Credit: NASA Ames/SETI Institute/JPL-CalTech
Kepler Space Telescope was
launched in spring of 2009 and it has been hunting exoplanets ever since.
Recently Kepler Space Telescope found an Earth-twin (Kepler-186f); a planet
that is essentially like ours in terms of composition, habitability and size. Kepler
has recently confirmed the discovery of an exactly Earth-sized exoplanet and
this exoplanet is also in its star’s habitable zone. This announcement was made
at a press conference. The findings have also been published in Science.
Life as we know it needs the
presence of liquid water and a planet in order to support life would not be
too close to its parent star (which would be too hot and the water would be vaporize
in a short period of time) yet not too far away from its parent star (where it
would be too cold and the water would be frozen). Habitability on a planet
requires a “Goldilocks Zone” where conditions are just accurate to support life.
"We know of just one
planet where life exists -- Earth. When we search for life outside our solar
system we focus on finding planets with characteristics that mimic that of
Earth," said Elisa Quintana, lead author of the paper. "Finding a habitable
zone planet comparable to Earth in size is a major step forward."
Kepler-186f is nearly around
10% larger than Earth. Kepler-186f orbits an M dwarf star, which is around 500
light-years away in the constellation Cygnus. The parent star of Kepler-186f is
about half of the mass and the size of our sun. Kepler-186f takes about 130
Earth days to complete a revolution. On the outer edge of the star’s habitable
zone, the planet gets about a third of the radiation from its parent star just
like we do from ours.
In order to determine the
composition of planets out in the habitable zone using current technology isn’t
as easy as those who are extremely close to the star, because there isn’t as
much radiation from the star accessible to decide what is or isn’t getting
absorbed. Although previous discoveries have showed that Kepler-186f is a rocky
planet, more analysis must be done in order to reach any definitive conclusions.
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