4 ms·

Meteorites pummel the Moon far more than expected

27 points by Mz 10y ago

ghshephard 10y ago
"Meteorites have punched at least 222 impact craters into the Moon's surface in the past 7 years. That’s 33% more than researchers expected..." It's unclear from the article whether they are saying that they observed 222 impact craters, or calculated that there were 222 impact craters across the moons surface. 222 impact craters across the entire moon over 7 years, is an insignificant number.
- kobeya 10y ago
  Probably observed. Thats about how long we've had continuos satellite coverage.
- geuis 10y ago
  The answer is in the first three words: "have punched". It's stating something that has happened.
- intortus 10y ago
  It's not unclear at all. > Speyerer’s team used a computer program to automatically analyse 14,092 of these paired images, looking for changes between the two. The 222 newfound craters are distributed randomly across the lunar surface, and range between 2 and 43 metres in diameter.
  - ghshephard 10y ago
    I read that paragraph a dozen times before writing my comment. Still not 100% certain that the analysis saw the newfound craters, or calculated that they existed based on visual data (such as splotches). I'm leaning 80/20 to the fact that they visually identified the 222 craters, but I wouldn't give 20:1 odds on it.
    - intortus 10y ago
      What's the difference between seeing and "calculating based on visual data"? If you're looking for live observations of impacts as they happened, this paragraph makes it pretty clear that they're counting "splotches."
      - ghshephard 10y ago
        "Seeing" - You physically see the crater on the moon. "Calculating" - you don't actually see all of the craters, but you can infer, based on various new deposits/splotches of ejecta, that in the time reviewed, that approximately 222 new craters were created on the surface of the moon. The difference between the two, is that in the case of seeing 222 craters, it leaves open the possibly that many others, particularly on the "Dark Side" also occurred. In the case of calculating, it may be the case that they are suggesting that a total of 222 major craters were created during that window of time.
- LeifCarrotson 10y ago
  > 222 impact craters across the entire moon over 7 years, is an insignificant number. It is very significant if you built the ablative meteorite shielding for your spacecraft assuming there would be 1/3rd less meteorites. It would be surprising to me if this error did not affect the entire distribution of interplanetary meteorites.
  - ghshephard 10y ago
    A rare event is still rare, even if it happens 1.3x as often.
ChuckMcM 10y ago
I found this a very interesting paper. But given, 722 impacts over 7 years with a median sized 25 meter diameter crater, that is about 490 m^2 getting hit every 11 days. If such impacts were perfectly randomly distributed that is like 20K years before you have hit everywhere on the planet. You still have a much better shot at getting hit by an natural disaster that destroys your Earth base than this. That said, it does mean you should keep watch for incoming impacts. Even a couple of kilograms of Chondrite coming in at 27,000 miles an hour is going to leave a mark on your fancy moon base. Subterranean safe rooms and auto sealing atmosphere preservation doors are going to be required equipment.
- trhway 10y ago
  >Even a couple of kilograms of Chondrite coming in at 27,000 miles an hour is going to leave a mark on your fancy moon base. simple space/Moon version of anti ballistic missile defense system like Patriot/Aegis/S-400 should take care of it. Especially if armed with small nuclear warhead, there are still a lot of them lying around without any use.
- Patrick_Devine 10y ago
  Given that the moon is tidally locked to the Earth, all you need to do is put the base on the near side of the moon and you'll dramatically reduce the chance of being hit by a meteor. Compare the far side [1] to the near side [2]. [1] https://en.wikipedia.org/wiki/Far_side_of_the_Moon#/media/File:Back_side_of_the_Moon_AS16-3021.jpg https://en.wikipedia.org/wiki/Far_side_of_the_Moon#/media/Fi... [2] https://en.wikipedia.org/wiki/Near_side_of_the_Moon#/media/File:Moon_nearside_LRO.jpg https://en.wikipedia.org/wiki/Near_side_of_the_Moon#/media/F...
  - grogers 10y ago
    Earth being 'in the way' causing fewer meteor strikes doesnt account for the differences between the near and far sides of the moon [1]. It's a fairly small effect apparently. Of course, any moon base would probably be on the near side anyways to communicate with earth. [1] https://medium.com/starts-with-a-bang/the-two-faces-of-the-moon-398fbc85840d https://medium.com/starts-with-a-bang/the-two-faces-of-the-m...

27 points by Mz 10y ago

"Meteorites have punched at least 222 impact craters into the Moon's surface in the past 7 years. That’s 33% more than researchers expected..." It's unclear from the article whether they are saying that they observed 222 impact craters, or calculated that there were 222 impact craters across the moons surface. 222 impact craters across the entire moon over 7 years, is an insignificant number.

kobeya 10y ago
Probably observed. Thats about how long we've had continuos satellite coverage.
geuis 10y ago
The answer is in the first three words: "have punched". It's stating something that has happened.
intortus 10y ago
It's not unclear at all. > Speyerer’s team used a computer program to automatically analyse 14,092 of these paired images, looking for changes between the two. The 222 newfound craters are distributed randomly across the lunar surface, and range between 2 and 43 metres in diameter.
- ghshephard 10y ago
  I read that paragraph a dozen times before writing my comment. Still not 100% certain that the analysis saw the newfound craters, or calculated that they existed based on visual data (such as splotches). I'm leaning 80/20 to the fact that they visually identified the 222 craters, but I wouldn't give 20:1 odds on it.
  - intortus 10y ago
    What's the difference between seeing and "calculating based on visual data"? If you're looking for live observations of impacts as they happened, this paragraph makes it pretty clear that they're counting "splotches."
    - ghshephard 10y ago
      "Seeing" - You physically see the crater on the moon. "Calculating" - you don't actually see all of the craters, but you can infer, based on various new deposits/splotches of ejecta, that in the time reviewed, that approximately 222 new craters were created on the surface of the moon. The difference between the two, is that in the case of seeing 222 craters, it leaves open the possibly that many others, particularly on the "Dark Side" also occurred. In the case of calculating, it may be the case that they are suggesting that a total of 222 major craters were created during that window of time.
LeifCarrotson 10y ago
> 222 impact craters across the entire moon over 7 years, is an insignificant number. It is very significant if you built the ablative meteorite shielding for your spacecraft assuming there would be 1/3rd less meteorites. It would be surprising to me if this error did not affect the entire distribution of interplanetary meteorites.
- ghshephard 10y ago
  A rare event is still rare, even if it happens 1.3x as often.

ChuckMcM 10y ago

I found this a very interesting paper. But given, 722 impacts over 7 years with a median sized 25 meter diameter crater, that is about 490 m^2 getting hit every 11 days. If such impacts were perfectly randomly distributed that is like 20K years before you have hit everywhere on the planet. You still have a much better shot at getting hit by an natural disaster that destroys your Earth base than this. That said, it does mean you should keep watch for incoming impacts. Even a couple of kilograms of Chondrite coming in at 27,000 miles an hour is going to leave a mark on your fancy moon base. Subterranean safe rooms and auto sealing atmosphere preservation doors are going to be required equipment.

trhway 10y ago
>Even a couple of kilograms of Chondrite coming in at 27,000 miles an hour is going to leave a mark on your fancy moon base. simple space/Moon version of anti ballistic missile defense system like Patriot/Aegis/S-400 should take care of it. Especially if armed with small nuclear warhead, there are still a lot of them lying around without any use.
Patrick_Devine 10y ago
Given that the moon is tidally locked to the Earth, all you need to do is put the base on the near side of the moon and you'll dramatically reduce the chance of being hit by a meteor. Compare the far side [1] to the near side [2]. [1] https://en.wikipedia.org/wiki/Far_side_of_the_Moon#/media/File:Back_side_of_the_Moon_AS16-3021.jpg https://en.wikipedia.org/wiki/Far_side_of_the_Moon#/media/Fi... [2] https://en.wikipedia.org/wiki/Near_side_of_the_Moon#/media/File:Moon_nearside_LRO.jpg https://en.wikipedia.org/wiki/Near_side_of_the_Moon#/media/F...
- grogers 10y ago
  Earth being 'in the way' causing fewer meteor strikes doesnt account for the differences between the near and far sides of the moon [1]. It's a fairly small effect apparently. Of course, any moon base would probably be on the near side anyways to communicate with earth. [1] https://medium.com/starts-with-a-bang/the-two-faces-of-the-moon-398fbc85840d https://medium.com/starts-with-a-bang/the-two-faces-of-the-m...