Ned Potter is the science correspondent for ABC's "World News with Charles Gibson." He has reported on such topics as space exploration, the human genome and climate change.
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Transit of Earth
July 18, 2008 12:41 PM
31 million miles from Earth, NASA's Deep Impact spacecraft has taken a look back at us -- at just the right moment. In a time-lapse movie from May 29, it shows a transit -- a passage of the Moon across the face of the Earth. We think you'll agree it's very cool.
There's more information HERE from the University of Maryland, which runs the mission for NASA. (NOTE, added Saturday: you can also find different formats there of the video, without the commercial that plays with our embedded version. My apologies to those who were annoyed by it.)
The darkness and slightly ruddy color of the Moon are not accidental. We think of the Moon as a bright disc as it reflects sunlight our way, but in fact lunar soil is much darker than the Earth, with its white clouds and blue oceans. Apollo astronauts, describing the Moon's color from close-up, often remarked about the...lack of color.
The movie is very sped-up; it was assembled from images shot fifteen minutes apart. More information HERE.
Deep Impact made its mark on July 4, 2005, when it sent a probe crashing into a comet and recorded the results. Even NASA believes in recycling these days: the robot ship has been given a new mission, called EPOXI; it will fly by another comet in 2010.
The University of Maryland says the video is for more than amusement. Images from the last six months of flight will be used "to characterize the Earth as a planet for comparison with planets around other stars."
Video Credit: Donald J. Lindler, Sigma Space Corporation and NASA/JPL-Caltech/GSFC/UMD
July 18, 2008 | Permalink | Share | User Comments (43)
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It just does not get any COOLER than this! NASA is worth every penny of my tax dollars. Unlike a certain war that never should have been started. These images are honestly, what makes life interesting & exciting. THANK YOU NASA!!!
Posted by: PhillyPaul | Jul 18, 2008 1:33:39 PM
Almost forgot! THANKS to you too Ned!
Posted by: PhillyPaul | Jul 18, 2008 1:34:39 PM
How incredibly pretty. You know the moon is moving away from us? How many more years will we be able to live on this lovely little planet... ?
Posted by: yolande | Jul 18, 2008 1:38:49 PM
yolande,
I think I read somewhere that the sun will become a red giant long before the moon leaves Earth orbit.
Posted by: Bob | Jul 18, 2008 1:48:24 PM
Is this from last night or from May? Does anyone know?
Posted by: Chris | Jul 18, 2008 1:55:03 PM
And people say there is "no" God
Posted by: Lifesource | Jul 18, 2008 2:21:23 PM
Awesome. Simply awesome.
Posted by: Soldier | Jul 18, 2008 2:29:38 PM
WOW, THIS JUST PROVES THAT GOD MAKES THE BEST PICTURES!!!!!
Posted by: RICK | Jul 18, 2008 2:31:51 PM
Very cool movies. Just wish the resolution was better.
Posted by: Larry | Jul 18, 2008 2:35:47 PM
There is NO God, probably.
Posted by: edward | Jul 18, 2008 2:42:37 PM
Very cool indeed. I don't see how it
"proves" there is a god though..
Posted by: Sean | Jul 18, 2008 2:43:26 PM
Note from Ned Potter--
Larry, we asked about the video quality. The answer from NASA's Goddard Space Flight Center is that the time-lapse was put together from a very small part of each image sent by the spacecraft, so they can't improve it. (Think of enlarging one face from a group photo you take with a digital camera.)
"That's what you get from 31 million miles away," said one of the people we reached.
And, Chris, just to clarify: the images are indeed from May 29, just released. They said it took a little time to realize they had something good, and then match up the images to turn them into a time-lapse.
Posted by: Ned Potter | Jul 18, 2008 2:46:17 PM
Cool! :)
I find something odd though. Does the moon orbit around the Earth that fast? In the vid, the Earth didn't even complete one rotation on its axis before the moon came zipping by.
Posted by: GWP | Jul 18, 2008 2:51:56 PM
Fool Most of the people some of the time. Fool me non of the time. NASA The Truth is comming out and there is nothing you can do about it.
Posted by: Corrice | Jul 18, 2008 2:53:59 PM
Amazing video, question, why does the earth seem to take a shift to the left as the moon passes from the shadows into the sunlight? Gravity from the passing moon shift the camera? Does gravity bend the light, manipulating our view? Simple camera quirk?
Posted by: Amazed | Jul 18, 2008 3:02:39 PM
And then Corrice checks in from the grassy knoll.
Posted by: Zinglesloff | Jul 18, 2008 3:09:18 PM
GWP, the movie is a combination of 97 frames taken over 24 hours. It appears that the moon is moving quickly, but we are only seeing a very, very small part of the orbit that crosses in front of the Earth.
Elizabeth
Posted by: Elizabeth | Jul 18, 2008 3:21:45 PM
I had never before considered how much higher is Earth' albedo compared to that of the moon. Next to "Earthlight", moonlight looks really dingy and dim! BTW, one reason that Earth might appear to shift to the left in this time-lapse is simply that Earth DOES shift a bit. The moon does not revolve around Earth's center, but rather Earth and its moon revolve together in a dance around their common center of mass ("center of gravity" or "barycenter") in such a manner that that common center of mass DOES NOT shift in its orbit of the sun. When the moon goes one way, Earth must simultaneously shift the other way by perhaps several hundred miles, so that the common center of mass may remain in its place or path.
Posted by: Jordan | Jul 18, 2008 3:27:04 PM
Jordan,
That shift would not be noticeable. I don't see the shift that is being described, but I imagine that it could be simply in the playback or in the interpretation of the jerkiness from doing frames every 15 minutes rather than every minute or every second.
Posted by: Elizabeth | Jul 18, 2008 3:39:54 PM
GWP, in addition to what Elizabeth said, remember that the Earth-Moon distance is several dozen Earth radii. So the Moon is travelling in a much larger circle than is immediately apparent in the video.
Posted by: Kacky Snorgle | Jul 18, 2008 3:50:43 PM
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