A newly discovered exoplanet, Kepler-452b, comes the closest of any found so far to matching our Earth-sun system. This artist’s conception of a planetary lineup shows habitable-zone planets with similarities to Earth: from left, Kepler-22b, Kepler-69c, the just announced Kepler-452b, Kepler-62f and Kepler-186f. Last in line is Earth itself. Illustration by NASA/Ames/JPL-Caltech
Earth just got a new cousin. NASA’s Kepler telescope has discovered a new planet that is the closest mimic of our celestial home ever known.
Stare at the constellation Cygnus in the night’s sky, and you’ll be looking straight at this newly discovered world, which NASA has dubbed Kepler-452b. Located 1,400 light-years away, Kepler-452b shares many features with Earth. Its orbit lasts 385 days compared to our 365 days. That means Kepler-452b exists a habitable distance away from its parent star, and water might be able to pool on its surface. NASA scientists says that Kepler-452b’s surface has a good chance of being rocky, too.
Scientists using data from NASA’s Kepler mission have confirmed the first near-Earth-size planet orbiting in the habitable zone of a sun-like star. Illustration by NASA/Ames/JPL-Caltech/T. Pyle
“This exciting result brings us one step closer to finding an Earth 2.0,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate in a statement.
Kepler-452b is 60 percent bigger than Earth, and its sun is 1.5 billion years older than our own. However, its sun falls into the same class as ours — G2-type star — meaning the two fireballs share similar temperatures.
The sweep of NASA Kepler mission’s search for small, habitable planets in the last six years. The first planet smaller than Earth, Kepler-20e, was discovered in December 2011 orbiting a Sun-like star slightly cooler and smaller than our sun every six days. But it is scorching hot and unable to maintain an atmosphere or a liquid water ocean. Kepler-22b was announced in the same month, as the first planet in the habitable zone of a sun-like star, but is more than twice the size of Earth and therefore unlikely to have a solid surface. Kepler-186f was discovered in April 2014 and is the first Earth-size planet found in the habitable zone of a small, cool M dwarf about half the size and mass of our sun. Kepler-452b is the first near-Earth-Size planet in the habitable zone of a star very similar to the sun. Illustration by NASA Ames/W. Stenzel
“We can think of Kepler-452b as an older, bigger cousin to Earth,” said Kepler’s lead data analyst Jon Jenkins of NASA’s Ames Research Center, in a statement.
Since their last announcement in January, the Kepler mission has discovered 521 new exoplanets, including Earth’s new cousin. That brings the mission’s tally to 4,696 planet discovered since its launch in 2009. A dozen of those are Earth-sized, or fall within one to three times our planet’s diameter. And nine orbit stars with a similar temperature and size to our sun. The announcement of Kepler-452b was made today at NASA headquarters in Washington, D.C.
Of the 1,030 confirmed planets from Kepler, a dozen are less than twice the size of Earth and reside in the habitable zone of their host stars. In this diagram, the sizes of the exoplanets are represented by the size of each sphere. These are arranged by size from left to right, and by the type of star they orbit, from the M stars that are significantly cooler and smaller than the sun, to the K stars that are somewhat cooler and smaller than the sun, to the G stars that include the sun. The sizes of the planets are enlarged by 25 times compared to the stars.
Photo by NASA/Ames/JPL-Caltech
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