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Earth and Moon From an Alien's Perspective
krygny writes "NASA's Deep Impact spacecraft (whose extended mission is called EPOXI) has created a video of the moon transiting Earth as seen from 31 million miles away. Scientists are using the video to develop techniques to study alien worlds. 'Our video shows some specific features that are important for observations of Earth-like planets orbiting other stars,' said Drake Deming of NASA's Goddard Space Flight Center... 'A "sun glint'" can be seen in the movie, caused by light reflected from Earth's oceans, and similar glints to be observed from extrasolar planets could indicate alien oceans. Also, we used infrared light instead of the normal red light to make the color composite images, and that makes the land masses much more visible.'" Here are links to the two videos, one red-green-blue and the other infrared-green-blue.
Perhaps I am, but 31,000,000 miles doesn't seem that far away from an astronomical perspective - in fact it seems pretty darn close. A single light-year is about 5,878,625,373,183.61 miles (from Wiki), so 31M miles is roughly 1/190,000 of a light year.
The nearest star is ~4.2 light years away, so our potential alien visitor would have to travel a very long way towards us (and in that case why not come the last 0.0001% of the journey!) before this was a useful property.
Now I realise you can only take a video from as far away as your spacecraft really is, but I'd expect to see extrapolations to realistic distances before you start to claim things like "Making a video of Earth from so far away helps the search for other life-bearing planets in the Universe". - that's a bold claim, after all. I'm sure there's a standard line somewhere about extraordinary claims requiring extraordinary evidence to back them up...
I dunno, perhaps I'm just a grumpy old physicist, but there's all sorts of effects that only come into play at astonomical-scale distances (and the relativistic-scale speeds that commonly occurs between bodies that far apart), I guess I'd like to have seen more data and less hand-waving.
Simon.
Physicists get Hadrons!
wow... that was cool
I was going to post the usual attempt at witty snarkiness, but then I actually watched the video... seeing the Moon actually moving around the Earth like that, it actually made my heart skip a beat. Seeing us that way with my own eyes someday, as unlikely as it may be, is something I really long for.
http://twitter.com/OLDTELEGRAM
Actually, no, I don't. I think if Sagan was miraculously reconstituted today, he would take one look at the shape of our Education System and of the Sciences and Space Program in the States and he would die of shock and sadness.
Edward@Tomato - /home/Edward/ man woman
man: no entry for woman in the manual.
"Qua!?"
A video like that really helps you realize how small and insignificant you really are.
On the contrary, if you accept what the Fermi Paradox implies, it shows how unbelievably special, improbable and unique we are in the entire galaxy, if not the entire Universe. [personally, I suspect intelligent life is so improbable that it takes 2.55e35 cycles of the universe(s) for it to happen, on the average.]
Sometimes it's best to just let stupid people be stupid.
Facts have no bearing on these kinds of opinions. There are people for whom things are always worse, as current situations are constantly compared to an idealized past that never actually existed.
Such people get joy out of believing that they are the last of some special breed of amazing people, never to be seen again. It's just part of the human condition.
It deserves pity, but not recognition or respect.
Yup, but to me (and damn near 100% of everyone else), you're really close to nothing. Outside of this planet, you're even closer to nothing.
Hence, insignificance.
Holy cow, it's Uwe Boll imitating Buckaroo Banzai. That explains everything.
The problem with the film isn't the ridiculous number of creative liberties taken with physics. It's the fact that of all the highly qualified, professional people who would undoubtedly volunteer in droves to save the world, the crew is made up of a bunch of unstable, narcissistic emo whiners, and the ship is designed in such a way to give them endless opportunities to fail. It's a slow horror movie, and like all bad horror movies, the suspense is driven by the stupidity of the characters.