New findings show nearby earth-sized planets could have more water than us

SEATTLE -- Seven planets orbiting a not-so-distant star may have water, a key component to hosting life. In fact, given the density of a few of the planets, they may have more liquid water than Earth, new findings show .

The findings, compiled by a team of astronomers including some from the University of Washington, show the planets orbiting the star TRAPPIST 1 could have up to 5 percent of their mass in the form of water.

Some of the planets may have steamy, rich atmospheres, consistent with Earth's.

"It's not totally implausible that these planets have water," said University of Washington Professor Eric Agol.

TRAPPIST 1 is an ultra-cool dwarf star about 40 light-years from Earth. Seven earth-sized planets orbit the star closer than Mercury orbits the Sun.

But because TRAPPIST 1 is so dim, all of the planets fall within the "Habitable Zone" - a distance from the star that could foster liquid water.

Astronomers determined the planets were present using NASA's Spitzer Space Telescope,  focusing on TRAPPIST 1 and noting when it would dim. The star was interesting watch, Agol said, in part because it's only about eight times bigger than Jupiter.

"By star standards, it's a puny star," Agol said.

Puny, but relatively close. Forty light-years away is nearly in Earth's backyard.

"That's our neighborhood," Agol said.

Of course, it's not certain the density of each planets show they have water. They may be made up of less iron than nearby planets, or the density could be comprised of different elements.

And even if scientists did determine water was on the surface, we're nowhere close to traveling to the planet, Agol said. The planets are about 1 million times farther away than Mars.

"It's just a vast distance to cover," Agol said. "But that's what science fiction is for ... you never know."

The next step in studying these planets will be to determine their atmospheric composition.

For more on the planets and the University of Washington's studies, head to the university's website.