Talk:TRAPPIST-1c

Relationship Between Planet Atmosphere and Density of Planet

Under the 'Mass, radius, and temperature' subsection, it is claimed that, "Despite its Earth-like mass and radius, TRAPPIST-1c has a lower density (4.89 g/cm3) and gravity (0.966g) than Earth. This is consistent with a rock-based composition and a thick, Venus-like atmosphere, similar to TRAPPIST-1b." The problem with that claim is that even if the Earth suddenly acquired a Venus-like atmosphere, one 7.4 kilometres (15.9km-8.5km) thicker than it currently has, it would still have almost exactly the same density (5.51 g/cm3) and gravity (1.0g) as it currently has, under an Earth-like atmosphere. You would need a much, very much, thicker atmosphere than that of Venus, hundreds of kilometres thicker, to have a significant impact on the density of the planet, if its density is simply calculated from its observed radius and measured mass. The paper quoted to back up the claim in the subsection isn't using Trappist-1c's lower density compared to that of Earth's as proof it has a Venus-like atmosphere. It is just simply saying that its density is entirely consistent with that of it having a Venus like atmosphere, which I assume they believe is a possibility since its temperature is higher compared to Earth's and so has quite possibly gone through a runaway greenhouse effect. 217.44.196.245 (talk) 22:35, 19 December 2022 (UTC)