As from above, so from below

By Phil Plait | January 10, 2012 7:00 am

NASA’s Earth Observatory site just put up this amazing picture. I have to say, this is one of the cooler pictures from the International Space Station that I’ve seen. Not for it’s beauty or anything like that — though it is starkly lovely — but because of what it shows:

[Click to dicraternate.]

Obviously, that’s a volcano on the right: Emi Koussi, in northern Africa. But look to the left, almost at the edge of the picture. See that faded ring? That’s Aorounga — an impact crater, some 10 – 15 km wide, formed when a chunk of cosmic debris hit the Earth about 300 million years ago! So these are two craters, one formed from processes happening deep below the Earth, and one from events from far above. Yet both can be seen at the same time, from one vantage point: orbiting our planet somewhere above the surface but beneath the rest of the Universe.

Image credit: NASA

Related posts:

A long, thin, volcanic plume from space
UPDATE: more amazing Nabro volcano images
Staring down an active volcano’s throat
Volcano followup: pix, video

CATEGORIZED UNDER: contest, NASA, Pretty pictures

Comments (24)

  1. Very cool. When this post first popped up, I almost thought it was a picture of Mars instead of home. :)

  2. Chris

    @1 Larian
    Same here.

  3. Jason

    Great image.

    Perusing google maps the other day I came across this feature at 23.95N, 111.6E.,111.6&safe=on&um=1&ie=UTF-8&hl=en&sa=N&tab=wl

    Impact crater? Extinct volcano? Or just a curious mountain range?

    Any ideas?

  4. This_Guy

    What is the white blob inside the volcano crater? Snow? Water? The second ship from Area 51 censored out? ūüėÄ

  5. OtherRob

    Add me to the “I thought it was Mars” crowd.

  6. Jeffersonian

    Well that IS pretty cool.
    Pyroclastic Shields are cool [pun!] and somewhat unique. This one is the highest elevation in the entire Sahara. Damn fool thing is 40 miles across. Note the newer caldera nested in the old.

  7. Aaron

    What are the (somewhat) vertical lines on the left side of the picture? Caused by wind?

  8. LJA

    If I wasn’t told anything else and was presented this photo, I’d have said it was some type of small hot spot with the crust moving over it.

  9. Satan Claws

    Just checked the terrain with Google Earth. That place is CRAZY beautiful! There are also other calderas further to the Northwest of Emi Koussi. And add me to the crowd that mistook it for Mars.

  10. What stood out to me were the nearly parallel lines running down the left side of the photo. Is that due to the volcano or some other process?

  11. Wzrd1

    I’m wondering if that is a double impact crater. The heavily eroded one is plain to see, but there appears to be a larger crater surrounding it, pretty much out of frame.
    On Google Earth, it looks like another possible heavily eroded impact crater west-southwest of this impact crater.
    To see what I’m looking at, go from the center of the small impact crater with a heading of 239.9 degrees for 90.26 KM. The other possible impact point is around the small impact crater and appears 58KM across, though it could be an illusion.

  12. Fabio Miguez

    I went looking for more info and found an interesting website: Basically they consider the possibility that this crater was formed by an exceedingly large electric discharge. Sounds odd and unlikely to me, especially considering I have never heard any prominent, established scientific source even mention this. I am at work and have no further time for investigation, but I am wondering if someone in here had more information about that process?

  13. Trebuchet

    You get some bonus pareidolia: There’s a rather sad face in the volcano if you rotate it 90 deg CCW!

    Just from curiosity, how can we tell the second crater is an impact crater, not a highly eroded older volcano?

  14. JimTKirk

    There also looks like a 5-6 KM crater to the left and some smaller ones below. Could just be pareidolia on my part though…

  15. Fabio Miguez

    @TechyDad, looking in Google Earth, the lines appear to be all through the Aorounga region in Chad. It might be more to do with plate tectonics, but I’m no geologist :)
    UPDATE: By looking in Google Earth further, I’d have to change that and attribute it to prevaling winds and/or flood plains. If you look just to the NE of the crater you’ll see a series of cliffs, with lots of “channels” cut in them, apparently by the wind. It could be that this is a valley of sorts, channeling the wind in a certain direction, and the lines are the terrain erosion caused by it. Just guessing, though.

  16. lovecraft

    I immediately figured out what they are just by looking at the photo. So that makes me what ?

  17. Wzrd1

    @Fabui Miguez, the lines are typical with wind erosion, as can be seen from the extended lines behind obstructions. Even money, the wind is guided by the mountain range to the north, but I’d have to look up prevailing winds for the area to be certain.
    There DOES appear to be some rift activity in that area as well and I recall reading some time back about some upwelling in the mid-African continent, this might be due to that hotspot activity. The area is quite far from the rift valley region and is pretty much in the center of the continent…
    It’s a complicated continent!

  18. Randy A.

    As Wzrd1 points out, the lines are due to the prevailing winds in the region.

    It should also be pointed out the “crater” and “caldera” are not synonyms. A crater forms from an explosion — meteorite impacts and volcanoes both cause explosions.

    A caldera forms when the top of a volcano collapses down into a partially emptied magma chamber. Crater Lake in Oregon is an example. The volcano in this picture has a beautiful example of a caldera.

    As the text accompanying the picture at NASA’a Earth Observatory points out, there is a smaller crater inside the caldera. The bottom of the crater is white — probably salts.

  19. Chris A.

    When I read the title I thought that Phil was going to write about how astrology was from hell, since it’s a play on words based on the proffered guiding principle of that pseudoscience. XD

    Here’s a challenge: Is there anywhere on Earth where you can find an impact feature on top of (i.e. whose formation postdates) a volcanic feature? (I don’t know of any, but then again I’m not a geologist.) I’m guessing there may not be any, just because volcanic features tend to be short-lived over geologic time scales.

  20. Wzrd1

    Fabio, I finally got the chance to look at the site you posted. That is a pseudoscience site that links off of some rather out there theories. They propose that electricity is the prime source of energy on the sun and that planets arc to each other and all manner of other fringe, unproven and unlikely things.
    One example is that the site claims that a nova is caused by fissioning of a double charged layer, which is itself some other pseudoscience with zero facts, experimental evidence or observations to support such inane notions.

  21. Checkmate1

    That crater has survived 300 million years of plate movement, volcanoes, wind, and dinosaurs… and is still visible? Since before the Permian era?
    Color me impressed with the tenacity of that hole in the ground! What kind of rock is that?

  22. Great picture. As another commenter said above, I really did initially feel as if I was looking at Mars. Very cool.

  23. itskurtins

    I was wondering if you saw any info on a nickel iron impact crater in upper Egypt (remember upper Egypt is in the south) that was created by an impact 5,000 years ago. It was found by some one looking at Google earth, and then documented by an expedition to the site. it is a small crater, but given the environment in the desert there it has survived as if it was created yesterday. The study was published in Science Magazine, and afterward I was surprised you didn’t mention it. They gave the co-ordinants, but I could not find it on Google earth my self. The study was in a report so its behind firewall. But the impact happened within historical times, but I guess the Egyptians were to busy with their pyramids, and left no records of the impact.

  24. Wzrd1

    Itskurtins, it COULD have remained undocumented due to either document loss or more likely, sparse population at that time.
    There also is a triple crater in Saudi, in the empty quarter. It fell within the modern historic times (1863 or so), the fireball observed and recorded. The meteors finally located in 1932 by Philby. The site was unable to be located by one expedition since and several after have managed (barely) to locate it and retrieve specimens, the last being 1994-1995 series that destroyed quite a few of the expedition vehicles, due to the harsh environment of the empty quarter.
    Total mass estimate was 3500 tons, which broke into four fragments, two of which were recovered (one weighing 2.2 tons). Hundreds of fist sized fragments remain on that remote and difficult site.
    It’s also said that one “blessed” stone embedded in the Kaaba in Mecca is of meteoric origin, though that remains unconfirmed.
    There are a number of other impact craters throughout the middle east, some of which were recorded in history of being excellent sources of iron.
    Not to mention the famous Damascus swords, which were made from meteoric iron from a meteor in India.


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