Extrasolar Planets

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 to Search for Exoplanets

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.

Catalog of Exoplanets

We recommend the Paris Observatory's Extrasolar Planets Encyclopaedia. The Planetary Society no longer maintains our own Catalog of Exoplanets.

Latest Blogs

The Habitable Zone of Inhabited Planets

Posted by Jaime Green on 2014/07/07 03:14 CDT | 10 comments

A team of Colombian researchers are arguing for a new refinement to the idea of the habitable zone that takes the presence of life itself into account.

The nearly circular orbits in our solar system, not drawn to scale

How Weird Is Our Solar System?

Posted by Jaime Green on 2014/05/05 10:54 CDT | 6 comments

Earth and its solar system compatriots all have nearly circular orbits, but many exoplanets orbit their stars on wildly eccentric paths. Is our home system strange? Or is our sense of the data skewed?

Bruce Betts screen shot teaching CSUDH Introductory Astronomy class with Saturn in background.

Intro Astronomy 2014. Class 11: Exoplanets and Solar System Origin and Formation

Posted by Bruce Betts on 2014/04/25 04:30 CDT

Learn about the formation and origin of the Solar System and go beyond our neighborhood to investigate exoplanets (planets around other stars) in this video of class 11 of Bruce Betts' Introduction to Planetary Science and Astronomy class.

Apparent trajectory of Alpha Centauri B around Alpha Centauri A

Update on the search for planets in the Alpha Centauri system

Posted by Bruce Betts on 2014/04/04 10:29 CDT | 2 comments

Update from Debra Fischer and her team on the intriguing results of their observations of the main Alpha Centauri stars, as well as future plans.

Take My Free Online College Introduction to Planetary Science and Astronomy CSUDH Class

Posted by Bruce Betts on 2014/02/05 05:02 CST | 8 comments

Our own Dr. Bruce Betts is once again teaching his Introduction to Planetary Science and Astronomy college course online. Come join him.

Beta Pictoris b from the Gemini Planet Imager

Planetary Radio: The Gemini Planet Imager

Posted by Mat Kaplan on 2014/01/14 11:06 CST | 1 comment

It's very nice to infer the existence of planets circling other stars. It's even better to see them. This new instrument has just become the most powerful exoplanet viewer yet created.

Alpha Centauri Planet Hunt Update

Posted by Bruce Betts on 2013/10/15 11:27 CDT | 2 comments

An update from Yale’s Debra Fischer about the Alpha Centauri planet hunt, partially sponsored by The Planetary Society, as well as her team’s efforts to remove “noise” from parent stars to help find exoplanets.

Europe Will Select Its Next Major Science Mission in November

Posted by Van Kane on 2013/09/25 01:22 CDT | 2 comments

The European Space Agency will announce two major science missions this November, one of which is likely to be devoted to solar system exploration.

Destiny or Chance Revisited, by Stuart Ross Taylor

Book review: Destiny or Chance Revisited

Posted by Emily Lakdawalla on 2013/09/04 01:02 CDT | 1 comment

What have the recent discoveries of thousands of exoplanets told us about how we got here, and whether we are alone? In Destiny or Chance Revisited, Stuart Ross Taylor attempts to answer those two questions.

Upgraded Alpha Centauri Planet Search Underway

Posted by Bruce Betts on 2013/07/26 04:32 CDT

The Planetary Society sponsored Alpha Centauri planet search started using a newly upgraded system in May. Here is a quick update including info from project leader Debra Fischer from Yale about their new system.