![BlueMarble80](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="80" height="80"><rect fill-opacity="0"/></svg> "BlueMarble80")
One of the default pictures included with the iPhone is a beautiful image of the Earth as seen from space. Unless you weren't paying attention, you saw this picture when you first purchased your iPhone, and you can still view it by going to Settings --> Wallpaper --> Wallpaper; it is the second image provided by Apple. Here is what it looks like as a wallpaper on an iPhone:
![IMG_2307](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="320" height="480"><rect fill-opacity="0"/></svg>)
If you have ever wondered where this photograph came from, a recent post from Gizmodo sheds some light on the subject, although to get the full story you need to go to some more sources, including this page from the Institute for Atmospheric and Climate Science in Switzerland. Here is a short version.
First, a little history. One of the most famous pictures of the Earth was taken on December 7, 1972 from a distance of about 18,000 miles out by the crew of Apollo 17 who were fortunate enough to have the sun directly behind them so that the Earth was fully illuminated. One of the astronauts, Eugene Cernan, quipped when the picture was taken: "I know we're not the first to discover this — but we'd like to confirm, from the crew of America, that the world is round." The image was called Blue Marble and is one of the most widely distributed photographs in existence:
![Apollo17_small](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="400" height="400"><rect fill-opacity="0"/></svg>)
[UPDATE 12/11/2013: You can view the original Blue Marble 1972 picture on the NASA website here, with many different versions available.]
In 2000, climatologist Reto Stöckli was working with the NASA Earth Observatory team and decided to update that famous picture. By compiling satellite data and images taken over several months, he created an artificially colored image that he also called Blue Marble:
Then in 2002, Stöckli worked with Rob Simmon of the NASA Earth Observatory and others to update that image and create a so called "true-color image" that was based on data which closely reflects the full spectrum range of visual perception. In other words, this is what the Earth might really look like if you were in space. This image, called Blue Marble 2002, was the most detailed true-color image of the entire Earth to date. To be clear, this is not a single snapshot of Earth, but instead is a composite of months of satellite-based observations. Most of the data came from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) which flew on a satellite over 400 miles above the Earth, so much closer than the 18,000 miles out of the Apollo 17 astronauts. Here is Blue Marble 2002:
You can download the full size, 2048 x 2048 pixel, version of Blue Marble 2002 from the Flickr page for the NASA Goddard Space Flight Center. You can also view this animation of the Earth spinning created from the same images. NASA released the Blue Marble 2002 image to the public, and that was the image that Apple decided to use on the iPhone.
Although the Gizmodo article cited above says that this is this is the highest resolution image of the earth, that is actually no longer true. Stöckli, Simmon and the rest of the gang got the band back together to work on a project called Blue Marble: Next Generation (BMNG). Using MODIS data from 2004, the BMNG team created this image in 2005:
The full size version of Blue Marble 2005 is 4096 x 4096 pixels, so it is four times the size of the 2002 image used by Apple on the iPhone. You can download full versions of all of the images mentioned above — the 1972 Apollo 17 image and the Blue Marble versions dated 2000, 2002 and 2005 — on this page from the Institute for Atmospheric and Climate Science. [UPDATE 12/11/2013: That page doesn't work anymore, but there are other links to these photos above.] You can also get more information on all of the different versions of Blue Marble on Wikipedia.
Although Blue Marble 2005 is the more recent and more detailed version, in my opinion the 2002 version is the most beautiful of all of them, although of course the original 1972 version is also wonderful because it is "real" and not a composite. I suppose that someone at Apple felt the same way since the 2002 version is the one included with the iPhone. If you changed your iPhone's default wallpaper then you probably won't see this image on your iPhone again unless you have a serious crash and the iPhone returns to a default state and commands you to connect your iPhone to a computer running iTunes. If that does happen to you and you find yourself starting to panic, perhaps you can distract yourself by thinking of all of the time and care that went into creating the beautiful image of Earth on your iPhone screen.
[UPDATE 1/26/12: NASA has now released Blue Marble 2012, an even higher definition (8000 x 8000) view of Earth created by combining several images taken by a NASA satellite on January 4, 2012. Looks like it is time for Apple to update the iPhone wallpaper!]
[UPDATE 5/23/16: In February of 2015, NASA launched the U.S. Deep Space Climate Observatory (DSCOVR) (Wikipedia link), a satellite which stays in the correct position to always see the sunlit side of the Earth. The camera on DSCOVR is called the Earth Polychromatic Imaging Camera (EPIC), and it takes a picture about once every two hours. Thus, we now have 12 new Blue Marble-style pictures of the Earth every single day. The first released set of images were taken on July 6, 2015, and you can see all of the pictures on NASA's website here. Some of them are particularly amazing, such as this series of pictures (and video) of the moon passing between EPIC and the Earth, taken July 16, 2015. It is fascinating to me that an image that originally was breathtaking in its uniqueness back in 1972 is now literally an everyday occurrence.]
The image Apple chose is the only one that centers on North America.
Nice backstory! I have a soft spot for Eugene Cernan's "true" 1972 photo, but they're all absorbing. I wonder why in the "Blue Marble 2002" image which Apple used there appears to be a darkish rectangle at about 1:00 in the area of Baffin Island?
In the last paragraph you state that the iPhone includes the "real" 1972 version and yet earlier on you say that Apple decided to use the 2002 version, so which is it? The one in the iPhone screen shot you show is clearly different to the picture below it.
[Jeff responds: Sorry if that wasn't clear. I meant that someone at Apple apparently agreed with me that the 2002 version is the most beautiful. You are correct that the 2002 version is the iPhone version, not the old 1972 version.]
What a great bit of history. It's amazing the truly amazing things we take for granted. I also agree with the first commenter Jakob that the 2002 centers on North America. Apple is very proud to be from the U.S.A. The shot is also the best composed with North America being front and center.
I'm going to go put Blue Marble 2002 back as my iPhone wallpaper and enjoy it.
[Jeff responds: Likewise, I've had the Blue Marble back as my iPhone wallpaper for the last few days while I was working on this post, and it really is a nice wallpaper.]
Maybe you can answer a question I've had about Blue Marble 2002 for a few years now -- blogged here: http://deraill.com/journal/2008/12/09/is-this-what-they-mean-by-healing-the-planet/ -- are the repeated patterns really just sloppy compositing work, or unavoidable artifacts of the sat. photography process?
[Jeff responds: I don't know the answer, but perhaps someone else does and can respond here.] [UPDATE: Ask and ye shall receive. See below comment from Kevin Purcell.]
That's the only one centered on the USA. Americans like to believe the rest of the world doesn't exist.
Am I correct in recalling that the 1972 image is noted in AN INCONVENIENT TRUTH as the most published image of Earth? I know as a less-experienced graphic designer I used it some years ago for a movie trailer. It was on a reasonably priced CD of stock space photos. I always thought it was cheap because it didn't center on N. America, but that was what I liked about it.
Like some others here. I'm switching back to the Blue Marble, too! Until I can rez some of the others to fit nicely.
I dont think you should refer to the "institute" as "Swiss Institute for Atmospheric and Climate Science", since its only a part of the "Swiss Federal Institute of Technology". I don't know if there are more institutes for atmospheric and climate science in Switzerland, but since for example referring to the Apple Tech Support simply as "The American Tech Support" would be wrong, too…
[Jeff responds: Good point. I only intended to point out that the Institute is in Switzerland. I've edited the post to make that more clear. Thanks.]
"The full size version of Blue Marble 2005 is 4096 x 4096 pixels, so it is four times the size of the 2002 image used by Apple on the iPhone."
4096 x 4096 is not four times the resolution of 2048 x 2048, it is only twice the resolution.
[Jeff responds: Is that right? I thought about that when I wrote this post. Wouldn't 2048 x 4096 be twice the size of 2048 x 2048, and thus 4096 x 4096 is four times the size? Either way, you can see the actual numbers so hopefully it is clear what I was trying to say.]
I'm not sure what "four times the resolution" means, but 4096x4096 is certainly four times the SIZE of 2048x2048.
Humphrey: (4096 * 4096) / (2048 * 2048) = 4. The dimensions are doubled, but the area, which is squared, quadruples.
The full resolution of Blue Marble Next Generation is 3 panels each of 21600x21600 pixels. You can download them all from here http://visibleearth.nasa.gov/view_detail.php?id=7106
"The image Apple chose is the only one that centers on North America."
Not really true. If you browse around the photosets you will find the other versions of the blue marble. I found one centered on India.
http://www.flickr.com/photos/gsfc/4392965590/in/photostream/
Actually -- NASA has a 43200x21600 version available somewhere!
very cool history on this photo. I agree - the 2002 version is amazing. And thanks for the link to the full size pic! Nice.
@Thecreative [Jeff adds: Actually the question was from Ben; it is a little confusing how TypePad identifies the person BELOW the comment] asks about the odd "clone tool" like artifacts seen in the cloud patterns in the MODIS derived Blue Marble images.
The underlying issue is it's a composite taken over time rather than a single photograph.
These arise because the image is generated from a low earth orbit satellite in a polar orbit (Terra for the MODIS capture images). Traveling roughly north to south twice a day captures strips of land and sea. These then need to be composited together to make a "whole planet" composite.
The problem is the weather systems in these strips keep moving so you do one strip then 90 minutes later you do the next strip and so on around the planet and the clouds don't line up from strip to strip giving he cloning effect.
If you want the whole planet to be in daylight too (i.e. you don't want a terminator in the image) then you are going to select strips from different times exacerbating the effect.
Though the Apollo 17 shot is popular the more important photo is the Apollo 8 Earthrise photographs taken in 1968. I use the first of the Earthrise shots (the black and white one before they switched to a color camera) in the correct orientation) on my blog.
Jeff here. I asked Kevin Purcell to tell us a little bit more about the Apollo 8 shot on Kevin's website -- http://kevin-purcell.blogspot.com/ -- and here is what he told me an e-mail:
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The orientation I describe [in the Apollo 8 image on Kevin's website] is as the astronauts saw it through the window facing towards to the moon. The CM was in an equatorial orbit above the moon so the moon is off to the right and the earth appeared to "rise" from right to left. The CM just rolled to look at the lunar surface just before the earth came up and then one of them spotted the earthrise.
On earth sunrises happen with the horizon horizontal so all the reproduction you see are rotated by 90 degrees to make it "seem right". In space it doesn't matter. Of course this could be done by rolling the CM 90 degrees counterclockwise but then the window wouldn't point in the right direction to see the earthrise.
But the official framing from the NASA originals is as shown in the cropped image on my blog: moon on the right with it's "horizon" vertical.
Check out the original images
as08-14-2329 -- the black and white first shot
http://history.nasa.gov/ap08fj/photos/e/as08-13-2329.jpg
as08-14-2383 -- the classic color shot
http://history.nasa.gov/ap08fj/photos/b/as08-14-2383.jpg
as08-14-2384 -- the second color shot
http://history.nasa.gov/ap08fj/photos/b/as08-14-2384.jpg
Wikipedia also comments on the orientation of the photograph:
http://en.wikipedia.org/wiki/Earthrise
And to go back to your original topic the original orientation of the Blue Marble photo (AS17-148-22727) has been flipped too with south at the top in the original shot.
http://spaceflight.nasa.gov/gallery/images/apollo/apollo17/html/as17-148-22727.html
http://en.wikipedia.org/wiki/The_Blue_Marble
It's worth listening to the audio and reading the transcript (starting at 075:46:27) as they shot the Earthrise photos. The transcript is also glossed with comments about the photographs orientation.
http://history.nasa.gov/ap08fj/14day4_orbits456.htm
http://history.nasa.gov/ap08fj/audio/earthrise-nr.mp3
> 075:47:30 Borman or Anders (onboard): Oh, my God! Look at that
> picture over there! Here's the Earth coming up. Wow, is that pretty!
> 075:47:37 Anders or Borman (onboard): Hey, don't take that, it's not
> scheduled. (Chuckle.)
Though it's a joke, it's interesting no one thought to schedule a photo of the earth from the moon. It just never crossed anyone's mind. It's still disputed who took the shots.
I still think these two photos are the single two best shots to come out of the manned space program.
And to go over the top their significance reminds me of the lines from T.S. Eliot's "Four Quartets":
We shall not cease from exploration
And the end of all our exploring
Will be to arrive where we started
And know the place for the first time.
That's the real significance of the Earthrise photo and it's impact on the environmental movement. The Blue Marble just reinforced that.
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And again, just to be clear, the above all comes from Kevin Purcell: http://kevin-purcell.blogspot.com/
@Kevin Purcell, thanks for explanation. I had always assumed the composite was from more disparate sources, over a greater period of time, and the weather was touched-up. Fascinating.
The original is always the best. A beautiful snapshot from a 70s camera. Simply awesome.