Posted on 11/08/2009 8:25:37 PM PST by MikeD
It would be fair to say that the crashy culmination of NASA's LCROSS mission on October 9th was a technical success but a public-relations fizzle.
LCROSS on final approach LCROSS and its Centaur rocket prepare to crash into the Moon. NASA On the plus side, the engineering team for LCROSS (short for Lunar Crater Observation and Sensing Satellite) delivered as promised, deftly driving a spent 2½-ton Centaur rocket into a target zone near the Moon's south pole only 2 miles (3½ km) across. Four minutes later, after flying through the debris cloud raised by the rocket's crash, an instrument-packed 600-kg "shepherding spacecraft" augered in not far away.
But the team's hope of finding abundant water buried in the permanently shadowed floor of Cabeus, the 61-mile-wide target crater, has yet to pan out. Water molecules have strong spectral signatures in the near-infrared, and even one part water ice in 200 parts lunar dust should have been easy to spot.
(Excerpt) Read more at skyandtelescope.com ...
No water and mercury toxicity in both dust and air, that’s going to cause a dust up.
Interesting. Thanks for posting.
Very interesting. Thanks for posting it.
the article says the lunar pole region is one of the most frigid places known in the entire solar system, and not much warmer than absolute zero, how could that be ?
No volcanic activity and no atmosphere.
1) Proved that the alien lunar bases use mercury and no water by smashing one into powder.
2) We now owe the pissed-off aliens an apology AND a lunar base that is high in mercury and contains no water.
Nice job guys.
seems that asteroids and other moons further from the sun would be much colder than the moon which is relatively close to the sun in comparison?
This NASA site says the surface of Triton ( a moon of Neptune ) is 38K, and this is colder than Pluto because of its low albedo. It doesn't have sheltered poles the way the moon does because of the extreme tilt of its orbit. However, one of its poles would point away from the sun for about 80 years at a time, and since its rotation is synchronous with its orbit, the poles should be oblique to Neptune itself, and I myself don't see why the "spaceward" pole wouldn't get colder than the average surface.
The wikipedia article on Triton has a lot of interesting related facts, but I don't see the question of temperature variation on the surface directly addressed. It says, "Little is known about the north pole because it was on the night side during the Voyager 2 encounter." ... and still is, I guess, although it has been 20 years.
I guess the key word is "known," because no temperature colder than 37K has been measured there.
It's just these few spots on the moon. The unique properties are the stable orientation of the moon, the lack of volatiles, and hence atmosphere ( as omega4179 points out, ) and the deep craters. Triton is flat because the icy surface cannot sustain vertical relief.
It certainly is a surprising assertion, but solar radiation in space is directional, and if you are effectively shielded from it you will obtain deep cold by radiating directly into space.
This means the shadowed floors within Cabeus and its neighbors are the most frigid places known in the entire solar system
I get really torqued... Any scientist who makes such an absolute, sweeping and, yes, ignorant statement like that makes anything else they say totally suspect.
When he has measured absolutely every square millimeter in the solar system, and documented it all, then he may be able to make such a statement with authority. But would any serious scientist make such a sweeping - and possibly easily disproven -statement? I've read a few other similar sweeping absolutes supposedly made by scientists and they just grate on my nerves when I see them in print.
Yes I'm aware that it says "known in the solar system", but there is a LOT of "known" solar system that hasn't been measured, temperature-wise. I'm also aware that "may, might, could and possibly" can often be used as weasel words, but in this case wouldn't "are possibly the most frigid" be a little more "scientific"?
[singing] see what’s inside of you...
On an astronomical scale, it is much warmer than absolute zero (~40 Kelvin or so). The craters at the lunar poles never see sunlight, so they have no direct heat source. They radiate their intrinsic heat to deep space, which is about 4 Kelvin. There is a small amount of conductive heating through the lunar soil, but it is only enough to maintain the 40 Kelvin or so temperature.
It says, "most frigid places known in the entire solar system," not "most frigid places in the entire known solar system."
Anyway, here is the language from the NASA science page ( note garbled editing ) : "Diviner has recorded minimum daytime brightness temperatures in portions of these craters of less than 35K (-397° F) in the coldest areas. These are to our knowledge, these super-cold brightness temperatures are among the lowest that have been measured anywhere in the solar system, including the surface of Pluto."
... so it is more tentative than the cited article. Check out the infrared images, though. These are quite remarkable. The darker areas in figure 5 are the supercold spots at the south pole:
I guess that "These are to our knowledge, these super-cold brightness temperatures (sic) are among the lowest that have been measured anywhere in the solar system, including the surface of Pluto" as written on the NASA page, when run through the 'semi-literate journalism' filter becomes "This means the shadowed floors within Cabeus and its neighbors are the most frigid places known in the entire solar system (emphasis in original). To my mind, there is a pretty vast difference between the two statements-- and just seems to indicate the writer's incompetence, or at least his desire for sensationalism.
But, anyway...
Another thing that struck me when I was trying to visualize the earth/moon/sun spatial relationship was this: Although we only see one side of the moon because it is tidal locked to our planet, doesn't the 'dark side' face the sun during its rotation around the planet as the planet rotates around the sun? So isn't the 'dark side' of the moon just 'dark' to us- or rather 'unseen' by us, while being illuminated by the sun when it is between earth and the sun?
I guess I will have to go find a good online representation of an orrery, as my spatial visualization seems to be severly lacking in that respect.
Then, after straining what few brain cells I do have left on that, another question arose: Why, when the moon is only 1 AU from the sun are places on it colder than places that are multiple or many AU's away from the sun. Doesn't the radiation fall off with the square of the distance, like light, thus subjecting distant objects to even less warming than what could be gotten closer to the solar furnace, i.e., the moon? I guess it's been too many years since those old college science courses.
Anyway, thanks for that picture. It is amazing. Am I correct in assuming that it was one of the ones taken during the suicide plunge of the LCROSS, since it seems so high rez and detailed?
Yes, but we are talking about the lunar poles, not the "dark side". Interestingly, the lunar axis of rotation is inclined by only 1.54 degrees to the plane of the earth's ( or earth-moon ) orbit around the sun, although it is inclined at 6.69 degrees to its orbit around the earth. The latter inclination gives it a "nodding" appearance from the earth, but the smaller inclination to its ( shared ) orbit around the sun means that the sun is never more than 1.54 degrees above or below the horizon at the poles, and the local topography at the south pole creates these deep shadow zones.
BTW, I was just experimenting with my STARRY NIGHT software, which lets me hover over the lunar south pole and watch the sky turn ( set to X30000 ) as the earth spins in front of me. Great stuff.
Why, when the moon is only 1 AU from the sun are places on it colder than places that are multiple or many AU's away from the sun.
We've been trying to tell you! But I think you're coming around. The moon's solidity and lack of atmosphere provides a shield against the solar radiation, and allows the deep cooling due to constant darkness without thermal contact to any gases. You might think that the rock itself would warm the place up through conduction, but the great thickness of it prevents this. You have to do the math, really, and in fact I don't think the experts were expecting anything very much below 100K
Am I correct in assuming that it was one of the ones taken during the suicide plunge of the LCROSS, since it seems so high rez and detailed?
That is NOT correct, sir! The image is from the Diviner Lunar Radiometer Experiment aboard the Lunar Reconnaissance Orbiter, launched last June.
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