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In
April 2007, astronomers announced the discovery of the most Earth-like
planet so far found outside our Solar System. This planet is not
much bigger than the Earth. It orbits the faint star Gliese 581,
which is 20.5 light-years away in the constellation Libra. The mean
temperature of this ‘'super-Earth' is between 0 and 40 degrees
Celsius, which means that any water there could exist in liquid
form.
Its radius is estimated at
only 1.5 times the Earth's radius, and models predict that the planet
could be either rocky, or covered with oceans. It will become the
prime target for telescopes in space that can discern the tell-tale
light signs of biological processes. The orbiting observatories
would look for trace atmospheric gases like methane, or signs of
chlorophyll, essential to plant life on Earth. See: ‘'Red
Edge / Earth Shine'. |
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