Astronomers have found a planet they say is “the closest twin to Earth” ever seen.
Kepler-452b, it is the smallest planet discovered orbiting in the
habitable zone of a star, and has been described as an “older, bigger
What makes this planet remarkable is that it orbits its
star at about the same distance that Earth orbits the sun. What’s more,
its home star looks to be similar to our sun.
world has a “substantial opportunity” to host life, Nasa says, adding
that if plants were transferred there, they would likely survive.
The planet is about 60 per cent bigger than Earth, and is located about 1,400 light years away in the constellation Cygnus.
Its discovery brings the total number of confirmed planets to 1,030.
has also found 12 new small habitable zone candidate planets, marking
another milestone in the journey to finding another “Earth.”
It is “the closest twin to Earth, or the Earth 2.0 that we’ve
found so far in the dataset”, said John Grunsfeld, associate
administrator of Nasa’s Science Mission Directorate.
Kepler-452b is larger than Earth, but its 385-day orbit is only 5 per cent longer.
resides in something known as the habitable zone – or Goldilocks zone –
which is an area around a star where liquid water could pool on the
surface of an orbiting planet.
It is also 5 per cent farther from its parent star Kepler-452 than Earth is from the sun.
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.
could even get a healthy tan like here on holiday. Getting to our
closest twin planet might take a while though, since it’s 1,400 light
Kepler-452 is 6 billion years old, 1.5 billion years
older than our sun, has the same temperature, and is 20 per cent
brighter and has a diameter 10 per cent larger.
While its mass
and composition are not yet known, previous research suggests that
planets the size of Kepler-452b have a good chance of being rocky.
can think of Kepler-452b as an older, bigger cousin to Earth,” said Jon
Jenkins, Kepler data analysis lead at Nasa’s Ames Research Center.
“It’s awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star’ longer than Earth.
substantial opportunity for life to arise, should all the necessary
ingredients and conditions for life exist on this planet.”
help confirm the finding and better determine the properties of the
Kepler-452 system, the team conducted ground-based observations.
measurements were key for the researchers to confirm the planetary
nature of Kepler-452b, to refine the size and brightness of its host
star and to better pin down the size of the planet and its orbit.
452b could be experiencing now what the Earth will undergo more than a
billion years from now,’ said Doug Caldwell, a Seti Institute scientist
on the Keplar mission.
“If Kepler 452b is indeed a rocky planet,’
he said, its location ‘could mean that it is just entering a runaway
greenhouse phase of its climate history.
“Its ageing sun might be
heating the surface and evaporating any oceans. The water vapour would
be lost from the planet forever.”
The research paper reporting this finding has been accepted for publication in The Astronomical Journal.
well as confirming Kepler-452b, the Kepler team has increased the
number of new exoplanet candidates by 521 from their analysis of
observations conducted from May 2009 to May 2013, raising the number of
planet candidates detected by the Kepler mission to 4,696.
of the new planet candidates have diameters between one to two times
that of Earth, and orbit in their star’s habitable zone.
Of these, nine orbit stars that are similar to our sun in size and temperature.
been able to fully automate our process of identifying planet
candidates, which means we can finally assess every transit signal in
the entire Kepler dataset quickly and uniformly,’ said Jeff Coughlin,
Kepler scientist at the SETI Institute.
“This gives astronomers a
statistically sound population of planet candidates to accurately
determine the number of small, possibly rocky planets like Earth in our
Milky Way galaxy.”
These findings, presented in the seventh Kepler Candidate Catalog, will be submitted for publication in the Astrophysical Journal.
Last year astronomers announced the telescope had spotted its first Earth-sized planet in the habitable zone of another star.
Kepler-186f, which is around 500 light years from Earth, was the first planet to be discovered that is reminiscent of our own.
January Nasa announced another two new planets – Kepler 438b, which is
thought to be only 12 per cent bigger than Earth, and Kepler-442b, which
is thought to be 33 per cent bigger.
In July, Kepler spotted
five planets orbiting around the same star – Kepler-444 – all of which
are thought to be close to the size of Earth.
director of astrophysics at Nasa, said identifying worlds that could be
home to alien life with Kepler would allow future missions to look at
them more closely.
He said: “Future Nasa missions, like the
Transiting Exoplanet Survey Satellite and the James Webb Space
Telescope, will discover the nearest rocky exoplanets and determine
their composition and atmospheric conditions, continuing humankind’s
quest to find truly Earth-like worlds.”