io9
At the Astrobiology Science Conference 2008 Nick Wolfe of the University of Arizona said yesterday that the best way to tell whether an exoplanet may harbor water — and life — is for us to launch a mission into space that will look back at Earth. Ever since Voyager I launched we've had a chance to gaze from afar at the homeworld, but for some reason we've passed up the chance. Wolfe said that's a critical oversight. As we search for new planets that might harbor life around far-off stars, it might be useful to know about what our own planet looks like from a distance.
The Earthrise photo (and check out the video if you really want to feel tiny) taken from Apollo 8 is one of the most famous space pics ever taken. Along with a few other nearly identical images, the shots are the only space-borne perspective that feature our pale blue dot from anything like a wide-angle view. This sort of thing is exactly what we need more of, Wolfe said. Imaging all of the phases of Earth (crescent, half, gibbous, full, etc.) from at least one lunar distance away would give us tons of info for what a world with continents, a dynamic atmosphere and water looks like.
The grand prize would be taking an image of the Sun's reflection on our oceans in polarized light. "That would give us a measurement of what the glint of sunlight on water looks like," Wolfe said, which could be used to determine whether planets are other stars have liquid water on their surfaces too.
Image: NASA
Comments
Take a look at the lawman
Beating up the wrong guy.
Oh man!
Wonder if he'll ever know
He's in the best selling show.
Is there life on Mars?
Actually, the Japanese Moon Probe just recently took some really great Earth Rise shots: [www.msnbc.msn.com]
Would it make sense to include a special sensor package on the next probe to the outer planets to do this comparison check Wolfe suggests. It could be calibrated to perceive Earth as if it a lot further away, in other words make it "myopic". If I look across the street without my glasses the quality of what I see is what someone with 20/20 vision sees at twice that distance. Obviously I'm not an engineer but this might work.
It's a great idea, as a way to have baseline comparisons. Why has no one ever thought of this before?
You're missing the famous "Pale Blue Dot" photo, taken from Voyager 1 at a distance of 4 billion miles. [en.wikipedia.org]
Along with a few other nearly identical images, the shots are the only space-borne perspective that feature our pale blue dot from anything like a wide-angle view.
There have been plenty of observations of the Earth made by spacecraft with a "wide-angle view". It's quite common for probes heading for other planets (or asteroids or comets) to pass by the Earth once or twice for gravity boosts, and they often turn on their instruments during the flyby.
Some of the more spectacular examples:
Movies of the Earth and Moon rotating during the Galileo fl... (1990)
(Which produced a paper in Nature by Carl Sagan and others discussing which signatures of life were visible during the flyby.)
Images and movies taken by the Mercury-bound probe Messenger (2005)
Images of the Earth and Moon taken by the comet probe Rosetta (2007)
@Gyrus: I would think that it will take more than just a camera shot from a distance. It will take a similar sort of instruments on the probe, that we use here, so it would seem we would need to start from scratch, and then wait forever to gain the necessary distance. Possibly a computer simulation would be a good alternative while preparing the mission.
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