NASA has announced the discovery of the most Earthlike planet ever detected: Kepler-452b. This tantalizing world is located some 1,400 light years away in the constellation Cygnus, where it orbits a star remarkably like our Sun.
The new planet is about 60 percent larger than Earth, but that's actually small for Earth analogs discovered so far—so small, in fact, that it set a new record as the tiniest planet ever found in the habitable zone of a Sun-like star.
On top of all that, Kepler-452b even has an Earthlike year, circling its star every 385 days, at a distance only five percent farther than Earth's position relative to the Sun.
Skeptics might point out that the Kepler space observatory has discovered several so-called "Earthlike" planets over its six years in orbit, but the below figure demonstrates how exceptional Kepler-452b is compared to previous exoplanets.
Is it really all that Earthlike?
There have been many near-Earth-sized planets found in the habitable zones of M and K class stars (red and orange dwarfs, respectively), and there have been planets that are many times larger than Earth found in the habitable zones of G2-type stars like our Sun. But this is the first time that all of these variables have aligned to produce such an uncannily familiar portrait of our own solar system.
"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 NASA associate administrator John Grunsfeld during a NASA livefeed of the announcement.
"This exciting result brings us one step closer to finding an Earth 2.0," he added.
What's more, the Kepler-452 system predates our own solar system by about 1.5 billion years, suggesting it has had ample time to host life, if the right materials are there.
"It's awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star; longer than Earth," said Kepler data analysis lead Jon Jenkins in the live feed. "That's substantial opportunity for life to arise, should all the necessary ingredients and conditions for life exist on this planet."
Video explainer about Kepler-452b. Credit: NASA Ames Research Center
Are there more?
Of course, just because Kepler-452b is the new top dog as far as Earthlike planets go doesn't mean it won't get ousted by an even more closer match down the line.
Indeed, the mission leads on today's livefeed took pains to emphasize that the new planet is one of 521 new planets that will be announced in the seventh Kepler Candidate Catalog, forthcoming from The Astrophysical Journal.
According to a NASA statement released today, "twelve 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."
The newest batch of planets brings Kepler's total findings to a whopping 4,696 candidate worlds beyond our own. Considering that the first exoplanet was discovered only 20 years ago, that is a seriously impressive haul.
Plus, as exciting as it is to recognize our own planet in candidates like Kepler-452b, there is something to be said for the sheer diversity of planets—Earthlike or not—that we now know exist in our galaxy. Kepler has rooted out hot Jupiters and wobbly planets and Tatooine analogs, and no doubt it will continue to make even more curious discoveries down the line.