Space tweeting

By Phil Plait | March 13, 2010 7:28 am

A few weeks ago, International Space Station astronaut Soichi Noguchi took an amazing picture of Endeavour re-entering Earth’s atmosphere.

He has been busily snapping away at the Earth and posting the pictures on his Twitter feed. You really should be following him!

Recently, he unknowingly did me a big favor by posting this incredible shot of Egypt:


Yes, those are actual pyramids in the picture! Amazing. And by doing that, he made it very easy for me to answer the question I still get about once a month from people: "Is the Great Wall of China the only man-made object you can see from space?".

I already knew the answer is no; you can see cities easily, as well as agricultural formations, big roads, and more. But this one shot makes it very plain and simple: yes, humans have made quite an impact on the planet, and you can easily see it from space.


Comments (49)

  1. Mchl

    The version I heard is that the Grat Wall of China is the only structure visible from the Moon. And not the Wall itself, but rather a difference in color of ground on both sides of it…

    How much truth is in there I do not know. Better ask Buzz.

  2. Pi-needles

    Recently, he unknowingly did me a big favor by posting this incredible shot of Egypt:

    Unknowingly BA? Are you sure this wasn’t a pyramid scheme you two cooked up together? ūüėČ

    PS. Actually, if I recall right, I think you cannot see the Great Wall of China either from the Moon (from where you’d be lucky to make out the Earth’s continents – I think one of the astronauts noted he could block out the whole Earth behind his thumb) or even Low Earth Orbit – but I could be wrong.

  3. Concerned Nerd

    I don’t quite understand this “only ____ which can be seen from space” statement. Seen with what: the human eye, an astronaut with a 20x zoom camera in low earth orbit, a spy satellite?

  4. JenniferBurdoo

    The difference in color is visible between a number of countries, particularly those with differing environmental polices. Haiti and the Dominican Republic, for example.

    One artificial structure (the largest) that isn’t obvious at all, unless you know its source, is the coastline of Holland — All manmade, differently shaped, and visibly deeper into the North Sea than it was a thousand years ago.

  5. Ron1

    There’s an awful lot of detail in that photo? Although I don’t doubt the pyramids are visible with the naked eye from the ISS, I’m not so sure about about the buildings and minor roads. Do you have any idea if Noguchi was using a zoom lens or other form of magnification, if so, what level of magnification?

  6. Stephen P

    To amplify Jennifer’s comment, check out this link.

    The two big polders there are entirely artificial – they were water 75 years ago. Check the scale. As far as visibility from space is concerned the Great Wall is a non-starter in comparison.

  7. Mchl

    Jennifer, Stephen: Thanks! I’ve never considered Netherland’s polders when pondering about Great Wall’s visibility from the Moon, and it certainly makes much more sense to me. Personally I also find it much more awesome, than the Great Wall.

  8. Bad Albert

    It’s hard enough to recognize the Great Wall on Google Earth. I don’t see how it can be visible from orbit.

  9. Pierre

    I found them on Google Earth.

    29d 48′ N, 31d 12′ E

    I was quite lucky there… I just visually scanned the boundary between the Nile’s green lands and the sandy sections, and it took me 2 minutes to find them.

  10. Pierre

    Ron1, I was wondering how difficult it would be to take such a picture,
    so I just rescaled the geometry to help me visualize the feat.

    The pyramids are 2km apart, the ISS is 400 km above and moving 8km/s
    on its orbit (roughly). Scale all of this using 1cm per km. You can draw
    the pyramids on a post-it as two large dots , 2cm apart. Glue the post-it
    on your wall and stand 4 meters away. Now, what kind of camera can
    get you the kind of framing we see above? One with a large zoom.

    Also, you have to remember that the sheet of paper is moving sideways
    on your wall at 8cm per second… better aim fast!

  11. Those are the pyramids of Dashur. They are some of the oldest monumental stone structures on the planet. The oldest one (the smaller one to the lower left, with the wee pyramid beside it) was built about 4600 years ago. It’s called the “bent” pyramid because the lower courses of stone ascend at a much steeper angle than the higher courses, presumably because the ancient builders recognized signs of stress as they built higher, and adjusted the angle accordingly so the pyramid wouldn’t collapse. A nice example of reasoned thinking and adaptation.

  12. Not with the naked eye I think that’s taken with a 300mm lens.
    NYC skeptics

  13. Randy Griffin

    I’ve seen other photos on Universe Today that stated they were taken with an 800mm lens.

  14. Tom

    I just wrote up something on my blog site last night about Soichi’s stuff also! Click my name above to see mine. Not much different, leads to the same photos, but it’s still very cool to see that cupola used this way.


  15. Dan Gerhards

    Most astronauts agree that you can’t even see The Great Wall of China from low Earth orbit, let alone the moon. According to Wikipedia, that rumor was started by an archaeologist in 1754! Obviously, it was only a guess. It was a bad guess too–it’s equivalent to seeing a human hair from two miles away.

  16. Length of one side of pyramid base (Red Pyramid, from Wikipedia – it is a truth universally acknowledged that Wikipedia is never wrong) 220m;
    Height of ISS 278 – 460km (also Wikipedia);
    while we don’t know the height at the time of the photo, we are justified for the general question in taking the minimum (and, depending on your definition of the edge of ‘space’, could go lower);
    angle subtended by one side when vertically over the pyramid: 220/278 milliradians or about 3 arcminutes.

    Visual acuity is based on 1 arcminute as standard for things like 20/20 vision (Wikipedia again, admittedly for black on white) – no doubt this is a complex subject, but there seems a fair margin here.

    For comparison, the long axis of Mare Crisium on the Moon is about twice this, and easily visible to the naked eye.

    So it looks as if the photo does quite a bit better than the naked eye (a truly naked eye in space would rapidly be a dead one, of course…), but naked eye visibility of the pyramids themselves seem secure.

  17. I think they regularly use 800mm lenses up on ISS so they can zoom in quite a bit. I think the naked eye would have a harder time getting that much detail!

    Great photos nonetheless. ūüėÄ

  18. Keith (the first one)

    That’s a spectacular picture.

    I worry that it’ll only encourage the pyramidiots who think they were built as alien launch pads or whatever those numpties think.

  19. jest

    I too have heard people argue about whether or not you can see The Great Wall from space… I think it comes down to “see it with what?” I have been able to see it using Google Earth, if you get close enough to the ground. But I think it’s an argument similar to saying “this water is elbow-deep.” (think about it)

  20. Latimer

    On a completely different note — they should take photos all of all sorts of natural formations on Earth, to see how many “Mars Faces” appear… I’d expect there are hundreds.

  21. andyo
  22. 10.   Pierre Says:

    March 13th, 2010 at 9:37 am

    Now, what kind of camera can
    get you the kind of framing we see above? One with a large zoom.

  23. 12.   Craig Sachs Says:

    March 13th, 2010 at 10:26 am

    Not with the naked eye I think that’s taken with a 300mm lens.

    NYC skeptics

  24. Even after doing Pierre’s calculations, there’s no way to know focal length if you don’t know how the pic has been cropped, or the size of the camera’s sensor. If the pic hasn’t been resized (highly unlikely) you could give it a shot if you knew photosite density (pixel density) of the sensor.

    These seem to be taken with a regular compact camera, if I’m not mistaken though. So if that’s the case, focal length is much shorter than 300mm. I think the longest focal lengths in compacts are around 100mm for those fat small “superzooms”.

  25. andyo

    Oops, my bad, just nerd over-analyzing. Noguchi was kind enough to preserve EXIF. I wouldn’t have thought Twitter also preserved it. Nikon D2X and 800mm lens, apparently. Time to get a D3x, those pics are a bit too noisy, hence I thought it was a compact.

  26. JenniferBurdoo

    In the cases of large structures, it’s possible to see shadows that are considerable larger than the items making them, at the right time of day.

  27. Surely NASA wouldn’t let astronauts zoom around looking at things with their naked eyes? This is Amurica, darnit! How dare we pollute space with our nakedness!

    (With a “desperately trying too hard” nod to the Voyager spacecraft plaque.)

  28. Oli

    Actually, isn’t every human-made object visible from space? It just depends on the zoom…

  29. Alex

    People who think that the great wall is something special in terms of being visible really haven’t thought about it much. Sure it’s very long, however it’s also very narrow, about 5m over most of it.

    What other structures do we have which are about the same width, and stretch over long distances? Roads! The standard for the US highway system is that each lane is 12 feet wide, so virtually every road is at least 7 meters wide, and most being 15 meters or more wide. If you drive south from the Canadian border on the I-29 and keep on going South, you’ll eventually end up in Kansas City. That’s about 1200 km, and long portions of that are through isolated countryside.

    Why would we be able to see the Great Wall, and not be able to see the I-29?

  30. You folks need to stop overthinking this. The myth states that the Great Wall is the only human-made object visible from the moon with the naked eye. Period.

    And clearly that myth is busted.

    I would have to guess that the only human-made thing theoretically visible to the naked eye from that distance would be city lights on the dark side of the Earth…and even that would require special conditions (a minimally-thin crescent Earth with the sun still below the horizon).

  31. Pierre

    Eric @27, I can think of another better(?) condition: being on the
    moon during a lunar eclipse. With a bit of luck, despite the bright ring
    around the earth caused by the atmosphere, maybe it would
    be possible to see the lights of a large metro area.

  32. Kilioopu

    In [Peter Hessler, Letter from China, ‚ÄúWalking the Wall,‚ÄĚ The New Yorker, May 21, 2007, p. 58] it is pointed out that the Great Wall itself is somewhat of a myth. There are, of course, northern fortifications that were built in several dynasties. But, according to this article, the Great Wall as a distinct entity is a later creation. In fact, it’s not well studied or understood even now, and there is perhaps more mythology about it (including it’s visibility from the Moon) than facts.

    If you get a chance, see the David Spindler/Jonathan Ball exhibit: “China’s Great Wall: The Forgotten Story”. It was in northern California last year, and was just in New York.

  33. I think the picture was faked. The pyramids are upside down. The point is on the top, pointing up.


    As for what you can see from space, look at Bondi Beach in Sydney, northern end, on GoogleMaps. My son’s friend, that little perve, pointed it out to me when he surveyed bathing suit optional beaches.

  34. @Keith (the first one)

    That’s silly. Everyone knows they were built as navigation markers for ancient astronauts.

  35. Mike G

    How about The World and The Palm Islands in Dubai? They’re quite a bit bigger than the pyramids and offer plenty of favorable contrast for spotting from space.

  36. There’s a dynamite animation of the Dubai area linked from this web page:

  37. Pi-needles

    Thinking Human changes to Earth that are visible from space eg. the Dutch coastline as noted by (#4.) JenniferBurdoo & (#6.) Stephen P., the near-total disappeareance of the Aral Sea in Kazakhstan / Uzbekistan ( ) and one of more of the great lakes in Africa (Lake Chad was it?) is another example of inadvertant but major alterations we’ve made to the face of this planet.

    To get a whole inland sea to shrink down to next to nothing by taking the water out of the rivers that feed it to grow cotton is pretty significant albeit not in a good way.

    Plus also on a sad note dare I add, the disappearing / retreating glaciers and diminishing extent of polar sea ice caused by human-induced Global Warming? :-(

  38. Pi-needles

    @ 32. Mike G Says:

    How about The World and The Palm Islands in Dubai? They’re quite a bit bigger than the pyramids and offer plenty of favorable contrast for spotting from space.

    Actually there are quite a few artificial islands that humans have created over time (& longer than you’d think) as I found checking up on that fount of all knowledge Wikipedia:

    Unfortunately a recent online news item suggest the Dubai world islands are getting washed away:

    So whether they still look like (33.) Tom Hill’s animation I’m not sure. I hope they do survive – think its a neat idea.

    Finally, one more link from ironic pictures:

    I probably shouldn’t be bad & stir the AGW pot any more but still. ūüėČ

  39. me2

    Hay!- Looky here! Last time I checked, pretty much everything can be seen from space. Even my house, thanks to Google Earth.

  40. I wonder how well the effects of the rabbit fence in Australia (on the surrounding soil) would be visible from as far out as the moon. To me it seems to be one of the few cases of human intervention which could be easily visible from that distance.

  41. Mike C.

    Thanks for posting the cool photo. As for Earth orbiters being able to see the the Great Wall of China, isn’t that actually a myth?

  42. It’s telling that this picture of the Pyramids shows clearly, unambiguously man-made pyramids, and looks nothing at all like Hoagland’s so called “Pyramid” on Mars. Yet, that won’t stop him drawing all sorts of squiggly lines on decades old footage to show a correlation between the two.

  43. Joey Joe Joe

    The thing I love most about this thread is not the lovely picture, but all the people nerding out trying to work out the zoom and focal length of the camera.

  44. brian

    I don’t think the camera is the reason for the noise. I think the noise is due to the poor lighting and fast movement of iss relative to the pyramids, forcing the photographer to use a higher iso and short shutter speed. The camera really doesn’t make much of a difference.

  45. TojoNeverMadeItToDarwin

    #30 @Freespeaker
    If satellites can take photos of that resolution, they don’t make it available to google.
    AFIK the Sydney shots were done from planes.

  46. @44 I am sooooo disappointed. Great beach. My son’s like the bathing suit optional part.

  47. terry12

    Looks like the pyramids have blocked wind erosion coming from the direction of the town, no?

  48. Robert Carnegie

    From the ground you can see Messier 31, the Andromeda Galaxy.

    I can’t, but I’m told it’s there.

  49. Bryan

    Yeah, a lot of man-made objects are visible from orbit if you’re allowing optics, down to surprisingly small sizes for the really advanced satellites. The Great Wall is very long but not wide enough to see unaided, unless you happen to be a falcon.


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