5 ms·

For a more technical description, the paper is here: http://onlinelibrary.wiley.com/doi/10.1002/2017GL074998/full http://onlinelibrary.wiley.com/doi/10.1002/201

by yosyp 9y ago

For a more technical description, the paper is here: http://onlinelibrary.wiley.com/doi/10.1002/2017GL074998/full http://onlinelibrary.wiley.com/doi/10.1002/2017GL074998/full. "Detection of intact lava tubes at Marius Hills on the Moon by SELENE (Kaguya) Lunar Radar Sounder" Intact lunar lava tubes offer a pristine environment to conduct scientific examination of the Moon's composition and potentially serve as secure shelters for humans and instruments. We investigated the SELENE Lunar Radar Sounder (LRS) data at locations close to the Marius Hills Hole (MHH), a skylight potentially leading to an intact lava tube, and found a distinctive echo pattern exhibiting a precipitous decrease in echo power, subsequently followed by a large second echo peak that may be evidence for the existence of a lava tube. The search area was further expanded to 13.00–15.005°N, 301.85–304.01°E around the MHH and similar LRS echo patterns were observed at several locations. Most of the locations are in regions of underground mass deficit suggested by GRAIL gravity data analysis. Some of the observed echo patterns are along rille A, where the MHH was discovered, or on the southwest underground extension of the rille.

samstave 9y ago
If the moon had ancient volcanic activity and thus, why is it, after observable impact from various bodies - shown in the craters all over the surface, and the sumizing of the fact that water was deposited to earth from extra-orbital impacts... does the moon have zero water or atmosphere? Where did water originate? (I didn't know how to format that question any better, so please forgive the fumbly format)
- wyager 9y ago
  The moon’s gravity isn’t strong enough to hold water vapor or any other atmospheric gas. It would either get siphoned off by the earth or just fly off into the solar system. The same is true of earth and helium.
  - samstave 9y ago
    Ok, and I like the comment about helium... But where did water originate?
    - dsr_ 9y ago
      https://cosmologyandspace.wordpress.com/tag/oxygen/ https://cosmologyandspace.wordpress.com/tag/oxygen/ answers your question. If you are trying to go back to "why is there anything?", then the answer is "we don't know precisely, but we do know that if those things hadn't happened, we wouldn't be asking the question, so so we have no basis of knowing whether it's random, rare, or a near-certainty for a new universe."
    - lrdd 9y ago
      I think the short answer is we don't really know, but the simplest explanation is muddy icy comets colliding
      - samstave 9y ago
        If that's the case, why haven't we been hit by any in recorded history that gave us more water? How many comets have hit us that were rife with water supplies to provide the amount of water earth has given that water isn't also abundant on planets that are much larger, like Jupiter? Why do we see planets with atmospheres of say sulfer, and earth doesn't have an issue with sulfer in the atmosphere?
        Turing_Machine 9y ago
        "If that's the case, why haven't we been hit by any in recorded history that gave us more water?" Most of the comets whose orbit intersects with Earth's orbit collided eons ago. Some comets still enter the inner Solar System, of course, but it's going to be extremely rare for one to be on the right path to hit the Earth.
  - NegativeLatency 9y ago
    Also it doesn't have magnetic fields like the earth does to shield its gas from being pushed off by solar wind.
- kurthr 9y ago
  The same place that water came from on Earth... comet impacts and residual moisture from the impact that split the Earth-Moon system. Really the same place all planetary water and gas has come from. There's not much left because it mostly boils off due to low pressure, but in dark crevasses it's likely to stay cold enough to remain condensed. It's been measured spectroscopically.
  - samstave 9y ago
    Where did the comets get the water they impacted on earth?
    - comicjk 9y ago
      Stars produce oxygen (along with all elements up to iron) during nuclear fusion. If the star is big (several times bigger than our sun), it eventually explodes and the oxygen then winds up in interstellar gas and dust. The oxygen reacts with hydrogen to make water. Eventually you wind up with a lot of dirty snowballs floating around (comets). Oxygen is pretty common and hydrogen is everywhere, so water (as ice) is not scarce in the universe. The only place where water is uncommon is near a star, like us, where the water boils off into space unless a planet has enough gravity to hold it in.
    - gjjrfcbugxbhf 9y ago
      Water is just hydrogen plus oxygen. Both are fairly common elements in the universe.
      - samstave 9y ago
        Under what circumstances does one need to have in order to make them combine into water, organically? (Meaning without any device or machine, assume you have two big clouds of each element floating in space - if they collide, do the naturally just form into water molecules?)
        Retric 9y ago
- spdustin 9y ago
  The moon's core isn't made of the swirling molten iron dynamo like Earth's is. No swirling molten iron, no magnetic field. No magnetic field, nothing deflects the solar wind that then, literally, blows away any fledgling atmosphere. It's believed that Mars' atmosphere was considerably more dense than it is today, but along the way, its core cooled, and it lost its protective magnetic shield, allowing the solar wind to strip away much of its atmosphere.
  - kirillkh 9y ago
    Then we have no hope of ever engineering Mars to have enough air for us to breath?
    - LeifCarrotson 9y ago
      A Martian atmosphere (not sure about a lunar atmosphere) would be lost on a timescale of tens of millions of years. That's very quick in cosmological timescales, but slow enough that any human effort to create or replenish it could be very successful.
      - waegawegawe 9y ago
        That said, the earth's atmosphere has a mass of about five billion billion tons. For reference, as a species, we produce about ten billion tons of concrete each year. This is just to give a sense to the scale of effort involved in replacing a planetary atmosphere.
        larkeith 9y ago
        Depending on the volume of surface ice (especially at the poles), might it be possible to produce atmosphere on a massive scale via orbital lenses or mirrors? With recent advances in solar sail technology, I can't imagine the implementation would be too far removed from current capabilities.
        9y ago
- Brybry 9y ago
  I saw a recent study that said the moon probably did have atmosphere from volcanic activity... but only for around 70 million years. It dissipated into space. http://www.sciencedirect.com/science/article/pii/S0012821X17304971 http://www.sciencedirect.com/science/article/pii/S0012821X17...

by yosyp 9y ago

samstave 9y ago

If the moon had ancient volcanic activity and thus, why is it, after observable impact from various bodies - shown in the craters all over the surface, and the sumizing of the fact that water was deposited to earth from extra-orbital impacts... does the moon have zero water or atmosphere? Where did water originate? (I didn't know how to format that question any better, so please forgive the fumbly format)

wyager 9y ago
The moon’s gravity isn’t strong enough to hold water vapor or any other atmospheric gas. It would either get siphoned off by the earth or just fly off into the solar system. The same is true of earth and helium.
- samstave 9y ago
  Ok, and I like the comment about helium... But where did water originate?
  - dsr_ 9y ago
    https://cosmologyandspace.wordpress.com/tag/oxygen/ https://cosmologyandspace.wordpress.com/tag/oxygen/ answers your question. If you are trying to go back to "why is there anything?", then the answer is "we don't know precisely, but we do know that if those things hadn't happened, we wouldn't be asking the question, so so we have no basis of knowing whether it's random, rare, or a near-certainty for a new universe."
  - lrdd 9y ago
    I think the short answer is we don't really know, but the simplest explanation is muddy icy comets colliding
    - samstave 9y ago
      If that's the case, why haven't we been hit by any in recorded history that gave us more water? How many comets have hit us that were rife with water supplies to provide the amount of water earth has given that water isn't also abundant on planets that are much larger, like Jupiter? Why do we see planets with atmospheres of say sulfer, and earth doesn't have an issue with sulfer in the atmosphere?
      - Turing_Machine 9y ago
        "If that's the case, why haven't we been hit by any in recorded history that gave us more water?" Most of the comets whose orbit intersects with Earth's orbit collided eons ago. Some comets still enter the inner Solar System, of course, but it's going to be extremely rare for one to be on the right path to hit the Earth.
- NegativeLatency 9y ago
  Also it doesn't have magnetic fields like the earth does to shield its gas from being pushed off by solar wind.
kurthr 9y ago
The same place that water came from on Earth... comet impacts and residual moisture from the impact that split the Earth-Moon system. Really the same place all planetary water and gas has come from. There's not much left because it mostly boils off due to low pressure, but in dark crevasses it's likely to stay cold enough to remain condensed. It's been measured spectroscopically.
- samstave 9y ago
  Where did the comets get the water they impacted on earth?
  - comicjk 9y ago
    Stars produce oxygen (along with all elements up to iron) during nuclear fusion. If the star is big (several times bigger than our sun), it eventually explodes and the oxygen then winds up in interstellar gas and dust. The oxygen reacts with hydrogen to make water. Eventually you wind up with a lot of dirty snowballs floating around (comets). Oxygen is pretty common and hydrogen is everywhere, so water (as ice) is not scarce in the universe. The only place where water is uncommon is near a star, like us, where the water boils off into space unless a planet has enough gravity to hold it in.
  - gjjrfcbugxbhf 9y ago
    Water is just hydrogen plus oxygen. Both are fairly common elements in the universe.
    - samstave 9y ago
      Under what circumstances does one need to have in order to make them combine into water, organically? (Meaning without any device or machine, assume you have two big clouds of each element floating in space - if they collide, do the naturally just form into water molecules?)
      - Retric 9y ago
spdustin 9y ago
The moon's core isn't made of the swirling molten iron dynamo like Earth's is. No swirling molten iron, no magnetic field. No magnetic field, nothing deflects the solar wind that then, literally, blows away any fledgling atmosphere. It's believed that Mars' atmosphere was considerably more dense than it is today, but along the way, its core cooled, and it lost its protective magnetic shield, allowing the solar wind to strip away much of its atmosphere.
- kirillkh 9y ago
  Then we have no hope of ever engineering Mars to have enough air for us to breath?
  - LeifCarrotson 9y ago
    A Martian atmosphere (not sure about a lunar atmosphere) would be lost on a timescale of tens of millions of years. That's very quick in cosmological timescales, but slow enough that any human effort to create or replenish it could be very successful.
    - waegawegawe 9y ago
      That said, the earth's atmosphere has a mass of about five billion billion tons. For reference, as a species, we produce about ten billion tons of concrete each year. This is just to give a sense to the scale of effort involved in replacing a planetary atmosphere.
      - larkeith 9y ago
        Depending on the volume of surface ice (especially at the poles), might it be possible to produce atmosphere on a massive scale via orbital lenses or mirrors? With recent advances in solar sail technology, I can't imagine the implementation would be too far removed from current capabilities.
        9y ago
Brybry 9y ago
I saw a recent study that said the moon probably did have atmosphere from volcanic activity... but only for around 70 million years. It dissipated into space. http://www.sciencedirect.com/science/article/pii/S0012821X17304971 http://www.sciencedirect.com/science/article/pii/S0012821X17...