Topline
Estimates on the mass of a nearby planet have been nearly cut in half, based on a study published in The Astrophysical Journal on Tuesday, making it a more plausible home for liquid water and even life than previously believed.
A person takes a photo with a camera on a tripod of the Milky Way at Nallihan district, in Ankara, on August 12, 2020.
Photo by Adem ALTAN / AFP
Key Facts
The study estimated the mass of GJ 3378b, a rocky planet 25 light-years from Earth, at about 2.3 times that of Earth, according to the McDonald Observatory, a significant departure from earlier estimates of five times the Earth’s mass.
That level would still be unforgiving for a human body, but makes it more likely the planet is rocky and does not have the crushing atmosphere that would make liquid water and surface life impossible, according to the scientists involved with the study.
Scientists also believe the planet’s orbit makes a 21-day loop around its star and receives nearly the same amount of starlight as Earth, according to the McDonald Observatory, which confirmed the planet is in the “habitable zone.”
The planet “brings us one step closer to knowing all of our neighbors and, ultimately, which might be hospitable for life,” University of Texas at Austin astronomer Michael Endl said about GJ 3378b.
Contra
Some of GJ 3378b’s conditions point away from the planet being suitable for sustaining life. The planet’s close orbit around a star may expose it to “intense radiation” that could strip away any atmosphere, though researchers note further observations are needed to be more certain.
What To Watch For
Whether GJ 3378b is able to maintain an atmosphere despite its radiation threat. Space observation facilities on Earth such as the Giant Magellan Telescope, Extremely Large Telescope and Habitable Worlds Observatory are expected to begin operations in the coming years and could scan GJ 3378b directly for signs of life.
Key Background
GJ 3378b, which has been nicknamed as “Super-Earth” because of signs of a rocky surface and relatively similar atmosphere, was first identified in 2024 orbiting a red dwarf—a small, cool star roughly one-third the size of the sun. Red dwarfs make up around 70% of all stars in the Milky Way and are the most common place to look for life-supporting planets. Paul Robertson, the lead author of the study published Tuesday, said his team’s guiding principle is rooted in a mantra: “follow the water.” He added water is “the one thing every known living thing on Earth needs, so that’s the first thing we look for when trying to find environments that could sustain life.”
Further Reading
Nearby “Super Earth” May Be a Better Candidate for Life Than Previously Thought (McDonald Observatory)