Scientists have narrowed the search for alien life to 45 worlds

Space · Published 24 October 2026 Swipe more like this →

In short: Out of over 6,000 known exoplanets, astronomers have identified a tiny fraction that could actually host life. By filtering for rocky surfaces and specific temperature ranges, researchers have created a high-priority map of the cosmos, pinpointing where we might finally find a second home.

To find life beyond our solar system, scientists use the Earth Similarity Index. This metric scores planets from 0.0 to 1.0 based on parameters like atmospheric pressure, temperature, and overall habitability. A score of 0.8 or higher indicates a planet that mirrors Earth in nearly every significant way. This systematic approach allows researchers to move beyond random discovery toward a focused search for 'Earth 2.0.'

Recent data from the ESA’s Gaia mission and NASA archives have allowed astronomers to filter thousands of exoplanets down to fewer than 50 rocky worlds. These candidates reside in the 'habitable zone'—the orbital region where a star's energy is balanced enough to allow liquid water to exist on a planet's surface. While water is the primary benchmark for life as we know it, the study also looks for planets receiving stellar energy levels similar to Earth's.

One standout candidate is Teegarden b, a 'super Earth' located just 12.4 light-years away. It orbits an M-type red dwarf star every 4.9 days. Despite possessing a surface temperature of roughly 2,700°C and weighing only a tenth of our sun, this star generates enough warmth to sustain its planets. Teegarden b is considered particularly promising because it sits in the habitable zone and is only slightly more massive than Earth.

The research, led by Professor Lisa Kaltenegger of the Carl Sagan Institute, also identified 24 planets within a more restrictive 3D habitable zone. This more rigorous classification measures the thermal limits a planet must endure to remain capable of supporting life. Notable targets in this list include Proxima Centauri b, TRAPPIST-1f, and Kepler 186f, providing a roadmap for future interstellar exploration.

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