NASA Earth discovery is a second home

July 25, 2015 2:45 am

has found a twin Earth orbiting a star like the sun in the Milky Way which scientists say “would feel a lot like home”.
Kepler
452b — which has been dubbed Earth 2.0 — is six billion years old,
has a 385-day year and orbits its star at the same distance as Earth. It
is 1400 light years away in the constellation Cygnus.
It is
believed to be rocky, with active volcanoes and is so like Earth that
Nasa believes it is possible life once inhabited the planet.

An impression by a Nasa artist compares Earth with what scientists believe the new planet could look like. Photo / AP
Similar light, temperatures, yearly orbit have scientists saying Kepler 452b could have been another Earth.
Scientists said that the sunshine is so similar that plants could survive if taken to Kepler 452b.
“This
is so fascinating because Kepler 452b receives the same kind of
spectrum and intensity of light as we do on Earth,” said Dr Daniel
Brown, an astronomy expert at Nottingham Trent University.
“This
means plants from our planet could grow there if it were rocky and had
an atmosphere. You could even get a healthy tan like here on holiday.”
But because it’s 1.5 billion years older, scientists say it gives a
“peek into a crystal ball showing a possible future for Earth” as it
reaches a point where it is no longer habitable.

“If Kepler 452b is indeed a rocky planet, its location could
mean that it is just entering a runaway greenhouse phase of its climate
history,” said Doug Caldwell, a SETI Institute scientist working on the
Kepler mission.
“The increasing energy from its ageing sun might
be heating the surface and evaporating any oceans. The water vapour
would be lost from the planet forever.
“Kepler 452b could be
experiencing now what the Earth will undergo more than a billion years
from now, as the sun ages and grows brighter.”
The Kepler
spacecraft has been looking for signs of new worlds outside the solar
system since May 2009, and has so far found more than 4000 planets in
the so-called Goldilocks Zone — neither too hot, nor too cold to
sustain life.
Yesterday Nasa announced it had found 500 new
possible planets to add to the 4175 already found by the telescope, and
12 were “Earth-like”. But Kepler 452b is the first of the 12 to be
confirmed as a planet and Nasa said it was the “closest” to Earth that
has ever been seen.
It is 60 per cent larger in diameter than Earth and is considered a super-Earth-size planet.
“Today
the Earth is a little less lonely because there is a new kid on the
block,” said Jon Jenkins, Kepler data analysis lead at Nasa’s Ames
Research Centre in Moffett Field, California. “If you travelled to this
star with an arkful of plants … the plants would photosynthesise just
perfectly fine. It would feel a lot like home from the standpoint of the
sunshine.
“It is six billion years old. That is considerable
opportunity for life to arise on its surface and its oceans should all
the necessary conditions for life have appeared on this planet.
“This
is the closest thing that we have to another planet like the Earth. And
the Earth follows nearly in the footsteps of its older cousin and will
be there in 1.5 billion years time.”
The discovery gives new hope that alien civilisations may exist beyond the solar system.
This
week Professor Stephen Hawking and the Astronomer Royal Lord Martin
Rees announced they were joining a $100 million ($151.7 million)
project to seek out signs of extra-terrestrial intelligence in the Milky
Way.
“We won’t be going to this planet but our children’s
children’s children might be,” said Jeff Coughlin, Kepler research
scientist at the SETI Institute in California.
Kepler’s task is
to look for rocky planets between half and twice the size of Earth where
water could still exist on the surface. The size of the planet also
means it has enough gravity to pull in gases like hydrogen and helium to
form an atmosphere.
The observatory detects planets as
their orbits cross in front of their star and cause a very tiny but
periodic dimming of the star’s brightness. Nasa is also trying to
determine the fraction of the hundreds of billions of stars in our
galaxy that might have such planets.

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