A flower bloom on the Moon

By Phil Plait | May 11, 2011 7:00 am

If I ask you to close your eyes and picture a crater on the Moon, I bet what would come to your mind is a bowl-shaped depression, a raised rim, and maybe a central peak. You might also picture the surrounding area, which looks pretty featureless except for other craters.

I would also bet you wouldn’t picture anything like this:

Isn’t that lovely? [Click to enlunanate.] Looking like a kilometer-wide flower on the lunar surface, it’s an unnamed crater just south of Mare Crisium, on the Moon’s eastern limb near the equator. This image, from the Lunar Reconnaissance Orbiter, spans a distance of about 2.2 km (1.3 miles) across and the full-res image has a resolution of roughly 1.5 meters per pixel.

It’s not your run-of-the-mill crater. It’s surrounded by the material that was ejected when a small asteroid (or comet) slammed into the Moon. The impact excavated something on the order of a million tons of rock, blasting it off the surface and into the sky. The plume was thickest in the middle, right over the crater, and thinned with distance. It settled in those streaks, bright in the center where the material is thickest, and darkening farther away. This material is called the crater’s ejecta blanket.

You can also see two black, smaller craters, one just below the main crater and one a bit farther to the left. They also display small ejecta blankets. Most likely they were formed from secondary impacts; boulders blasted up and out on high trajectories, which then impacted the surface after the plume had fallen. Their impact dug up the older, darker surface material underneath the blanket.

In fact, in the zoomable and pannable wide-angle view of this crater, you can see that the original surface surrounding the crater is quite dark compared to the ejecta blanket. And if you zoom in, you see those two black secondary craters aren’t alone; there are hundreds of smaller, darker spots. Most if not all of them are from secondary impacts of smaller rocks that fell back to the lunar surface.

If you zoom out, you can see some of those light streaks (technically called rays) stretching over 4 km away. When the impactor slammed into the Moon it made a heckuva bang. I expect such an explosion would have been visible from Earth… though this crater probably formed well before there were humans striding the Earth.

Over time – lots and lots of time – erosion will take its toll. The solar wind, micrometeorite impacts, even thermal stress from the Moon’s day/night cycle, all will weather away this crater. The blanket will fade, the crater features will dull, and eventually it will look like the countless other 100-meter-wide holes in the Moon. But who knows? By then, perhaps, a few more will have formed.

Image credit: NASA/GSFC/Arizona State University


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CATEGORIZED UNDER: Astronomy, Pretty pictures
MORE ABOUT: crater, LRO, Moon

Comments (31)

  1. Lars

    Wow. Looks like something from Deluxe Paint V.

  2. Gus Snarp

    Wow, when I first saw it I thought it was a live shot of an impact, the ejecta looks like it could be an active plume rather than lying on the surface.

  3. How old is this crater?

  4. Sam H

    Looked like a freshly ‘asploded volcano to me. Anyway, any ideas for names? Stuff like this deserve them (and I’m unfortunately void of ideas at the moment).

  5. Matthew Marshall

    I wonder if James Bond sleeps under an ejecta blanket?

  6. I suggest naming it Júhuā, which is Chinese for chrysanthemum. Seems appropriate, given that the Chinese will probably be the first ones to visit.

    Oh, Júhuā is also slang for anus, which is sort of appropriate, too, given that – relative to manned space travel – it’s where our head has been stuck for the past 30 years.

    I kid.

    ?

  7. Grand Lunar

    Looks more like “flour” than a flower! :)

    “Over time – lots and lots of time – erosion will take its toll. The solar wind, micrometeorite impacts, even thermal stress from the Moon’s day/night cycle, all will weather away this crater. The blanket will fade, the crater features will dull, and eventually it will look like the countless other 100-meter-wide holes in the Moon.”

    So this is a more recent crater?
    Facinating! I wonder what the surface view would be like here…..

  8. It looks like someone sneezed.

  9. Tail

    Looks more like splat than slam. Kinda like the surface was damp, or whatever hit it was.

  10. Blizno

    That is beautiful and terrifying at the same time. The energies required to make that happen….

  11. Stan9fromouterspace

    Grand Lunar’s comment about flour sounds about right; it looks as if the impactor must have been a very loosely held together mass, as opposed to a solid rock. Looks like a mark left by an old bag of flour used as a practice bomb for training purposes, such as I have seen in some TV shows & such. May not have happened in real life, but it was an effective demonstration, left a big SPLAT mark on the ground, and no real crater or collateral damage. Cometary impact, as opposed to a solid meteor? Might be a good place to look for hydrocarbons, ice, organic compounds…

    If we ever go back.

  12. Keith Bowden

    Am I the only one who thinks it really looks more like a “Júhuā”? [Thank you kunigget for the euphemism!] C’mon it even has ejecta!

    Seriously, I love the variety of styles for impact craters. The moon has an interesting history all its own.

    And as a wise critter once said, “That’s all right, he can call me a flower if he wants to.”

  13. @ Keith:

    So you’ve been “mooned”?

  14. elly

    Ack! It’s the lunar eye of sauron!

  15. mike burkhart

    Yes it dose look like a flower maybe theres flower power on the Moon .Peace man! Ok enough of the 60s stuff. Before the space age and the Apollo landings many Astronomers thought there would be no erosion on the Moon after all there is no wind (air) or water on the Moon , witch are the two bigest causes of erosion on Earth. But it is now known that there is erosion on the moon caused by Solar wind and gravity. The erosion on the Moon is slower then erosion on Earth.

  16. Keith Bowden

    @kuhnigget: Apparently. And – “Ni!”

  17. Oh, what sad times are these when passing ruffians can say Ni at will to anonymous internet commentators.

  18. Marcus Dunning

    I know we are actively tracking and searching for near miss/hit asteroids for the earth but are people looking for objects that will impact the moon? Is it a concern? Or simply and interesting firework show?

  19. Wzrd1

    Enough, you two! You shall get your shrubbery!

  20. jph

    “two black, smaller craters, one just below the main crater”

    let me guess, that smaller one is only two meters wide?
    Thats no moon…

  21. @^ Wzrd1 : Wait .. Don’t they have to cut down a tree with a herring first!? ;-)

    @13. mike burkhart :

    Yes it does look like a flower maybe there’s flower power on the Moon. Peace man! Ok enough of the 60′s stuff. Before the space age and the Apollo landings many Astronomers thought there would be no erosion on the Moon after all there is no wind (air) or water on the Moon , witch are the two bigest causes of erosion on Earth. But it is now known that there is erosion on the moon caused by Solar wind and gravity. The erosion on the Moon is slower then erosion on Earth. [Emphasis addded.]

    True but (unless you’re including them under gravity which is a bit of a stretch) you forgot to note micrometeorite impacts which are perhaps the most important lunar weathering processes there. Apparently electrostatically raised dust is a significant factor too, If I Recall Right.

    What a blooming great crater and image. Very different and splendid. 8)

  22. Messier Tidy Upper

    See :

    Electrostatic Erosion Mechanisms on the Moon

    Electrostatic Erosion Mechanisms on the Moon
    P. D. Grannis

    Center for Radiophysics and Space Research, Cornell University Ithaca, New York

    The electrostatic processes which have been suggested by Gold as being responsible for erosion of the lunar features are evaluated. The statistics of the charge build-up on the grains of lunar dust due to the solar gas streams are considered. On the basis of the derived probability distribution for grain charge, the electrostatic hopping effect is shown to result in an erosion rate which is lower by a factor of at least 102 than that rate indicated by observations of the moon. It is found that, owing to the supporting action of the electronic space charge, positively charged dust grains may be levitated above the surface. The mass transport resulting from the ‘downhill’ gliding of such levitated grains may be sufficient to explain observed lunar erosion.

    Received 5 August 1961; .

    Citation: Grannis, P. D. (1961), Electrostatic Erosion Mechanisms on the Moon, J. Geophys. Res., 66(12), 4293–4299, doi:10.1029/JZ066i012p04293.

    Source : http://www.agu.org/journals/ABS/1961/JZ066i012p04293.shtml

    & from here :

    http://www.space.com/8744-sun-stirred-lunar-dust-wear-moon-machines.html

    The idea is that sunlight striking the lunar soil strips some molecules of their electrons, “ionizing” them and imparting a positive electrical charge. Since like charges repeal, the dust particles push away from each other, with some lofting as far as tens of kilometers above the moon’s surface.

    On the dark side of the moon, electrons get dumped by the solar wind and likewise generate such lunar “dust fountains.” At the terminator, or the line between night and day, these opposite charges should also cause a flow of dust, Murphy said, affording dust another avenue to foul equipment.

    This link to an article on the Lunar Dust Fountains :

    http://www.space.com/8715-mysterious-moon-light-glowing-dust-fountains.html

    Provides more info on this phenomenon too. :-)

  23. Esmeraldino

    Crater Phil Plait !!!

  24. ColonelFazackerley

    @Gus Snarp
    That’s exactly what I thought: It looks like the ejecta is still moving. I guess becuase the ejecta is deposited in lines that look like motion blur lines in a photo. the dark pock-marks of subsequent impacts look like bits of debris that where thrown almost straight up, so are not moving with the same angular speed (from the camera’s POV).

  25. That’s no moon its a … oh you get the rest of the joke. It just looks like a still frame of an explosion to me. So I put the two together.

  26. Calli Arcale

    When I first looked at it, I didn’t think “flower” — I thought “flour”. That totally looks like my countertop after I’ve first dropped the bread dough onto the floured surface. That’s not really surprising; flour’s another dry, powdery substance.

  27. Messier Tidy Upper

    @ 21. Calli Arcale : But a flower isn’t usually dry & powdery! Unless its been pressed & dried. ;-)

  28. CR

    At first glance, this looked to me like an explosion, very reminiscent of a WWII combat photo showing a Japanese bomb just exploding on impact with a US aircraft carrier flight deck. Sorry I don’t have a link; I’ve seen the pic in several books over the years… y’all remember books, don’t you? Some sources claim that the bomb killed the photographer, but later sources claim that the photographer lived. Anyway, that’s one thing I thought of.

    Another was a water balloon bursting directly overhead, but that would have to be one HUGE water balloon to make a spray pattern that fine.

    A final ‘other’ thing this reminded me of was aurora. Sure, we all know about the shimmering curtain-like aurora that most people think of, but occassionally, when one of those ‘curtains’ is directly overhead, portions of it look a little bit like this pic, with streaks appearing to radiate from (or disappear into) a distant vanishing point. (I’ve actually used the water balloon imagery to describe the effect to people who missed the events.)

  29. Wzrd1

    Personally, I’d love to get some core samples from the impact area and the surrounding area. Some of the deeper strata would be exposed and some remnants of the impactor would also be present for analysis.

  30. Chip

    At the very center it looks like much rougher ground with big boulders. It would interesting to hike through there. (In spacesuits of course.)

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