Would we detect night-side lights on an exoplanet?

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Offline thedoc

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Chris Miller  asked the Naked Scientists:
Chris Miller from Clifton Forge Virginia USA here.

I have a question for the Naked Astronomers.

Since our scientists gather much of their data about exo-planets by studying light, would exo-scientists notice the amount of light coming from the Earth's night sky produced by man-madelighting and be able to infer that there is life here? In other words, if scientists found a planet whose dark side was less dark then it should becould that be a sign of life?

Thank you all for all your podcasts.


What do you think?
« Last Edit: 14/06/2012 11:30:01 by _system »


Offline Phractality

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Re: Would we detect night-side lights on an exoplanet?
« Reply #1 on: 14/06/2012 18:48:34 »
Our telescopes would need to resolve many times better to actually see exoplanets, though we have been able to finagle images from the data to show a large exoplanet as a speck of light near its star. The light from the star is billions or trillions of times brighter than the light reflected by any planet, so we must somehow eclipse the star with an intervening object (like a companion satellite near HST). Even then, light refracted around the edges of the eclipsing object will obscure any planet; that light must be subtracted digitally to reveal the light reflected by the planet.
Once we overcome those problems well enough to image a crescent planet, we'll still be many orders of magnitude short of revealing anything like the artificial lights that we can see in images of the night side of Earth. In the near future, I expect we might be able to detect an H-bomb exploding on the dark side of an exoplanet; that's about the best we could hope for.
Imagination is more important than knowledge. Einstein