Cratering on Mars

By Phil Plait | December 7, 2006 12:08 pm

I mentioned yesterday that besides water, the other interesting news from Mars Global Surveyor (MGS) is that they spotted lots of new craters, too (a crater in a new image was not in an older one). This allowed the scientists to determine the rate at which new craters are made, and they found that craters are created at a rate of about one per month. These aren’t dinky ones either– one they showed was the size of a football stadium!

Here’s a before-and-after shot of a new crater in Arabia Terra in Mars’ northern hemisphere:

It was created some time between January 1, 2004 and February 22, 2006. You can see the impact debris (what we astronomers in the know call "ejecta") spread out over an area a kilometer across.

The MGS team also mentioned that if you lived on Mars for about 20 years, on average you’d be close enough to one impact to actually hear it. Given that NASA plans on sending humans to Mars, this is a matter of real concern! It’s a tough problem– these are rocks that are maybe a few meters across, and so there is almost way to detect them. I have no idea how you could reliably find a large enough number of these potential impactors to do anything about them, and you really don’t want one touching down near a settlement.

Anyway for more detail and some cool images, go to Emily’s Planetary Society blog. She’s an actual planetary scientist and has more intelligent things to say about this than I do (you can also see the original images on the Malin Space Science Systems site. Emily also has a statement by the Planetary Society about what all this means for us as humans. It’s a good read.

CATEGORIZED UNDER: Astronomy, Cool stuff, NASA, Science

Comments (13)

  1. The Tarrkid

    “if you lived on Mars for about 20 years, on average youâ€™d be close enough to one impact to actually hear it.”

    Why so frequent, compared to Earth? Is it just that it’s closer to the asteroid belt?

  2. Chris Jones

    I saw the press conference but I haven’t read any press release (or the paper). When they said “close enough to hear it”, was that an earth-centric metric, or do they mean that *on Mars* one would be able to hear it? Given the surface pressure on Mars, I expect sound propagates really badly, but I don’t know for sure.

  3. Flak

    I’m sure the frequency of meteriorite impact is due to both proximity to the asteroid belt and Mars’ low atmospheric pressure. I believe both of Mars’ moons are thought to be asteroids captured from the belt. And with it’s proximity to the belt Mars is sure to just pick up more junk due to gravity and chance. That plus a very thin atmosphere (compared to Earth) that can’t burn up all the meteors… and you get a lot of impact craters. I could be wrong, but that’s my theory.

  4. The Tarrkid

    Oh yeah, I didn’t think about the lower atmospheric pressure. That seems to make sense. Thanks.

  5. Grand Lunar

    Hmm, Mars sounds a bit more dangerous to live on.
    Geez, it’s not enough that the place gets planet-wide dust storms. Now this?!

    I wonder what sort of strategy can be used.

  6. Hey, isn’t that crater in the last known location of the Beagle probe?

  7. George

    Interesting timing. I would expect the impacts would heat the ice below and cause liquid water to ooze out of something…say the side of a larger crater wall. :)

  8. Chip

    Whereas some things in nature seem organized along predictable mathematical lines (such as the Fibonacci series for pine combs,) Mars seems to be organized along the lines of Tarot Cards. (Isn’t this just like Mars?) i.e. “Hey, we have water over here. Great for colonizing. Come on down.” â€“ “Oh and by the way, the trade off is you have a higher chance of getting clobbered by an incoming boulder.” This new finding falls within the interesting and often contradictory history of observation and exploration of the red planet.

  9. Roger

    Forget the water see the face on mars that the Bad Astronomer is helping to cover up. I sent this to him a week ago but got no comment. This is weird but in the new edition of ‘The Planetary Report’ from the Planetary Society is a picture from one of the rovers on page 14. It is in an article by Jim Bell titled ‘Photographing Mars’. The picture of the promontory Cape Verde contains the image of a face.or skull. I’m not kidding at least that’s what it appears to be. Get your copy and look. The image is at the point of the promontory midway from the top and bottom. It is a profile and you can see the mouth, nose and eye socket. The mouth appears to be open as if speaking. I’ll wait while you go look.

    See I told you. How did NASA let this picture slip out? I think it best that you expose this before the nuts get hold of it. I am sure there is a rational explanation of why a giant skull is embedded in the rocks of Mars. Again. I am sure there must be a massive conspiracy involved here somewhere. Although as a devout Pastafarian I am sure hid Noodliness is behind it all.

    I can’t wait to see this in the Weekly World News.

    As I said Phil declined to respond which means he’s part of the cover up.

  10. Roger

    That would be his noodliness. sorry.

  11. Troy

    I know in theory there are some zones on mars that allow the existance of liquid water (a combination of atmospheric pressure and temperature) is there any way to verify the temp and pressure at the location? Obviously liquid water would be a way, but in order to get collaborating evidence it seems it would help.

    It is always interesting to see Mars as a dynamic place, the moon seems so static by comparison. I was particularly thrilled with the animations of dust devils.

  12. Liz

    For some reason I read the headline as Catering on Mars.

    What are they serving? Hors d’ouevres? A buffet? Is there be an open bar?

    Really, that’s got to be one hell of a catering gig.

  13. Troy

    I saw the aforementioned ‘skull’ on page 14. Just a rock, I’m afraid.


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