6 ms·

NASA’s Sofia Discovers Water on Sunlit Surface of Moon

216 points by TangerineDream 6y ago

ginko 6y ago
>We had indications that H2O – the familiar water we know – might be present on the sunlit side of the Moon Doesn't every part of the Moon get some sunlight over the lunar cycle?
- RichWalton 6y ago
  Some parts of some craters are in permanent shadow.
  - cgriswald 6y ago
    This is true, but the phrasing "might be present on the sunlit side of the Moon" is problematic and reinforces the belief (also reinforced by the phrase "dark side") that the Moon has a light and dark side. (At least in the case of 'dark side' an argument could be made that it means 'dark to (historical) human knowledge.' It's hard to defend "sunlit side.")
- dr-detroit 6y ago
  the distinction is they already found molecular water in the parts not lit by sun
- pulkitanand 6y ago
  Tidal forces from Earth have slowed the Moon's rotation to the point where the same side is always facing the Earth—a phenomenon called tidal locking. https://en.wikipedia.org/wiki/Far_side_of_the_Moon https://en.wikipedia.org/wiki/Far_side_of_the_Moon
  - cli 6y ago
    But every side faces the sun at some point. The first paragraph of that article even says so.
tectonic 6y ago
Super cool! Other upcoming missions that are going to be looking for water on the moon: - Lunar IceCube, a 6U CubeSat designed to prospect for lunar water will launch on EM-1, the first Artemis mission. The 14 kg CubeSat will search for water in ice, liquid, and vapor (in the Moon’s very tenuous atmosphere) forms and includes an Iodine-based electric propulsion thruster - Lunar Flashlight CubeSat, another of EM-1’s 13 secondary payloads, will search for ice in permanently shadowed lunar crater regions using an onboard laser. We discussed these missions in Orbital Index a few weeks ago: http://orbitalindex.com/archive/2020-09-30-Issue-84/#lunar-icecube http://orbitalindex.com/archive/2020-09-30-Issue-84/#lunar-i...
brundolf 6y ago
It blows my mind a little bit that spectrosocopy is a thing that just happens to be afforded us by physics, and how much less we'd know about the universe if it didn't exist. "Oh, every element has a totally unique signature and all you need to do is look at it to tell what it is, no matter how many miles or light-years away." It's the kind of thing where if it only existed in a sci-fi novel, it would be considered a far-too-convenient plot point. https://en.wikipedia.org/wiki/Emission_spectrum https://en.wikipedia.org/wiki/Emission_spectrum
- sandworm101 6y ago
  It is an extension of our eyesight. We see objects as being a specific color because they selectively absorb or reflect particular wavelengths of light. Our tri-color vision system can seem some large band gaps and our brain calls that a color. Spectroscopy just sees smaller gaps, smaller absorption lines.
  - brundolf 6y ago
    But all kinds of complicated material-properties can affect the color our eyes see (to my understanding). That alone wouldn't be useful in this way. It's the fact that these signatures exist at an elemental level, and are consistent across all contexts, and can be teased apart at a cosmic scale that makes the technique so powerful.
    - sandworm101 6y ago
      Spectroscopy isn't simple. There are huge grey areas. Very well-defined signatures often overlap into a blurry mess of lines. Even within a single element, say hydrogen, there can be different signatures for different ionization states. Rather than clean detections there is often much opinion and debate, for years, before spectroscopy evidence is agreed as a legitimate detection of a substance.
- jcranmer 6y ago
  It's actually not all that surprising if you approach it from a different angle. Consider that light is nothing more than electromagnetic radiation; it is generated or absorbed only by changes in electromagnetic potential. Now also consider that electron orbitals in molecules are discrete and quantized: you can be in this orbital (with such-and-such potential energy) or in that orbital (with a slightly different potential energy) but you cannot exist between those two orbitals. Therefore, light can only be absorbed or emitted by a molecule if it can precisely force an electron into a different orbital, which in classical terms means that it only works if light has a particular frequency. As you might imagine, sticking protons (which generate electron fields) at different positions within a molecule, or equivalently adding protons to an atomic nucleus, will change the permissible orbitals very slightly. Consequently, the light that an atom or molecule can emit or absorb will change as well.
moonbug 6y ago
Context: NASA keen to show SOFIA's worth https://www.nature.com/articles/d41586-020-00685-2 https://www.nature.com/articles/d41586-020-00685-2
- part1of2 6y ago
  > SOFIA’s publication rate is now starting to creep up, and last year it was 33 papers. The ultimate goal is 75 to 100 papers per year, says James Jackson, associate director for research at the Universities Space Research Association, the Maryland-based group that manages SOFIA. “More than 150 was a stretch goal,” he says. I don't think a number is the right target here. Discoveries or theories might be a better goal, not just the number of papers published
- tonywastaken 6y ago
  > The coronavirus pandemic is likely to keep it grounded for some time and threatens a planned deployment to New Zealand later this year. How long can this modified 747SP fly? I wonder how they were going to fly it to New Zealand and if there were any refuel stops. Would be a nice treat to catch that at your local airport.
1024core 6y ago
If comets are icy things, and are constantly crashing into the Earth and the Moon, why shouldn't we expect water on the moon?
- vladTheInhaler 6y ago
  I think it's not so much the presence as it is the amount. Given the moon's lack of atmosphere, low gravity, and exposure to solar wind, you might expect the water to quickly boil off into space. But apparently it sticks around for quite a while.
- marcosdumay 6y ago
  Because the Moon doesn't have an atmosphere, so any water that gets slightly hot vaporizes and goes away into space. So, at least near the surface and on areas where the Sun light reaches, it's not obvious at all that we would find any water.
  - ric2b 6y ago
    Shouldn't the moon's gravity keep it there?
neverknew200 6y ago
Does this mean that there could be life on the moon?
part1of2 6y ago
> concentrations of 100 to 412 parts per million – roughly equivalent to a 12-ounce bottle of water – trapped in a cubic meter of soil spread across the lunar surface This is incredible. Is there speculation that there could be a resevoir of ice underneath the soil? As in, could they dig a well and attempt to melt it (somehow) for collection?
- bombela 6y ago
  12 fluid ounce: ~355ml (excerpt likely meant fluid ounce). 12 ounce: ~340g
- valuearb 6y ago
  Pure ice would require a 2,500 times increase in water proportions. That’s a big increase. It does seem reasonable that sub soil not heated to 260 degrees every two weeks for two weeks at a time would contain a lot more water. But when Lunar Prospector was crashed into Crater Shoemaker, the plume was mostly soil never exposed to sunlight and water density was minuscule.
ThomasMidgley 6y ago
Wrong. Better: "NASA/DLRs Sofia Discovers Water on Sunlit Surface of Moon" Telescope and some of the instruments are powered by German engineering! https://en.wikipedia.org/wiki/Stratospheric_Observatory_for_Infrared_Astronomy https://en.wikipedia.org/wiki/Stratospheric_Observatory_for_... Greetings from Germany ;-)
- sebmellen 6y ago
  Ist es nicht der Fall, dass fast alle moderne sachen irgend einen ursprung in Deutsche technik haben?
supernova87a 6y ago
Maybe I'm airing some bit of dirty astro laundry here, but on my last looking at SOFIA (a decade ago?), it was not a very cost-efficient or preferred option compared to just sending a NASA SMEX (satellite) mission up with similar instruments? Is that still the case? I.e. for the amount you spend flying the plane around, and the increase in collecting area needed compared to going all the way to space (much smaller mirror if you just go to space), we could've gotten more by sending a 30cm satellite into orbit. Is that right? Or am I out of date?

>We had indications that H2O – the familiar water we know – might be present on the sunlit side of the Moon Doesn't every part of the Moon get some sunlight over the lunar cycle?

RichWalton 6y ago
Some parts of some craters are in permanent shadow.
- cgriswald 6y ago
  This is true, but the phrasing "might be present on the sunlit side of the Moon" is problematic and reinforces the belief (also reinforced by the phrase "dark side") that the Moon has a light and dark side. (At least in the case of 'dark side' an argument could be made that it means 'dark to (historical) human knowledge.' It's hard to defend "sunlit side.")
dr-detroit 6y ago
the distinction is they already found molecular water in the parts not lit by sun
pulkitanand 6y ago
Tidal forces from Earth have slowed the Moon's rotation to the point where the same side is always facing the Earth—a phenomenon called tidal locking. https://en.wikipedia.org/wiki/Far_side_of_the_Moon https://en.wikipedia.org/wiki/Far_side_of_the_Moon
- cli 6y ago
  But every side faces the sun at some point. The first paragraph of that article even says so.

tectonic 6y ago

Super cool! Other upcoming missions that are going to be looking for water on the moon: - Lunar IceCube, a 6U CubeSat designed to prospect for lunar water will launch on EM-1, the first Artemis mission. The 14 kg CubeSat will search for water in ice, liquid, and vapor (in the Moon’s very tenuous atmosphere) forms and includes an Iodine-based electric propulsion thruster - Lunar Flashlight CubeSat, another of EM-1’s 13 secondary payloads, will search for ice in permanently shadowed lunar crater regions using an onboard laser. We discussed these missions in Orbital Index a few weeks ago: http://orbitalindex.com/archive/2020-09-30-Issue-84/#lunar-icecube http://orbitalindex.com/archive/2020-09-30-Issue-84/#lunar-i...

brundolf 6y ago

It blows my mind a little bit that spectrosocopy is a thing that just happens to be afforded us by physics, and how much less we'd know about the universe if it didn't exist. "Oh, every element has a totally unique signature and all you need to do is look at it to tell what it is, no matter how many miles or light-years away." It's the kind of thing where if it only existed in a sci-fi novel, it would be considered a far-too-convenient plot point. https://en.wikipedia.org/wiki/Emission_spectrum https://en.wikipedia.org/wiki/Emission_spectrum

sandworm101 6y ago
It is an extension of our eyesight. We see objects as being a specific color because they selectively absorb or reflect particular wavelengths of light. Our tri-color vision system can seem some large band gaps and our brain calls that a color. Spectroscopy just sees smaller gaps, smaller absorption lines.
- brundolf 6y ago
  But all kinds of complicated material-properties can affect the color our eyes see (to my understanding). That alone wouldn't be useful in this way. It's the fact that these signatures exist at an elemental level, and are consistent across all contexts, and can be teased apart at a cosmic scale that makes the technique so powerful.
  - sandworm101 6y ago
    Spectroscopy isn't simple. There are huge grey areas. Very well-defined signatures often overlap into a blurry mess of lines. Even within a single element, say hydrogen, there can be different signatures for different ionization states. Rather than clean detections there is often much opinion and debate, for years, before spectroscopy evidence is agreed as a legitimate detection of a substance.
jcranmer 6y ago
It's actually not all that surprising if you approach it from a different angle. Consider that light is nothing more than electromagnetic radiation; it is generated or absorbed only by changes in electromagnetic potential. Now also consider that electron orbitals in molecules are discrete and quantized: you can be in this orbital (with such-and-such potential energy) or in that orbital (with a slightly different potential energy) but you cannot exist between those two orbitals. Therefore, light can only be absorbed or emitted by a molecule if it can precisely force an electron into a different orbital, which in classical terms means that it only works if light has a particular frequency. As you might imagine, sticking protons (which generate electron fields) at different positions within a molecule, or equivalently adding protons to an atomic nucleus, will change the permissible orbitals very slightly. Consequently, the light that an atom or molecule can emit or absorb will change as well.

moonbug 6y ago

Context: NASA keen to show SOFIA's worth https://www.nature.com/articles/d41586-020-00685-2 https://www.nature.com/articles/d41586-020-00685-2

part1of2 6y ago
> SOFIA’s publication rate is now starting to creep up, and last year it was 33 papers. The ultimate goal is 75 to 100 papers per year, says James Jackson, associate director for research at the Universities Space Research Association, the Maryland-based group that manages SOFIA. “More than 150 was a stretch goal,” he says. I don't think a number is the right target here. Discoveries or theories might be a better goal, not just the number of papers published
tonywastaken 6y ago
> The coronavirus pandemic is likely to keep it grounded for some time and threatens a planned deployment to New Zealand later this year. How long can this modified 747SP fly? I wonder how they were going to fly it to New Zealand and if there were any refuel stops. Would be a nice treat to catch that at your local airport.

1024core 6y ago

If comets are icy things, and are constantly crashing into the Earth and the Moon, why shouldn't we expect water on the moon?

vladTheInhaler 6y ago
I think it's not so much the presence as it is the amount. Given the moon's lack of atmosphere, low gravity, and exposure to solar wind, you might expect the water to quickly boil off into space. But apparently it sticks around for quite a while.
marcosdumay 6y ago
Because the Moon doesn't have an atmosphere, so any water that gets slightly hot vaporizes and goes away into space. So, at least near the surface and on areas where the Sun light reaches, it's not obvious at all that we would find any water.
- ric2b 6y ago
  Shouldn't the moon's gravity keep it there?

neverknew200 6y ago

Does this mean that there could be life on the moon?

part1of2 6y ago

> concentrations of 100 to 412 parts per million – roughly equivalent to a 12-ounce bottle of water – trapped in a cubic meter of soil spread across the lunar surface This is incredible. Is there speculation that there could be a resevoir of ice underneath the soil? As in, could they dig a well and attempt to melt it (somehow) for collection?

bombela 6y ago
12 fluid ounce: ~355ml (excerpt likely meant fluid ounce). 12 ounce: ~340g
valuearb 6y ago
Pure ice would require a 2,500 times increase in water proportions. That’s a big increase. It does seem reasonable that sub soil not heated to 260 degrees every two weeks for two weeks at a time would contain a lot more water. But when Lunar Prospector was crashed into Crater Shoemaker, the plume was mostly soil never exposed to sunlight and water density was minuscule.

ThomasMidgley 6y ago

Wrong. Better: "NASA/DLRs Sofia Discovers Water on Sunlit Surface of Moon" Telescope and some of the instruments are powered by German engineering! https://en.wikipedia.org/wiki/Stratospheric_Observatory_for_Infrared_Astronomy https://en.wikipedia.org/wiki/Stratospheric_Observatory_for_... Greetings from Germany ;-)

sebmellen 6y ago
Ist es nicht der Fall, dass fast alle moderne sachen irgend einen ursprung in Deutsche technik haben?

supernova87a 6y ago

Maybe I'm airing some bit of dirty astro laundry here, but on my last looking at SOFIA (a decade ago?), it was not a very cost-efficient or preferred option compared to just sending a NASA SMEX (satellite) mission up with similar instruments? Is that still the case? I.e. for the amount you spend flying the plane around, and the increase in collecting area needed compared to going all the way to space (much smaller mirror if you just go to space), we could've gotten more by sending a 30cm satellite into orbit. Is that right? Or am I out of date?