Quote:
Originally Posted by NETbilling
How do they actually find, analyze and photograph a planet 500 light years away?
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Spectroscope
http://www.hulu.com/watch/617730
Start at around 29 minutes... or watch the whole thing.
It's very well done. Cosmos is the best nonfiction show on television by far:
By reading the spectrum of light produced and the dark lines between each band of light they can read which elements are present. They can't see what it looks like now, they can see what it looked like 500 years ago. Add in the orbit of the planet which they can track and the size, temp of the star etc which they can also track. From that and other data they extrapolate surprisingly accurate information (as has been proven by our readings of closer objects that we have verified).