Orphan planets — ones floating in space without stars to orbit — are likely much more common than astronomers thought.

In fact, there could be twice as many so-called “free-floating planets” as there are stars, NASA officials said Wednesday.

The planets were likely ejected from solar systems during in formational periods, and now they’re lurking in the cold, dark areas between known parts of space.

A joint survey between astronomers in Japan and New Zealand took stock of the planets in the center of the Milky Way galaxy during 2006 and 2007. They found evidence of 10 “orphan planets” lurking in the darkness, each one roughly the mass of Jupiter.

The survey’s findings imply there are more free-floating planets that are so-far undetected — probably twice as many as there are stars. Researchers also estimate the orphan planets are at least as common as those orbiting stars.

“This would add up to hundreds of billions of lone planets in our Milky Way galaxy alone,” NASA officials said in a prepared statement.

But how do astronomers know for sure? The short answer is that they don’t — but the survey acts as a census of sorts.

“We sampled a portion of the galaxy, and based on these data, can estimate overall numbers in the galaxy,” said David Bennett, a NASA and National Science Foundation-funded co-author of the study.

The fact that astronomers detected 10 planets instead of just a couple indicates they were likely ejected from solar systems. Previously, scientists thought planets formed like stars, growing from collapsing balls of gas and dust.

“If free-floating planets formed like stars, then we would have expected to see only one or two of them in our survey instead of 10,” Bennett said. “Our results suggest that planetary systems often become unstable, with planets being kicked out from their places of birth.”

It’s possible the planets could be formed by varying means — ejection and star-like generation.

NASA officials say the survey wasn’t capable of detecting planets smaller than Jupiter and Saturn, but it’s likely that smaller planets the size of Earth would be ejected from solar systems more often.

“As a result, they are thought to be more common than free-floating Jupiters,” according to NASA.

The planets detected in the survey are located roughly 10,000 to 20,000 light-years from Earth.

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