Exoplanets
A decision brief on what we know, what comes next, and how to support the search for other worlds.
An exoplanet is any planet beyond our solar system. Most orbit other stars. Some are free-floating “rogue planets,” untethered to any star.
Scale changes the question
6,000
confirmed exoplanets, and counting.
NASA’s milestone arrives just over 30 years after the first exoplanets were found. Thousands more candidates await confirmation.
Not one kind of world
Size and mass reveal a remarkable range of compositions.
01
Gas giant
Large, gas-rich planets like Jupiter and Saturn.
02
Neptunian
A category that includes smaller, gas-rich worlds.
03
Super-Earth
Worlds larger than Earth, with varied compositions.
04
Terrestrial
Rocky planets, alongside worlds dominated by water, ice, iron, or carbon.
Observed extremes include lava worlds, puffy planets with the density of Styrofoam, and dense planetary cores.
The habitable zone is a filter, not a verdict
The area around a star where a planet could have liquid water on its surface.
Why search?
Whether life exists beyond Earth is one of the most profound questions of all time. The answer, whatever it is, will change us forever.
A habitable-zone location is a starting point for study. It does not establish that a planet is habitable or inhabited.
Distance makes observation the strategy
1
Transit: watch a planet pass in front of its star and measure the dip in light.
2
Wobble: detect the star’s motion caused by an orbiting planet.
3
Coronagraph: block a star’s intense light to reveal smaller, dimmer planets nearby.
Nearest known example
4 light-years
Proxima Centauri b is still about 4 light-years away. One light-year equals 5.88 trillion miles, or 9.46 trillion kilometers.
Roman expands the observatory toolkit
NASA’s Nancy Grace Roman Space Telescope is scheduled to launch Aug. 30, 2026.
Launch
Begin a new spaceborne observatory mission.
Coronagraph
Test technology that blocks starlight.
Panoramas
Create enormous views of the cosmos.
Discovery
Study exoplanets and planet-forming disks.
Instrument note
A grand-piano-sized starlight blocker
The Roman coronagraph is one of the most complex optical instruments ever built. It will help demonstrate direct-imaging capabilities for future missions.
The mission is also designed to address essential questions about dark energy and astrophysics.
Public value sits in the data infrastructure
Catalog
A continuously updated reference
More than 6,000 confirmed planets, with descriptions, vital statistics, 3D models, and filters by type, discovery method, spacecraft, observatory, or facility.
Participation
Citizen science widens the search
NASA welcomes the public to sift through data. Volunteers have contributed to thousands of important discoveries.
Targeting
Prioritize nearby stars
The Target Star Catalog guides future missions seeking Earth-like exoplanets and signs of life. About 75 percent of stars in the Milky Way are red dwarfs.
The field has grown through spacecraft, ground observatories, improved detection methods, and public engagement.
Recommendation
Treat exoplanet science as a long-horizon public capability, not a one-time milestone.
A
Invest in open, durable data access. Support catalogs, standards, visualization, and public interpretation.
B
Build participation into the program. Connect researchers, educators, and citizen scientists to usable datasets.
C
Plan for technology succession. Use Roman’s coronagraph demonstration to inform future searches for habitable worlds.
Decision lens
Fund the system around discovery.
Confirmed planets are the visible output. The durable public value is the capability to find, compare, explain, and responsibly pursue the next ones.