TRAPPIST-1 Planets Have Atmospheres Which Could Support Life
TRAPPIST-1 is a small red dwarf star about 40 lightyears from our sun, but the planets orbiting around it have always been more significant: all seven of those planets are close to Earth's size and have the potential to contain liquid water, and it's thought that some of them (or possibly all of them) could support life.
Now we have a much better idea of just how well these far-off exoplanets would support life. According to a new study published in Proceedings of the National Academy of Sciences, all seven planets could possibly have a stable atmosphere despite tough conditions caused by their star, and the outermost planets in the solar system almost certainly have intact atmospheres.
Previously, it was thought that despite the planets being so Earth-like, the TRAPPIST-1 star itself complicated things by being far more active than our own sun, and prone to solar flares and stellar winds which could easily reach out millions of miles to where those defenseless planets are sitting.
Those winds and flares of solar activity could easily blow out a planet's atmosphere, but the study examined each of the planets' chances of retaining an atmosphere, and concluded their odds were better than anyone had assumed upon first discovering the planets.
Of course, now we're getting into "never tell me the odds" territory. This doesn't mean that all of the planets have atmospheres, just that each of them potentially could. The outermost planets have the best chances, being far away enough from the star that they're not too impacted by all the solar troubles.
These outermost planets are designated as TRAPPIST-1g and TRAPPIST-1h (with -1b through -1f having weaker, but still non-zero chances), with the former planet, -1g, being the most interesting. Because alongside its high likelihood of holding onto an atmosphere, it's one of the three planets in that solar system's habitable zone (which includes -1e, -1f and -1g).
Those two factors make -1g the most likely planet in the system to contain liquid water on its surface, and enough of it to be capable of supporting life. If we could only visit one planet in the system, this would be the one, and as more powerful telescopes like NASA's upcoming James Webb Space Telescope come along, they'll start pointing that way.
NASA (@NASA) February 22, 2017
Although, if we actually could visit one of these planets, it would be especially easy to go see the others. All the planets around TRAPPIST-1 are packed so close together, that if you stood on the surface of one planet, you could easily see the remaining planets filling up the sky.
So it would take a lot of work, and at least a few major advancements in the field of astrophysics, but eventually, we could have up to an entire solar system of planets to colonize (assuming there's nobody there already). Or at the very least, we'd have two planets within cosmic spitting distance of each other.