Decades and decades spent in trying to find life beyond our planet, NASA has finally come across one very similar in size to the Earth with the potential of being habitable. NASA’s Kepler mission has recently confirmed the discovery of the smallest planet (named Kepler-452b) to be found orbiting in what is called the “habitable zone”. The latter is the region surrounding a star where water in its liquid form can come to the surface of the orbiting planet. Ah, does sound promising for life to exist, right?!
An artist’s impression of Earth compared to Kepler 452b. Photo credits: NASA/JPL-Caltech/T. Pyle.
Kepler-452b’s star – a G2-type star – bears resemblance to our own sun. Furthermore, the Earth-like planet orbits its sun at nearly the same distance our planet is to our sun. This marks an unprecedented discovery because it is the first time that a planet resembling our own has been spotted. Could it really be “another Earth”?
“On the 20th anniversary year of the discovery that proved other suns host planets, the Kepler exoplanet explorer has discovered a planet and star which most closely resemble the Earth and our Sun,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “This exciting result brings us one step closer to finding an Earth 2.0.”
It was through the Kepler Space Telescope that the planet was observed. It is currently at 1,400 light-years away from us. It is 1.6 times the size of Earth, and it hence falls under the category of “super-Earth”. According to scientists, it might be a rocky world. Its sun is 4 % more massive and 10 % brighter than our sun.
The planet’s full revolution takes 384.84 Earth days. It is 5 % more distant from its sun than ours: at this distance, it is in the star’s habitable zone, where it is of the ideal temperature for water to exist there in its liquid form.
“Sun-like stars are people’s favorites, because we know of one circumstance [Earth] where that paid off [for life],” said Seth Shostak, the Director of SETI (Search for Extraterrestrial Intelligence), which participated in the discovery, in a statement to IFLScience.
The new planet together with Kepler 186f seen as potentially Earth-like worlds. Photo credits: NASA Ames/SETI/JPL-Caltech.
“We can think of Kepler-452b as an older, bigger cousin to Earth, providing an opportunity to understand and reflect upon Earth’s evolving environment,” said Jon Jenkins, Kepler data analysis lead at NASA’s Ames Research Center in Moffett Field, California, who led the team that discovered Kepler-452b. “It’s awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star; longer than Earth. That’s substantial opportunity for life to arise, should all the necessary ingredients and conditions for life exist on this planet.”
Kepler-452b’s sun is, however, 1.5 billion years older than our sun. While this might imply that its chance of being inhabitable would be low, the planet could be used as a model to analyse what could happen to our own planet in the future.
“If Kepler 452b is indeed a rocky planet, its location vis-a-vis its star could mean that it is just entering a runaway greenhouse phase of its climate history,” Doug Caldwell, a SETI Institute scientist working on the Kepler mission, said in a statement. “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.”
Regardless of how low the chances are, could it be that Kepler-452b might have been habitable at one point or another?
“Kepler 452b is one small step in answering the question [of are we alone] today,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate, in a press conference.