[thedoc (OP)]

Astronomers have found compelling evidence for life in the Universe – but only on Earth.  Using a phenomenon known as Earthshine, where light from Earth is reflected off the surface of the Moon, researchers from the European Southern Observatory were able to view the Earth as if it were an exoplanet, and use the reflected light to look for tell tale signatures of life...

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[graham.d]

It is an interesting idea to make use of the fact that reflected light is polarised. I didn't understand how this would be applied to detect life on exoplanets though. I assume that they are not seeking a moon of an exoplanet (or another planet) to get the light 3rd hand (as it were) but just taking advantage of the light from the exoplanet's sun being polarised in being reflected from the exoplanet's surface. I can see that this would allow some filtering to be applied to remove much of the unpolarised light coming from its sun but I am surprised that the gain from this is sufficient to be useful; I suppose every little helps - are there any figures to show the advantage of such a method. A factor of two would be my guess but this light will still be highly swamped by the light from its sun.

[yor_on]

Very clever technique. Someone used his or hers mind there.