Is our world unique? Is it the only one in existence, or are there others – perhaps many others – out there? Do other beings – maybe even intelligent ones – call these worlds their home, and live out their lives completely unbeknownst to us?
It was only in 1995 that we first discovered evidence that other stars had planets, as ours does. Now we have detected many thousands of other worlds, and evidence suggests that a majority of sun-like stars possess them. Most of these stellar systems bear little resemblance to ours. The easiest planets to detect are massive worlds located close to their stars, so "hot Jupiters" dominate the current list of exoplanets. As our surveys continue, however, we are discovering more and more Neptunes and even super-Earths, in orbits farther and farther from their suns.
How are scientists searching for extrasolar planets? Read here of the different approaches, their strengths and weaknesses, and how planet hunters are pursuing them all.
We recommend the Paris Observatory's Extrasolar Planets Encyclopaedia. The Planetary Society no longer maintains our own Catalog of Exoplanets.
FINDS Exo-Earths is a fiber-optic spectrograph technology that helps exoplanet hunters look for worlds beyond our solar system.
A collection of multimedia related to our exoplanets projects.
Our newest sponsored project uses a triple-laser system to support precise, long-term spectrograph calibrations.
Are there Earth-like planets around our nearest stellar neighbor?
Mark Marley • April 02, 2019 • 1
Mark Marley explains what planetary scientists mean when they say the word "ice."
Hannah Wakeford • March 12, 2019
A GREAT QUEST is underway to discover Earthsize worlds in their stars’ habitable zones. Along the way, astronomers have been surprised to learn that the most typical size of planet in our galaxy is one with no counterpart in our own solar system.
Jason Davis • October 30, 2018 • 4
NASA's Kepler space telescope helped us find our place in the cosmos.
Jason Davis • June 04, 2018 • 1
NASA and the National Science Foundation are teaming up to observe exoplanets discovered by Kepler and TESS.
Franck Marchis • April 30, 2018 • 1
One year ago, Franck Marchis wrote an article about the remarkable discovery of the TRAPPIST-1 system. Here's an update.
Jason Davis • November 15, 2017 • 3
And it's only 11 light-years away.
Jason Rhodes • June 23, 2017 • 8
Starshade is a proposed flower-shaped spacecraft that can create an artificial eclipse, allowing space telescopes to spot planets orbiting distant stars.
Franck Marchis • February 22, 2017 • 14
Scientists have found seven, Earth-size planets orbiting a star just 40 light years away. Three lie in the habitable zone and could have water on their surfaces.
Erika Nesvold • October 31, 2016
At this year’s Division for Planetary Sciences/European Planetary Science Congress meeting, the Exoplanet Dynamics session was packed full of talks on tightly-packed multi-planet systems and their instabilities.
Franck Marchis • August 24, 2016 • 19
What began as a tantalizing rumor has just become an astonishing fact. Today a group of thirty-one scientists announced the discovery of a terrestrial exoplanet orbiting Proxima Centauri. The discovery of this planet, Proxima Centauri b, is a huge breakthrough not just for astronomers but for all of us. Here’s why.
