NASA has now confirmed that more than 5,000 planets exist outside our solar system, which is "just a fraction" of the likely hundreds of billions in our galaxy.
The planetary odometer turned on March 21, as NASA officially added 65 more planets to its Exoplanet Archive, bringing the total number of confirmed, detectable planets beyond our solar system to over 5,000 — with 35% of these planets being categorized as Neptune-like, 31% identified as "super-Earths," 30% as gas giants, and only 4% terrestrial.
The percentages represent the variety of planets that have been discovered so far, with some being similar to those in our solar system, and others vastly different. There are "small, rocky worlds like Earth, gas giants many times larger than Jupiter, and hot Jupiters" as well as "super-Earths, which are possible rocky worlds bigger than our own, and mini-Neptunes."
"It's not just a number," said Jessie Christiansen, science lead for the archive and a research scientist with the NASA Exoplanet Science Institute at Caltech in Pasadena, in a statement accompanying the announcement. "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."
The Jet Propulsion Laboratory shared a video to celebrate the cosmic milestone, which was largely achieved by using powerful telescopes, both in space and on the ground. The first confirmed planetary discovery arrived in the 1990s when astronomer Alexander Wolszczan and his colleagues published a paper showing evidence of two planets orbiting a pulsar.
"To my thinking, it is inevitable that we'll find some kind of life somewhere–most likely of some primitive kind," Wolszczan said, noting how the "close connection between the chemistry of life on Earth and chemistry found throughout the universe, as well as the detection of widespread organic molecules, suggests detection of life itself is only a matter of time."
Thousands of planets logged in the archive were found using NASA's Kepler Space Telescope, and there are likely hundreds of billions more to discover with next-gen instruments. The James Webb Space Telescope was recently launched to assist research into habitable conditions, while the Nancy Grace Roman Space Telescope is expected to launch in 2027.
Astronomers previously discovered 139 new "minor planets" in the far reaches of our solar system, just beyond Neptune's orbit. The vast expanse of the galaxy also plays host to a free-floating world without a host star, a "hell planet" that is strangely similar to Darth Vader's lava homeworld of Mustafar, and a Super-Earth that's nearly as old as the universe itself.
Adele Ankers-Range is a freelance writer for IGN. Follow her on Twitter.
Thumbnail image credit: NASA/JPL-Caltech.
Source: IGN.com NASA Has Now Confirmed More Than 5,000 Planets Outside Our Solar System