Emily, Bigfoot, and awesomeness

By Phil Plait | January 23, 2008 4:34 pm

OK, so the web traffic has slowed to firehost rates, and people can actually access this site again. So I will direct you to Emily’s blog, where — in all her awesomeness — she has posted a 3D anaglyph of the Martian Bigfoot! How cool is that?

She also makes the point that color images don’t start off that way: they are actually stacked images taken through different filters. So that means that anytime you see a color image from space, you are looking at something that isn’t moving, or else it would look all funny, blurred out in different colors. Imagine someone walking in front of you. Now take their picture using a red filter, then swap it for blue, then swap that for green… while the person continues to walk. What you’d get is a triple exposure, with three ghostly images of a person, one in red, one blue, and one green.

I mentioned Bigfoot was patient. But c’mon!

Anyway, check out Emily, as you should be doing anyway, and remember how silly teh intertoobs can be.

Update: Gia told me the BBC site links back to me on this. Tally ho! And have I mentioned lately how wonderful, smart, and pretty Gia is?


Comments (31)

  1. Kevin

    I have always wondered why pictures from space are done that way. Is it that transmitting a color picture back takes a lot longer than three B & W ones using the filters?

  2. Michael Lonergan

    Thanks. I posted this “news” story on my blog. It’s gotten the most hits today.

  3. Vitis01

    Well, I can’t see out of an eye so anaglyphs are just crappy pictures to me. (Watching Cpt. Eo was like being on hallucinogens surrounded by crazy people jumping, screaming and clutching at the air for no reason.) BUT, I have gotten tremendous satisfaction (twice already today) telling people that their Martian Bigfoot is 6 cm tall and holding very… very… still.

  4. Tom

    If you have a NxM array photo detector, it makes more sense for all elements to be actively detecting a given image. So you end up with a monochrome photodetector so all the pixels can be put to work, then place various filters in front to get “colors”.

  5. Bruce

    “I’m staring through the eyes of a rover that was only supposed to survive three months, maybe six, possibly a little longer; yet it’s been four Earth years since Spirit landed, and it’s still ticking.”

    Somebody is going to quote-mine this to extract the implication that scientists don’t know as much as they think they do.

  6. Mena

    I wish that there was some sort of scale on this image! It’s also hard to tell what is going on. I’m leaning toward it being a mostly-buried rock because it seems like the sediment going toward the right side of the rocks is a lot finer. There seem to be similar things happening with the rocks to the right of Bigfoot, going (kind of) out from him along a ~120¬į line. There is a lighter rock large rock a bit out but directly to the right of it. The shadows seem to be toward the left. I’m not used to space images so I’m probably way off on this…

  7. Chip

    I find the multi-layered, slab-stepped rocks in the foreground under “Tiny Big Foot” much more interesting than “Tiny Big Foot”.

    I also like the sandy “path” leading off on the far right side of the picture.
    Formed by Martian winds? A rolling boulder? Migrating Martian Woowoobeasts? ūüėČ

  8. DarthTed

    Looking at the Sun’s pics, I noticed a second figure, lying on the ground to the right of Bigfoot. With Bigfoot’s arm outstretched, it looked like BF through second figure off the ledge. Time to call in CSI:Mars. Of course, even that is not nearly as interesting as the items found by the Fark commentors.

  9. Minutes ago, channel 4 news in Jacksonville, Florida ran a credulous story about this image. The spent about fifteen seconds on the story, and mentioned only once that the figure “may” be a rock. But they said it looked like a man, or maybe a woman, or at any rate a person with their head tilted, that the image was taken in 2004, but that the image was lost (?) until it was “found” on a Chinese website, blah, blah, blah.

    Bad Astronomy wasn’t referenced, nor was Emily, nor was any of the information they present.

    Florida: Doomed.

  10. I had posted a link to a cross-eyed stereo image and an anaglyph of “bigfoot” in the original comment thread.

  11. skylinkdave

    Don’t feel bad, blue collar. They did the exact same thing here in Denver. They never bothered to mention that the “bigfoot” in the picture is only about 2.5″ tall. I need to call the station and complain.

  12. 1) Wondered about the access problem.
    2) Came back today, and read about “Martian Bigfoot,” scratched my head about the hubbub. (Been sick, missed out on all Big Media foolery.)
    3) Clicked over to ‘Emily’ (Thanks to a previous rec from this site.)
    4) Was completely entertained and enlightened by the photos and explanations.

    Two days of controversy experienced and resolved in only ten minutes, with beautiful Mars pictures as my ultimate reward.

  13. owlbear1


    Look at all that dust on that beautiful robot!

    Poor thing.

    My kingdom for a case of canned air and a 60 million mile long extension tube!

  14. Pandora

    How fast is the shutter speed on the Rover’s camera? If it were fast enough then the ghostly images would be nearly undetectable but they would still exist. But really it is most likely a rock. I doubt it is 2.5” though, because those sand formations look too large to happen on that scale. Sand ripples at a close focus would be appear smooth and more flat because the gust of wind that created them would have hit all of the sand particles in that very small area and ,as the individual sand particles do not have the mass nor friction to resist much, moved them all in a semi uniform manner. The formation of sand waves is not incredibly well understood but you can see clearly the wear and tear of mother mars on the rocks and the patterns in the sand due to their non-aerodynamic wind resistance…you can even see a dune or two. The thing everyone is fascinated with is most definitely just some eroded rock that happens to have very very very minute likenesses to a human. Go look in any desert and you are bound to find something similar.

  15. ArnHay

    Well after zooming in on the close-up picture I was left with the impression of a bird-like plant with a shady blob on it’s “head”. The “arm” is a different color (yellowish) than the “body” (greenish). From there my impression of a birdlike something, because it looks a bit like some kind of bill.

    Also just a bit to the right of the top of the vertical column like bit of the rover in the picture there is a strange rock that is slanted at a weird angle. Funny enough this looked a lot to me like one of the wyrms of Dune. Bleh… Anyway. It does not look like a rock. It’s texture is completely different than the rest of the rocks on the picture. More knobbly whereas the other rocks have clearly been eroded by wind.

  16. Hugo

    The Australian news media are reporting on this now. The mainstream media too (Channel 9, which is about as mainstream as you can get down here for pure ‘infotainment’).

    I couldn’t help but notice in the planetary.org photo, down the bottom near the rover there’s what appears to be a squirrel chasing a guitar. Yes, you heard correctly.

    It’s a MARTIAN squirrel chasing a MARTIAN guitar. On MARS. Quick, someone get Hoagland! There’s are squirrels on Mars! Chasing guitars, I tell you!

  17. vmos

    So it’s only 6cm tall and doesn’t move?

    I know, it’s a martian leprechaun! a martian leprechaun that’s been turned into stone by the matian medusa!


  18. Doug W

    # blue collar scientiston 23 Jan 2008 at 8:45 pm

    Minutes ago, channel 4 news in Jacksonville, Florida ran a credulous story about this image…..Bad Astronomy wasn‚Äôt referenced, nor was Emily, nor was any of the information they present.

    Why would they be mentioned, Blue? Ain’t their picture and Bad Astronomy’s opinions on the NASA picture are worth no more and no less than anyone elses.

  19. re:Pandora…

    The actual exposure time for every pancam frame is found in the PDS header of the calibrated data product that is released in 3 months chunks, 6 months down the line. I found a typical Pancam exposure from the PDS here : http://anserver1.eprsl.wustl.edu/navigator/productPage.aspx?prodId=2P133384688EFF2232P2582L2C1&prodClass=science&prodView=label : and the exposure is described as

    So basically, 1/4 of a second.

    However – that’s not the time issue that Emily was refering to. Every image Pancam takes is black and white. The colour images are built from three black and white images. One taken thru a red filter, one thru blue, one thru green ( typically near IR, green and blue actually )

    http://marswatch.astro.cornell.edu/pancam_instrument/images/integ3.jpg shows the filter wheel that does this.

    It takes a few seconds to take a picture, download it to the rover’s computer, turn the filter wheel, and then take another picture. Something like 20 to 30 seconds – that sort of range. What Emily was suggesting wasn’t that our little basalt yeti would visibly move in the 1/4 second exposure, but that it would visibly move between the taking of the red and green, and the green and blue images.

    Things DO move on Mars and exhibit this artifact of filtered imaging. Firstly, dust devils
    or http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20051107a/Everest_L257atc-A622R1_br2.jpg

    You can see, with the full resolution of that panorama, a wierd green fuzzy patch and a red fuzzy patch – off near the horizon, right of centre. That’s a dust devil moving between filters.

    http://pancam.astro.cornell.edu/pancam_instrument/335B_heatshield.html is another example – the little glare reflections from the foil of the heatshield have moved around – you can see a little red, blue and green glare marks that are in different places, because the sun has moved slightly, and the foil has blown a little in the wind.

    One thing to note is that when they take stereo images ( i.e. the left and right eye together ) those images are actually taken at the very same time. But colour images are typically all done with the left camera and you need to wait between filters to take the images.

    So, unless our granite friend stood stood perfectly still for 82 seconds – we would have seen three seperate little strolling Yeti’s in the different filters. And, given that we also have a lower resolution image from 3 days before – that shows it in the same position – it’s fair to say that this is a ‘static’ object. We’ve seen hundreds if not thousands of odd shaped rocks with the rovers. But then, we’ve all seen odd shaped rocks with our own eyes – the cliffs that look like faces, the pebble that looks like a button, the chunk of flint that looks like a bone etc etc. That, from the hundreds of thousands of rocks observers on mars, one looks a bit like a strolling yeti, is far from exceptional.


  20. Forgot to mention the size issue. Finding out the size of something from Pancam images isn’t THAT hard. It’s trigonometry basically. The two cameras are a known distance apart, and are pointing at known angles. If you identify the location of the feature in both frames, you can use the different in location to establish a triangle which has a base between the two cameras, and the other sides from the cameras to the object. Calulating the ‘height’ of that triangle is just maths.

    Once you know how far away it is ( 4.7m +/- a few cm ) then you can use that information along with the angular resolution of the object to calculate another triangle – one with a base that is the dimension of the object, and peak is at the camera. You know the angle, you know the height of the triangle, so calculating the base is again, just maths. In this case, 5.7cm (+/- a few mm ) It’s very very reliable and suprisingly accurate. Put a credit card on opposite side of a reasonable sized room, and that’s the sort of size and distance we’re talking about.


  21. know nothing about mars

    Just to add to Bruce’s comment on Rover. The reason Rover is still on Mars is cos the BF keeps fixing it. Every time it gets stuck BF is there to push and clean its solar panels. This picture proves what I just said and shows the BF enjoying the view. In a few months he’ll be back in Himalayas and rover will stop working. Watch this space for more updates!!

  22. john

    One thing that seems to be missing from the commentary that points to the image at http://www.nasa.gov/images/content/207495main_Spirit.jpg is a pointer as to where the small image is in the larger picture.
    I tried looking for places that seemed to be about 5 meters from the rover with appropriate rocks and background, but I must be pareidolia-challenged. (I suppose that means that I can’t face it)
    Anyone have directions for someone lost on Mars?

  23. Chris P

    A friend called me this morning saying she had seen a report on the local news about plant life possibly found on Mars!!

    Btw, I don’t know if it’s the squirrel chasing the guitar, but I found what is clearly a Martian hedgehog. In fact, as I stared at the full-res image I began to see tiny men in many of the shadows. The bigfoot figure is just above the large rocks at the far lower left.

  24. Mark Martin


    The anthropomorph is way over around the lower-left corner, on the edge of a rise in the foreground, and it is TINY.

  25. karlos

    this G.W.Bush on Mars!!!!

  26. McMurdo

    “We‚Äôve seen hundreds if not thousands of odd shaped rocks with the rovers. But then, we‚Äôve all seen odd shaped rocks with our own eyes – the cliffs that look like faces, the pebble that looks like a button, the chunk of flint that looks like a bone etc etc. That, from the hundreds of thousands of rocks observers on mars, one looks a bit like a strolling yeti, is far from exceptional.”

    So Mr Doug it’s easy to mistake a sculpture for a natural shaped rock. Well…how can you be so sure which is the case???

  27. HAQ

    I am glad to read Emily’s use of ‘enlarge’ rather than ’embiggen’ which simply annoys me to no end. Surely the BA’s mean streak has some give to it?

    How’s about LOLCats dump some ripe kittylitter down your scope? Along with the other resi-‘dews’?

    I mean — really!



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