Prompts winter weather advisories as cold air moves in Friday night

MPR News helps you turn down the noise and build shared understanding. Turn up your support for this public resource and keep trusted journalism accessible to all. 

Turn Up Your Support

In a milestone for astronomy — and possibly the search for extraterrestrial life – 

NASA's Jet Propulsion Laboratory confirmed

 there are now 5,000 known planets beyond 

These so-called exoplanets include rocky worlds roughly the size of Earth, gas giants larger than Jupiter and "mini-Neptunes."

"It's not just a number," Jessie Christiansen, science lead for the NASA Exoplanet Archive and a research scientist with the NASA Exoplanet Science Institute at Caltech, said in a statement.

"Each one of them is a new world, a brand-new planet. I get excited about every one because we don't know anything about them," Christiansen added.

Scientists are getting better at discovering them

Scientists' ability to find new exoplanets is exploding, with a growing understanding of how to locate planets beyond our solar system and the technological tools to do it, such as the 

 launched in 2018 and the recently launched 

Our galaxy is likely home to billions of exoplanets, NASA says. And the truth about extraterrestrial life may be out there.

"To my thinking, it is inevitable that we'll find some kind of life somewhere – most likely of some primitive kind," said Alexander Wolszczan, the lead author of a 1992 paper that confirmed the first exoplanets.

Of the 5,000 planets found so far, 35 percent are Neptune-like, similar in size to Neptune or Uranus and can be ice giants or much warmer. Around 31 percent are called 

 – ranging in size from Earth to Neptune and possibly rocky – while 30 percent are gas giants.

Astronomers discovered the first exoplanets by using the "wobble" method of tracking the subtle teetering of a star caused by the gravitational pulls of orbiting planets.

Then they sent up a space telescope and had it look at more than 170,000 stars, watching for dips in light that would indicate a planet passed by. This is known as the "transit" method, and it's how 

most of the known exoplanets have been found

Science

Joe Hernandez

Author

These so-called exoplanets include rocky worlds similar in size to Earth, gas giants larger than Jupiter and even"'mini-Neptunes."

There are more than 5,000 confirmed planets beyond our solar system, NASA says

Go Deeper.

Like this?