Scientists Discover First Atmosphere on Earth-Like Planet in Habitable Zone

Astronomers have announced a groundbreaking discovery: the detection of the first atmosphere on an Earth-like, rocky exoplanet situated within the habitable zone of its star. The planet, designated LHS 1140 b, orbits a small red dwarf star approximately 48 light-years away from Earth. This milestone marks a significant step in the ongoing quest for extraterrestrial life, confirming that such potentially habitable worlds can retain protective gaseous envelopes.

The atmosphere was confirmed by detecting helium escaping from LHS 1140 b in 2024, utilizing the WINERED spectrograph on the Magellan Clay telescope. Researchers, including a team led by Harvard University's Collin Cherubim, found that the planet is roughly 5.6 times the mass and 1.7 times the radius of Earth, consistent with a rocky composition. The presence of an atmosphere is considered crucial for habitability, as it can stabilize surface temperatures, allow for liquid water, and shield a planet from harmful radiation.

This discovery challenges previous assumptions about planets orbiting active red dwarf stars, which are often thought to strip away planetary atmospheres due to intense radiation. LHS 1140 b's ability to retain its atmosphere for billions of years suggests that rocky exoplanets in these systems could be viable candidates in the search for life, despite being tidally locked to their stars.