Scientists are on the hunt for new worlds beyond our solar system—some of which could support alien life. To help, NASA recently launched a new satellite named TESS (short for Transiting Exoplanet Survey Satellite). It will search the stars for undiscovered exoplanets.
TESS uses four specialized cameras to document changes in the brightness of distant stars. Periodic dips could indicate the existence of an orbiting planet passing in front of the star. With the help of TESS’s images and telescopes on Earth, scientists can then determine an exoplanet’s mass, size, and density (mass per unit volume).
“We are looking for rocky planets with an average density similar to Earth’s,” says Sara Seager, an astrophysicist at the Massachusetts Institute of Technology. If these planets occupy what’s called the habitable zone—the distance from a star at which liquid water can form—and have a protective atmosphere, it’s possible they could support life.