Desktop Project Part 1: A weird Moon crater

By Phil Plait | March 26, 2012 7:00 am

[Over the past few weeks, I’ve collected a metric ton of cool pictures to post, but somehow have never gotten around to actually posting them. Sometimes I was too busy, sometimes too lazy, sometimes they just fell by the wayside… but I decided my computer’s desktop was getting cluttered, and I’ll never clean it up without some sort of incentive. I’ve therefore made a pact with myself to post one of the pictures with an abbreviated description every day until they’re gone, thus cleaning up my desktop, showing you neat and/or beautiful pictures, and making me feel better about my work habits. Enjoy.]

First up in my Desktop Project is a weird crater on the Moon, seen by the Lunar Reconnaissance Orbiter:

What a strange little thing! [Click to enlunenate.]

It’s about 140 meters across the rim, and it’s located in Plato, a big, relatively flat walled plain — basically, a crater that got mostly filled in with lava long ago — about 110 km (70 miles) across. You can see rubble and other debris scattered around it (in this image, sunlight is coming from below and to the left), and the interior is just odd.

This is called a bench crater, where you get roughly concentric features inside the crater itself. It’s probably from a high-velocity impact by a small (5-meter or so) asteroid, and the terrain where it hit probably has a thin layer of compacted regolith — the powdery surface material covering a lot of the Moon. This loose material blasted out more than the harder rock below, so you get this weird two-tiered structure.

Craters can be pretty complex; you might think you just get bowl, but in fact the impact speed, angle, the terrain, and the overall size of the impactor make a huge difference in crater structures.

Also? The first thing I thought of when I saw this picture was that it looked like the plaster cast they made of the giant ant footprint in one of my favorite movies of all time, "Them!" And that makes me a bigger dork than you can ever hope to be.

Image credit: NASA/GSFC/Arizona State University

CATEGORIZED UNDER: Astronomy, Pretty pictures

Comments (25)

  1. Big G

    Dear BA,

    Sorry to post this comment here, it has nothing to do with the picture (awesome by the way…)

    Here is the ad that I got from google while reading this post :

    http://the-end.com/2008GodsFinalWitness/?gclid=CL_Ri8jXhK8CFUld3wodWXop2w

    Kind of ironic on BA !!!!

    Cheers

    G

  2. TerryS.

    Phil,

    “I’ve therefore made a pact…to post one of the pictures…every day until they’re gone.”

    That’s assuming that over the next few weeks you won’t be collecting any others. A very precarious prognostication at best!

  3. Peter Davey

    H G Wells, in “The First Men In The Moon”, made his Selenites insectile.

    Nature imitating Art?

  4. NCSmith

    If you are falling behind in some of your plans, you can improve your posting efficiency by avoiding constructions like “metric ton”. “Tonne” works just fine, and saves keystrokes.

    A keystroke is a terrible thing to waste!

  5. FAMOUS ASTRONOMER SAYS, GIANT ANTS ON THE MOON!

  6. Scott P.

    Okay, my eyes refuse to see this as an indentation. Looks like a circular mountain to me. I know that the eye tends to read objects as if light is coming from above, but even when I rotate the image 180 degrees I still see it as convex.

  7. Dr.Sid

    For me the rotation helped .. but I still can’t see it as ‘crater’ like this ..

  8. Owahay

    I’m fascinated by the concentric rings crossed by parallel lines about one radius straight up from the top of the crater’s edge, along the lower rim of the darker (older) crater above this one.

  9. Tim Kuzniar

    Great shot, Phil..! And I don’t know about who’s a bigger dork — I thought of the “Them” footprint likeness before you mentioned it……

  10. Mike

    I still won’t go into the flood control channels of L.A. because of “Them”.

  11. I was first able to recognize it as a hole, rather than a mountain, when rotated 90-degrees counter-clockwise. At first, everything looked like mounds, rather than craters. Once I was able to get the small craters to look indented, the big crater followed suit. Now, I can’t even un-indent it!

  12. Are you sure it isn’t a fresh, new small crater inside an old, weathered crater?
    That’s what it looks like to me…
    Cool looking crater either way.

  13. It’s a piggy’s face, smiling at me!

    See the piggy ears at the top, and the snout in the middle?

  14. buddz

    “Them” was one of the finest giant-atomic-ant documentaries of all time. And Phil, you get major points for appreciating it.

  15. Grand Lunar

    “The first thing I thought of when I saw this picture was that it looked like the plaster cast they made of the giant ant footprint in one of my favorite movies of all time, “Them!” And that makes me a bigger dork than you can ever hope to be.”

    Is it that you thought of that that makes you a bigger dork than I could ever hope to be?
    :)

    Anyway, I did experience that famous optical illusion where one think that a depression is a dome. I know you wrote about that once on your site. What’s that illusion called again?

    Nice picture, BTW!
    I doubt you’ll run out….

  16. kat wagner

    It’s an outtie.

  17. Meskine

    Please tell me you’re referring to the original “Them” with James Arness (My second favorite 1950’s sci-fi B movie behind the original “The Blob” with Steven McQueen). If not, you’re just a wannbe peeking through the front window fantasizing about how glorious it must be to be a real dork.

  18. Messier Tidy Upper

    @1. Big G : I could be mistaken but I don’t think the BA has any control or even any influence over what ads appear here. Think its some automated computer thingummywhatsit that generates them. Same thing happens on a number of other blogs too, not just the BA blog.

    But, yeah, its a bad match up of ad to audience – and a bad ad period!

    ***

    Strange crater indeed. Wonder what it would be like if we could see it from the lunar surface? Wonder if and when anyone will visit it in person – maybe take samples of it – one day?

  19. I dunno, I saw “Them!” at the Insect Horror Film Festival while munching on corn-borer corn bread and pop corn sprinkled with tiny insects, you may not be the biggest nerd of them all. I’m pretty sure I also saw it ~15 years later at the Dryden Theater in the George Eastman House….one improptu festival showing, one full-on theater showing.

    Boy, this post is going to get more commentary about Them! than anything else.

  20. don gisselbeck

    It took me several minutes to see craters as indented. I had to magnify the image and focus on the rocks to the lowere left of the crater. I had a similar problem seeing the Hadley Rill as a valley in a video of a lunar lander lift off.

  21. Roger Wilco

    While we’re talking about tonnes, I’m sure you know, BA, that a “Metric Ton” is only about 10% bigger than a common or garden “American” ton. People seem to think the expression means megaton or something :-)

  22. Its an old scar from a surgically removed Borg implant, the same type that comes popping out of Picard’s face in the dream in Star Trek First Contact.

  23. Nigel Depledge

    Roger WIlco (21) said:

    While we’re talking about tonnes, I’m sure you know, BA, that a “Metric Ton” is only about 10% bigger than a common or garden “American” ton. People seem to think the expression means megaton or something

    Heh. Interestingly, the Imperial ton is a little bigger again than the tonne.

    So, the “American” or “short” ton is 2000 lbs;
    The “metric” tonne (incidentally, AFAICT this always takes the French spelling) is 1000 kg or (as near as makes no never-mind) 2205 lbs;
    The Imperial ton (sometimes called the “long ton”) is 2240 lbs, or 20 cwt.

  24. Stan9fromouterspace

    “Them” was just on the AMC channel a few days ago. Great cast, cheesy effects and a couple of nice juicy Wilhelm screams. Good times.

  25. B-sson

    Phil, just a funny thing. When “Them” went up to teathers at that time in Sweden it was named “Spindlarna”. It means spiders in Swedish. Apparently the promoter didn´t find ants that terrible.

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