PHYSICS WORLD
A study of light from the Earth that has bounced off the Moon could help astronomers in their search for life on distant planets. That is the claim of astronomers in Chile, the UK and Spain who have showed that faint light from the Earth contains strong signals of the biological processes that occur on our planet.
So far about 760 extrasolar planets – or exoplanets – have been discovered orbiting stars other than the Sun. The ultimate goal of many astronomers studying exoplanets is to determine whether some of them harbour life. Doing so will likely involve spectroscopic studies of the light that is absorbed and/or emitted from the exoplanet to look for large quantities of molecular oxygen and methane in the atmosphere that could be signatures of life. Astronomers would also be looking for a sharp change in the planet’s reflectivity as a function of wavelength – which would occur if an exoplanet had vegetation similar to that on Earth.
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