# Scientists Find 45 Rocky Planets That Could Support Alien Life
Astronomers have created a comprehensive list of planets outside our solar system that might be able to support life. Using data from NASA's Exoplanet Archive and the Gaia spacecraft, researchers identified 45 rocky planets located in what scientists call the habitable zone.
The habitable zone is the orbital distance from a star where temperatures would allow liquid water to exist on a planet's surface. Liquid water is considered essential for life as we know it. Think of it as a Goldilocks zone: not too hot, not too cold, but just right.
Scientists examined over 6,000 known exoplanets, which are planets orbiting stars other than our Sun, to create this list. To qualify as potentially habitable, planets needed to be rocky like Earth rather than gaseous like Jupiter, and orbit within their star's habitable zone. The researchers set a size limit of 2 Earth radii or a mass limit of 5 Earth masses to identify rocky worlds. Earth radii and Earth masses are measurements that compare a planet's size and weight to our own planet.
Of the 45 candidates in the broader habitable zone, 27 pass in front of their stars from our viewpoint, making them easier to study through a method called transit observation. The team also identified 24 planets in a narrower, more conservative habitable zone definition based on sophisticated 3D climate models. These computer models simulate how atmospheres and weather patterns work on distant planets.
This catalog will help scientists prioritize which planets to study using powerful telescopes like the James Webb Space Telescope, the upcoming Extremely Large Telescope, and the future Habitable Worlds Observatory. Some planets orbit near the edges of the habitable zone, while others receive similar amounts of starlight as Earth does from our Sun. The researchers also identified planets with highly elliptical orbits, meaning they follow oval-shaped paths that bring them closer and farther from their stars. By studying these worlds, astronomers can test the limits of where life might exist and develop better strategies for finding extraterrestrial life.