A rocky, Earth-sized planet in the Milky Way may have an atmosphere, raising hopes for the existence of liquid water and possibly life. This comes from new studies focusing on the TRAPPIST-1 system, which has seven rocky planets orbiting a single star. Researchers used NASA’s James Webb Space Telescope to examine one planet, TRAPPIST-1e, and found it might have a nitrogen-rich atmosphere, similar to Earth’s. However, more research is needed to confirm this.
These findings are critical in the quest for extraterrestrial life. Notably, NASA recently suggested that a sample from Mars could contain signs of ancient microbial life. While Mars today has a thin atmosphere, scientists believe it was once thicker and supported flowing liquid water.
Water is essential for life, making the hunt for exoplanet atmospheres vital. Ryan MacDonald, an exoplanet astronomer, stated, “We need to find planets with atmospheres first.” The TRAPPIST-1 system, located 40 light-years away, has been a focal point since 2016 for its potential to support life.
Specifically, TRAPPIST-1e is in the “habitable zone,” where conditions may allow liquid water to exist. Researchers observed the planet during four transits—moments when it passes in front of its star. While they didn’t see the atmosphere directly, they analyzed how the light was absorbed to infer its composition.
This technique is akin to using a prism, revealing which gases might be present based on the colors of light filtered out. So far, there are no signs of a hydrogen-rich atmosphere or excessive carbon dioxide. However, the hint of a nitrogen-rich atmosphere is exciting. Caroline Piaulet-Ghorayeb from the University of Chicago, who wasn’t involved in the studies, noted it narrows the possibilities for an Earth-like atmosphere on TRAPPIST-1e.
The nitrogen in Earth’s atmosphere is crucial for life, and other celestial bodies like Titan, Saturn’s moon, also have nitrogen atmospheres. Titan is intriguing because it potentially hosts vast underground oceans, even if its environment differs significantly from Earth’s.
Studying these planets is challenging. The TRAPPIST-1 star is small but highly active, adding background noise to the data. The scientists have spent over a year sifting through the Webb telescope’s observations to isolate the signals from TRAPPIST-1e itself.
Looking ahead, MacDonald and his team plan to study TRAPPIST-1e further during 15 more transits, along with three other planets in the system. Each study moves us closer to answering long-standing questions about the potential for life beyond our solar system.
Piaulet-Ghorayeb pointed out, “We haven’t convincingly found an atmosphere on any rocky planet outside our solar system, making this research thrilling. However, a lot remains to be done.”
As we delve deeper into the cosmos, each revelation brings us closer to understanding our place in the universe. For more on exoplanets and atmospheres, check out NASA’s official resources here.
