Cousin planet.

Astronomers have finally confirmed, NPR reports, the discovery of the very first Earth-like planet somewhere else in space:

Astronomers have found hundreds of planets outside our solar system, but most are behemoths – larger than Jupiter – and many are made mostly of gas.

The new planet was found by NASA’s Kepler space telescope, which was designed to look for much smaller, solid planets more like Earth. At a news conference Monday at the American Astronomical Society meeting in Seattle, researchers said they’d found one.

“I’m here today to announce the discovery of Kepler’s first rocky planet: Kepler-10b,” said Natalie Batalha, the deputy science team leader for NASA’s Kepler space telescope. Kepler-10b is only 40 percent larger than Earth.

“You’ve got 10,000 light bulbs, and you take just one away — that’s the brightness change we’re trying to measure,” she said.