Astronomers at the University of California, Irvine (UCI) have discovered a potentially habitable super-Earth located just 25 light-years away, offering a major new target in the search for alien life.

The newly discovered planet (GJ 3378b) orbits its host star (GJ 3378) within the coveted habitable zone and also happens to be a relatively close neighbor to us. Sure, 25 light-years may sound like quite the trek, but on the scale of our 100,000-light-year-wide Milky Way, 3378b resides practically next door.

Of course, what makes the planet particularly thrilling to scientists is its remarkable similarity in energy reception to Earth. 3378b has a minimum mass just over twice that of Earth and receives roughly 90% of solar radiation from its sun, thus placing the planet squarely in the goldilocks sweet spot for habitability. The team was able to detect the world by combing data from the Habitable-zone Planet Finder on the Hobby-Eberly Telescope in Texas and the NEID Spectrometer on the WIYN Telescope in Arizona.

Artist's conception of the surface of the habitable-zone super-Earth GJ 3378b. (Credit: Nikolai Berman / UC Irvine)

However, the all-important question arises: does GJ 3378b actually have an atmosphere that sustains life? The planet happens also to rest precariously on the edge of what astronomers have come to call the cosmic shoreline, which is the dividing line where a star's harsh radiation either strips a planet's atmosphere away or allows it to persist. In our solar system, Mars fell victim to this atmospheric stripping, leaving it a cold, barren desert.

If GJ 3378b managed to hold onto its gases, its atmosphere could be the perfect thickness to stabilize surface pressure and shelter liquid water. Paul Robertson, a UCI associate professor of astronomy and lead author of the study, noted that if you scaled the Earth down to the size of an apple, its atmosphere would only be as thick as the apple's skin—just enough to keep air breathable and shield against space.

Confirming the existence of this atmosphere will require a bit of patience. The UCI team is pinning its hopes on the next generation of space technology, specifically NASA’s planned Habitable Worlds Observatory, which is slated to launch sometime in the 2040s. This advanced telescope will be capable of directly imaging planets like GJ 3378b, allowing scientists to analyze its chemical composition and hunt for crucial biosignatures. According to UCI student Gogod James, who helped characterize the planet: "If a planet in the habitable zone has a proper atmosphere, we can justify further research looking for biosignatures, liquid water or other signs of life."

Main image credit: NASA

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