The University of Hawaii played a big role in another significant astronomical discovery announced Monday.

Astronomers now estimate that one in five stars in our galaxy that are similar to the sun have an earth-like planet.

Over the past four years, NASA's Kepler spacecraft has been scanning the Milky Way galaxy, looking for other planets like ours.

"Kepler looked at 150-thousand stars and it hunted for Earth-like planets around each one of them, and we counted those planets very carefully and we came up with an estimate that about 20 percent of stars like the sun have a planet that's about the size of the Earth, in an orbit that's about like the Earth's orbit," said University of Hawaii Institute for Astronomy faculty member Andrew Howard.

He was one of three scientists associated with the findings, which were published online in the journal "proceedings of the National Academy of Sciences" on Monday.

The team of researchers looked for Earth-sized planets with orbits in a habitable zone. An orbit too close to its star is too hot for life. Too far, too cold.

Howard said the study was far too short to scan all of the stars in the Milky Way.

"You can think of it like taking a census. You don't have time to knock on every single door. So you just knock on one neighborhood's worth of doors and that tells you about the entire population," he said.

"There's a hundred-billion stars in our galaxy. So 20 percent of that is a huge number. that's more Earth-like planets than there are people on the Earth."

But Howard warns, it's unknown how many of these planets are rocky with a similar atmosphere to Earth, making it capable for life.

Originally posted here:

UH researchers make another big astronomy discovery