The Search for Earth Look-Alikes Is Getting Serious

Updated at 5:30 p.m. ET on March 29, 2023.

Several years ago, astronomers pointed a telescope at another star and discovered something remarkable: seven planets, each one about the same size as Earth. The planets were quite close to their small star—all seven of their orbits would fit inside Mercury’s. And yet, because this star is smaller, cooler, and dimmer than our own, at least three of those rocky worlds are in the habitable zone, at the right temperature for liquid, flowing water. Earthlike size and sunniness don’t guarantee that you’ll find ET, but if you were looking for signs of alien life beyond this solar system, this corner of the universe would be a promising place to start.

The system, which in telescope data. Artists at NASA have them, their imaginations guided by details of the worlds in our system, including Earth’s clouds and oceans, but the exoplanets have fundamentally remained a mystery. So when the James Webb Space Telescope, the newest and most powerful telescope out there, was launched, experts and space enthusiasts alike were anxious to point it toward this cosmic alphabet and get a real glimpse of the worlds within.