1. Mick West

    Mick West Administrator Staff Member

    [​IMG]

    This month NASA released a new photo of the Earth from space, taken from the DSCOVER satellite, 930,000 miles above the Earth. Some people have claimed that this new image shows an increasingly hazy Earth, and that this is evidence of an increase in pollution, or a secret geoengineering program (using "chemtrails"). Some more extreme theorist have suggested that the image is fake because the continents (particularly North America) appear to be a different size to earlier photos.

    The misconception comes from a misunderstanding about how the photos are taken. This new 2015 image is noteworthy because it's the first time since 1972 that a good quality single image photograph has been taken of the Earth. The previous last image (in 1972) was taken by an astronaut from on board the Apollo 17 spacecraft during the last manned mission to the Moon. This was the first image called the "Blue Marble", although there had been similar images taken before (such as the 1967 images taken by the ATS3 satellite), the 1972 Blue Marble image became iconic, and remains the last such image taken by an actual person.

    But notice the 1972 image itself is rather hazy, especially when compared to the 2002 image, and the 1967 image seems less hazy too. Did the air alternate between clear and hazy in 1967, 1972, 2002, and 2015?

    No, the difference comes down to the way the photos were taken, and what was done to them after they were taken. In particular, the bright blue 2002 image is not a photo at all. It's a composite image made of many individual photos taken by a very low orbit satellite (Terra). The images were stitched together in three dimensions, and then various projected images were generated by computer - in much the same way that Google Earth creates images of the globe from multiple satellite images. A similar image was created in 2012 with the NPP Suomi satellite.

    [​IMG]
    source: http://www.nasa.gov/topics/earth/features/viirs-globe-east.html

    The 1967 image is a single photograph, but taken by a very unusual camera. The ATS-3 satellite was essentially a kind of color scanner in space. It did not take photos as such, but instead "scanned" a single line across the Earth every time the satellite rotated, and then scanned another line on the next rotation, continuing for 2400 scan lines to create a complete image of the Earth. The color sensitivity was dependent on the photomultipliers, and as you can see resulted in very dark contrast, with the oceans seeming almost black.

    The 1972 image was taken on a traditional film camera, and provides a more realistic look at the Earth. The contrast though is still very dependent on the type of film used, and possibly was slighly affected by being taken through a window.

    The 2002 image, as noted already, is a composite image made of several images taken with the digital camera on the Terra satellite. It's designed to look pretty. Part of this comes from the camera itself, but the contrast and color saturation has been deliberately adjusted to give the oceans an deep blue look. We can actually recreate the 2015 image with Terra images from the same day using Google Earth.
    [​IMG]

    Notice this Terra recreation is higher contrast and more sturated than the DSCOVR image, even though it's essentially of the exact same scene (but taken over several hours, rather than all at once). It's also not as saturated as the 2002 composite image, which was adjusted for aesthetic reasons. The black "slashes" are there because the orbit does not cover 100% in 24 hours, which is why the composite "blue marble" is made from two of three days worth of images, so every single spot can be covered. Even more days are used to create an image free of clouds.

    So why is the 2015 image slightly hazier than the 1972 images? Basically for the same reason the other images are different - they were taken with different cameras. The 1972 image was taken with a film camera, and then years later scanned into digital format. The 2015 DSCOVR image is essentially just the raw digital image taken with the on-board digital camera. As NASA explains:
    The contrast color saturation is something you can arbitrarily pick after the raw image is created. Most consumer cameras boost this to make the images look better, but the more washed out image is the more realistic. Here, for example, I've adjusted the contrast and saturation of the 2015 DSCOVR image:
    [​IMG]
    It's the same image, just adjusted to be more pleasing to the eye, in a similar way to what was done with the 2002 images.

    Different cameras take different images, which will vary in color and contrast. For example, here's there photos of the same scene with the same lighting, taken with three different cameras:
    [​IMG]
    Each image is unaltered, with just three default camera settings ("P" mode on the two Canon cameras). The histogram in the corner of each image shows the brightness distribution across the image. Notice the S110 has the most saturated colors with dark yellows and reds, but the iPhone has the deeper contrast in the blues and greens. The Canon 7D seems almost washed out by comparison, but it's actually the most accurate of the three. A photographer can take this, and adjust it any way they like afterward.

    So given the vast difference between the camera systems of the 1967, 1972, 2002 and 2015 images, there's simply no way to make any kind of direct comparison between them. This is especially true when we don't know what post processing has been done to the image - here's a variety of post-processing applied to four different images. It totally changes which year seems "cleaner" or more "hazy". But really the Earth has not visibly changed.
    [​IMG]

    But what of the more unusual suggestion that the images are fake, because they show the continents being different sizes. Like many such things, it's all about perspective, and the way our brains work. We look at these images of the Earth, and our brain thinks of it as a flat object. You'd think if you get close to something, then it will get bigger, but not change shape. But this breaks down for three dimensional objects. If you get close to a globe, then you can see less of it, so the visible objects seem a lot bigger relative to the visible disc of the globe. The part of the globe in the middle is also a lot closer to your eye (relative to the edges) so seems bigger, like it's bulging out more than it actually is. You can verify this yourself with a household globe and your eyes (or a camera)
    [​IMG]
    When the camera is just a few inches from the globe, then North America seems to take up nearly all of the hemisphere. But as the camera moves back, then you can see more of the globe, and so the true relative size can be seen.

    near-far-perspective.

    This explains why South America in the 1967 image (taken 22,000 miles away) looks bigger than South America in the 2015 image (taken 930,000 miles away). But what about the 2002 image? And what about this?
    [​IMG]

    That's "Blue Marble 2012", another composite image, but this time made with the Suomi NPP satellite. Is the difference here because the Suomi satellite at a lower height compared to the Terra satellite from the 2002 images? No, the Suomi satellite at 517 miles, it actually higher than Terra, at 438 miles. And from either of those altitudes, you'd only be able to see a relatively small part of the Earth.

    Remember, the composite images are not real photos, they are stitched together into 3D models, and then images are rendered in the computer. So where is the camera relative to the Earth? It's anywhere you want it to be. Since it's a virtual camera, you can position it anywhere you want, at any altitude, and then draw the view from there. For the 2012 image, they simply moved the virtual camera to a relatively low viewpoint, and then had the computer render the view from there. You can duplicate the exact same effect in Google Earth by zooming out to about 5000 miles eye altitude.
    [​IMG]

    If we zoom out more, to the altitude of the 1972 Apollo image, we see the relative size of the continents match.
    [​IMG]
     
    Last edited: Apr 16, 2017
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  2. skephu

    skephu Senior Member

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  3. Mick West

    Mick West Administrator Staff Member

    There are also blue marble images with no clouds at all, with the oceans rendered in flat blue.
    http://sos.noaa.gov/Datasets/dataset.php?id=84

    Again, it's a 3D image made from lots of individual photos. You can view it any way you like.
    [​IMG]
     
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  4. Trailspotter

    Trailspotter Senior Member

    The apparent size of the continents depends on the distance between the camera and the Earth.
    IMG_8904.JPG IMG_8905.JPG
    The close the camera to the Earth (or, in the above photos, to a globe), the smaller area of the globe surface it captures, therefore the continents in that area look bigger.
     
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  5. Mick West

    Mick West Administrator Staff Member

    Check the OP again :) I'd already updated it with a similar explanation.
    [​IMG]
    Another good example though.
     
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  6. MikeC

    MikeC Senior Member

    The distance effect is that you are still seeing a round Earth closer up - but the horizon is further and further away from showing you a full hemisphere.

    So all the pictures show a "round" earth, and if you scale them to be the same diameter of circle then any feature on the visible portion is relatively larger the closer the shot is taken.

    I'm not awake enough to find a graphic sorry!
     
  7. Svartbjørn

    Svartbjørn Senior Member

    The only real difference I spot between the two single image photos, is that the more recent one looks dirtier. The clouds look dingy.. much like old shots of LA did back before the smog laws kicked in.

    [​IMG]

    That could just be because of the camera used to take the shot from space though, or it could be a good side by side of how badly we're polluting the atmosphere.
     
  8. Mick West

    Mick West Administrator Staff Member

    It's the camera and subsequent processing. In general atmospheric pollution has improved since the 1970s, and I don't think it's ever really been that visible from space, except in local areas, like China.

    Have a look at this comparison, where I've taken the "original" photos, and adjusted color and saturation in the opposite directions.
    [​IMG]
     
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  9. Mick West

    Mick West Administrator Staff Member

    Different cameras take different images, which will vary in color and contrast. For example, here's there photos of the same scene with the same lighting, taken with three different cameras:
    [​IMG]
    Each image is unaltered, with just three default camera settings ("P" mode on the two Canon cameras). The histogram in the corner of each image shows the brightness distribution across the image. Notice the S110 has the most saturated colors with dark yellows and reds, but the iPhone has the deeper contrast in the blues and greens. The Canon 7D seems almost washed out by comparison, but it's actually the most accurate of the three. A photographer can take this, and adjust it any way they like afterward.
     
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  10. Robert Walker

    Robert Walker New Member

    Last edited: Jul 31, 2015
  11. Mick West

    Mick West Administrator Staff Member

    They are not, but probably there's a focus on that as NASA is American. After they did the Blue Marble 2012, they released another from the other side:
    [​IMG]
    http://www.nasa.gov/topics/earth/features/viirs-globe-east.html

    I used their infographic to create this:
    [​IMG]
     
  12. Robert Walker

    Robert Walker New Member

    Ok, thanks, that makes sense. It is understandable that the images that show North America tend to circulate more and get more publicity amongst American researchers and journalists and writers of press releases :). And get more views online since a large number of the English speaking internet users are still American. It's the second country by internet use after China still, with 9.58% of the world internet users in 2014. China is top with 21.97% and India is third with 8.33% (all 2014 figures, the most recent I could find with a google search just now).

    Which would suggest that an image for English speakers that showed India at the center would also do well, get lots of shares (only 12.16% of the Indian population speak English, but probably that figure is far higher amongst those who have internet access). After that the next English speaking country by internet users is the UK with 1.95% and Nigeria with 2.3% (over 50% of Nigerians speak English, but I think you can say the UK beats Nigeria by English speaking internet user numbers because 100% speak English and we probably still have a somewhat higher level of internet access)

    Figures from: Internet live stats. Also got the over 50% just from google search of top english speaking countries.

    If you had China at center it would probably do well on pages in Chinese.
     
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  13. Trailspotter

    Trailspotter Senior Member

    Actually, this suggestion can be tested, as the other image of 2002 Blue Marble is centred on India:
    [​IMG]
     
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  14. Mick West

    Mick West Administrator Staff Member

    The composite blue marble images do not, at their core, favor any particular location (other than being centered on the prime meridian). The real products of the 2002 Blue Marble project are five equirectangular projections of the earth:
    http://earthobservatory.nasa.gov/Features/BlueMarble/BlueMarble_2002.php


    With the commonly used one being this:
    [​IMG]

    You can take any of these images and just wrap them around a 3d model, and make your own images. Attached is a Google Earth version (linking to a Low Res NASA file from BM2002)
     

    Attached Files:

  15. Mick West

    Mick West Administrator Staff Member

    A very unusual view of the Earth and Moon.

    http://www.nasa.gov/feature/goddard...nasa-camera-shows-moon-crossing-face-of-earth

     
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  16. Spectrar Ghost

    Spectrar Ghost Senior Member

    That really does look fake. I know it's the atmosphere-less moon passing in front of the earth that contributes to the too-sharp look, but it just looks badly rendered.
     
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  17. Mick West

    Mick West Administrator Staff Member

    Also the shadow and color fringe on the right makes it look like it's badly cut out.
    [​IMG]

    The fringe must be from the moon moving between the red, green, and blue fltered images.
     
  18. Trailspotter

    Trailspotter Senior Member

    Well, the cloud pattern matches that of the date, which also was the date of new moon.

    Edit: Here is for comparison computer generated images of the far side of the moon with the Earth on background at different viewing angles:
    Screen Shot 2015-08-05 at 21.43.55.
    http://www.bbc.co.uk/newsround/31302588
     
    Last edited: Aug 5, 2015
  19. deirdre

    deirdre Moderator Staff Member

    It's like HDTV where nothing looks real.
     
  20. Trailspotter

    Trailspotter Senior Member

    I like the Sun reflection in the Pacific in the centre of the Earth's disk:
    Screen Shot 2015-08-05 at 21.54.36.
     
  21. Mick West

    Mick West Administrator Staff Member

    I like that odd mask-shaped hole in the cloud layer above the moon.
    [​IMG]

    Some nice corners there.
     
  22. Leifer

    Leifer Senior Member

    There is an app, from Raytheon, demonstrating their newer VIIRS on a Sat.
    It lets you scroll around the globe, zoom, spin..... in it's three demonstrative modes.

    Desktops and phone app.

    Hard to tell if it's a refreshed view....but I think it's a one-time
    scrolled-about image, as a demonstration.
    EOSDIS Worldview can argue for and against if someone wants....
    (it's typical cloud/seasonal patterning)

    besides:
     
  23. Trailblazer

    Trailblazer Moderator Staff Member

    There is also the Himawari-8 satellite, launched by the Japan Meteorological Agency last year, which is geostationary over the western Pacific (140.7ºE). It takes high-resolution images of the full Earth every 10 minutes, and you can see them in near real time here, in zoomable form: http://himawari8.nict.go.jp/

    upload_2015-11-6_10-32-36.

    The level of zoom available is pretty remarkable.

    upload_2015-11-6_10-34-21.
     
    Last edited: Nov 6, 2015
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  24. Leifer

    Leifer Senior Member

    Last edited: Dec 7, 2015
  25. Mick West

    Mick West Administrator Staff Member

    This video has a brief discussion and illustration of the difference between the new full-disk EPIC images, and the composite MODIS images:

     
  26. Trailspotter

    Trailspotter Senior Member

    I've noticed today that the Suomi daily satellite images have been added recently to the NASA Worldview. Unlike the Terra and Aqua daily images, the adjacent Suomi swaths overlap at all latitudes leaving no gaps near the Equator:
    Screen Shot 2015-12-15 at 17.12.56.
     
    Last edited: Dec 15, 2015
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  27. Trailblazer

    Trailblazer Moderator Staff Member

    Note the mention of atmospheric aerosols and ship tracks. No doubt they will get taken out of context - "EPIC is being used to track chemtrails!"
     
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  28. David Ridlen

    David Ridlen Member

    Mr West, I am trying to locate photos that I vaguely recall you took in your yard of I think a globe and a baseball to simulate the Moon transiting Earth (?).
     
  29. Mick West

    Mick West Administrator Staff Member

    I think I just posted them on Facebook. That's the problem with Facebook debunking, it gets lost.

    20160201-131650-mtbac.

    20160402-222433-uxspw.
     
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  30. Mick West

    Mick West Administrator Staff Member

  31. David Ridlen

    David Ridlen Member

    Thanks! Your photos helped seal up another flat earth debate.
     
  32. Jonathan Evans

    Jonathan Evans New Member

    In the Video of the moon passing the earth, why does the Earth look so huge compared to images of the earth from Apollo 11, is it just from types of camera used ?? can some explain this to me before my head explodes. :p [​IMG] [​IMG]
     
  33. Mick West

    Mick West Administrator Staff Member

    It's because of the position of the cameras. The first in ON the moon. The second is a million miles away, so the moon and the earth look about their correct relative sizes.

    Imagine if instead on being taken from the moon, the first photo was taken from near an asteroid a million miles away, then (with the appropriate zoom) that's what the Earth and Moon would look like.

    20160416-112112-bkj33.

    Also explained here with a practical demonstration:

    Source: https://www.youtube.com/watch?v=M9-DMbGDsZ4
     
    Last edited: Oct 31, 2016
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  34. Henk001

    Henk001 Active Member

    Different camera position; different field of view:
    upload_2016-4-16_20-42-3.
     
  35. Jonathan Evans

    Jonathan Evans New Member

    awesome thank you guys, ive been watching flat earth videos and now almost everything that is said in those crazy videos have been debunked :) and about 4 theory's in this thread alone
     
  36. Henk001

    Henk001 Active Member

    What's left?
     
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