given sample is, for example, 0.2% higher than it is in Standard Mean Ocean Water (SMOW), then the 17O / 16O ratio in that sample will depart from SMOW by half as much--in this example, it will be 0.1% higher.

borman
2008-Jul-17, 07:59 PM
I'm inclined to have doubts about this water thing. Assuming that the samples weren't contaminated by moist Earth air, there is still a very significant chance that since they were found on the surface that might very well be material recently deposited there by a comet impact or a C type asteroid impact, meaning the the water wasn't lunar in origin.

Please note that my doubts don't mean they are wrong and I am right. I'd just like to see something ruling out that possibility before assuming that the Moon was formed with a lot of water in its crust.

Perhaps the lack of other expected volitiles that would trace with water with impact melt glasses from comets or asteroids is a clue that these are not involved. After a long cook in the magma, this might allow time to separate the volitiles from the water suggesting it was either from very old impacts or indigenous all along.

While the great impact paradigm may have suffered another setback to go along with the reset problem, one can still appreciate that the impact simulation allowed one to answer some questions within its paradigm regarding the relative content of impactor to Earth ratios allowed that are consistent with the possible angles of impact. The impact scenario may still be valid for some other moons in the solar system.

01101001
2008-Jul-17, 09:35 PM
Sorry I missed this.


Brown (http://news.brown.edu/pressreleases/2008/07/moon08) says "up to 46 parts per million" was found. That's a big difference from what is claimed in the blog you cite.

Maybe the blog (http://www.planetary.org/blog/article/00001545/) writer (Emily Lakdawalla, usually not sloppy) read the Nature article. I didn't. I don't know what the Nature article says. But, this, from the blog, is very likely to be accurate material, signaled by its use of quotation marks:


There's a story in this week's issue of the journal Nature that says that there are parts of the lunar mantle (the part of the interior of the moon that is made of rock, as opposed to the deeper interior, which is made of metal) that contain "a few hundred or even a few thousand parts per million of water."

But there are other specific numbers even in the Brown press release (http://news.brown.edu/pressreleases/2008/07/moon08). It depends on what you wish to compare.

Yes, the actual current water in the glass beads was described as measured at 46 parts per million. Earlier, the same release speaks of other numbers:


Based on their observations that nearly all the water in the lunar magma was lost to space during the eruptions, the researchers calculated that the pre-eruption magma may have contained water up to 750 parts per million [...]

So, even with that quantity, we're back to pretty big numbers -- as compared to current Earth mantle water at 150 ppm.

(Anyone read the Nature article? What numbers are worth comparing, Moon and Earth?)

timb
2008-Jul-19, 11:51 AM
Sorry I missed this.



Maybe the blog (http://www.planetary.org/blog/article/00001545/) writer (Emily Lakdawalla, usually not sloppy) read the Nature article. I didn't. I don't know what the Nature article says. But, this, from the blog, is very likely to be accurate material, signaled by its use of quotation marks:



But there are other specific numbers even in the Brown press release (http://news.brown.edu/pressreleases/2008/07/moon08). It depends on what you wish to compare.

Yes, the actual current water in the glass beads was described as measured at 46 parts per million. Earlier, the same release speaks of other numbers:



So, even with that quantity, we're back to pretty big numbers -- as compared to current Earth mantle water at 150 ppm.

(Anyone read the Nature article? What numbers are worth comparing, Moon and Earth?)

My reading is that there is one number there that is a real measurement of something, 46 parts per million. All the others are, at best, extrapolations. I recommend taking them with a large grain of salt.

Neverfly
2008-Jul-19, 09:31 PM
My reading is that there is one number there that is a real measurement of something, 46 parts per million. All the others are, at best, extrapolations. I recommend taking them with a large grain of salt.

No let's not. Because then we'll have salt water on the Moon and Hoagland will spot something fishy.

Gemini
2008-Jul-20, 01:26 AM
I wonder if there's giant ants in there too. (HG Wells reference).

ryanmercer
2008-Jul-20, 07:45 PM
If the Moon was formed by an impact between the proto-Earth and a Mars sized impactor, it seems obvious to me that, except for the core, the Moon would be almost entirely made of mantle, either Earth or impactor, and would contain at least some water from both!

I agree