NASA Says It Has Found The Most 'Earth-Like' Planet Yet
NASA announced today that they found a distant world that reminds us of home more than any other planet we've found.
The telescope Kepler has been on a mission since 2009 to find planets in other star systems that could support that essential ingredient to life: liquid water. The planet has to be the right size and it has to be in that Goldilocks zone: not too hot and not too cold. The planet named Kepler-186f fits the bill.
It's about 500 light-years away from earth in the constellation Cygnus. It's a part of the Kepler-186 star system along with four other planets that circle a red dwarf, which is promising because red dwarves make up 70 percent of the stars in our galaxy. The diameter of the planet is only 10% larger than the Earth—that makes it the smallest planet discovered by Kepler so far, according to the Los Angeles Times. Size is key, because even a planet with 50% more mass would have enough gravity to pull in a thick layer of hydrogen-helium in its atmosphere that would be too thick for life as we know it.
This newly-discovered planet is much closer to its star than we are to ours: it circles its star every 130 days. But scientists say the planet gets only about a third of the energy Earth does, since its red dwarves are pretty dim. The light it gets at high noon is about the same as the light we get about an hour before sunset. It's not exactly like the Earth, but it's as close as we've gotten so far.
"Kepler-186f can be thought of as an Earth-cousin rather than an Earth-twin. It has many properties that resemble Earth," Thomas Barclay, a scientist at the Bay Area Environmental Research Institute at Ames and a co-author of the paper announcing discovery, said in a release.
There's still a lot we don't know about this planet. Scientists are guessing Kepler-186f is rocky. However, they still don't know just how much mass the planet has or what it's made up of—much less whether there is actually any kind of water on the surface. But it's a pretty promising step in the search for life on other worlds.
Here's a diagram that shows what the star system of this newly-discovered looks like compared to our own:
NASA's Jet Propulsion Laboratory in Pasadena managed the Kepler mission development while NASA's Ames in the Bay Area is responsible for mission operations and data analysis.