NASA
The outer planets of the TRAPPIST-1 system might be better for life than we thought. Their cores are stretched by gravity, which generates heat, and there’s a possibility these exoplanets have atmospheres, so the outermost planets could be warmer and wetter than we thought, maybe even with air.
We have very little data on the TRAPPIST-1 planets. We know their distances from their star and one another, and their approximate sizes and masses. Based on this limited information, Amy Barr at the Planetary Science Institute in Tucson, Arizona estimated the distribution of four materials – iron, rock, ice, and liquid water – within each planet. They also examined whether tidal forces could stretch and flex the planets’ cores enough to heat them from the inside.
They found that six of the seven planets have low enough densities to indicate the potential