Astronomers Find Clues for Alien Life on the Planet Most like Earth: Kepler-452b

SYFY:  Using data collected by the Kepler Space Telescope and ground observations at the McDonald Observatory in Texas, the Whipple Observatory in Arizona, and the Keck Observatory in Hawaii, astronomers confirmed the presence of Kepler-452b, roughly 1,400 light-years from here. The discovery was published in The Astronomical Journal. It is noteworthy as the first near-Earth-size planet in the habitable zone of its star. In fact, it’s the smallest planet ever found inside a habitable zone, with a diameter roughly 60% larger than the Earth.

Comparison of Earth and Kepler-452b

The artistic concept compares Earth (left) to the new planet, called Kepler-452b, which is about 60 percent larger. The illustration represents one possible appearance for Kepler-452b. Photo: NASA/Ames/JPL-Caltech/T. Pyle

“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. This exciting result brings us one step closer to finding an Earth 2.0,” said John Grunsfeld, associate director of NASA’s Science Mission Directorate, in a statement.

There is still a lot of basic science to do before we start dreaming up interstellar ships and plot a course to Kepler-452b. We’re not even totally sure what the planet is made of. It’s possible that 452b is a sub-Neptune with a solid core covered in a layer of ice and blanketed in a thick atmosphere. However, planets of this size are more than likely rocky, according to NASA.

In addition to being roughly Earth-sized and lying within its star’s habitable zone, Kepler-452b is like Earth in some other ways. It orbits at a distance about 5% further from its star than the Earth is from the Sun. As a result, its year is almost the same length as ours, at roughly 385 days. All things considered, living there might be pretty similar to living here. Or it might have been, once upon a time.

A comparison of the Kepler-452 system compared alongside the Kepler-186 system and the solar system.

Size and scale of the Kepler-452 system compared alongside the Kepler-186 system and the solar system. Photo: NASA Ames/JPL-CalTech/R. Hurt

The system’s estimated age is roughly 6 billion years, about 1.5 billion years older than the Sun. That could mean that life there got a headstart on us, assuming the conditions are suitable. “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 a substantial opportunity for life to arise, should all the necessary ingredients and conditions for life exist on this planet,” said Kepler data analyst lead, Jon Jenkins.

While 452b might be the most immediately exciting planet in the bunch, the team also identified 521 additional exoplanet candidates, bringing Kepler’s total up to 4,696. Considering how many worlds we find practically everywhere we look, it’s likely we’ll continue to find places that are more and more like the Earth. We might even find someplace we can dream about going to visit ourselves. When we do finally leave Earth in search of someplace else, hopefully we’ll have a better candidate than Proxima centauri b.

* Proxima сentauri b - The planet orbits very close to its star Proxima сentauri, less than 5% of Earth's distance from the Sun, and completes a year every 11.2 two days and is approximately 4.2 light-years from Earth.