Scientists find closest thing yet to Earth-sun twin system

CAPE CANAVERAL, Fla. -- Scientists have identified a "close cousin" to Earth that's orbiting a sun-like star and might harbor life.

"It is the closest thing that we have to another place that somebody else might call home," said Jon Jenkins from NASA's Ames Research Center in California.

The researchers announced their discovery Thursday based on observations from NASA's Kepler space telescope.

This older, bigger cousin to Earth is called Kepler-452b. What makes this planet remarkable is it orbits its star at about the same distance Earth orbits the sun.

What's more, its home star looks similar to our sun. Based on what scientists know today, Jenkins noted it's the nearest thing to another Earth-sun twin system.

"Today the Earth is a little less lonely, because there's a new kid on the block," Jenkins said during a news conference. He led the team that discovered Kepler-452b.

The last Kepler discovery that had scientists gushing was just over a year ago. That close-to-Earth-size planet, Kepler-186f, also was in the habitable zone of its star. But the faint dwarf star was unlike our sun.

John Grunsfeld, NASA's science mission chief, emphasized the exoplanet system identified Thursday -- "a pretty good close cousin to the Earth and our sun" -- is the closest so far. "And I really emphasize the 'so far.'"

The planet-hunting Kepler will keep churning out new discoveries, Grunsfeld noted, and possibly find even better matches for "Earth 2.0."

Kepler was launched in 2009 and has nearly 5,000 potential exoplanets to its credit -- worlds beyond our solar system.

It is helping to address such fundamental questions as where we come from and where are we headed, and arguably the biggest question of all: Are we alone in the universe?

Grunsfeld said thanks to Kepler's latest finding, we're taking "one small step in answering that question today."

While scientists are uncertain whether Planet 452b is rocky like Earth, they believe there's a better than even chance it is.

As for the age and size, it is about 6 billion years old, 1.5 billion years older than Earth, and 60 percent larger in diameter than our home planet.

Its star, Kepler 452, also is older and bigger, as well as brighter than our sun.

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