Board Thread:Speculation House/@comment-3257939-20151009080148/@comment-24891101-20151011021519

Live: It cannot but be like Earth.

From visual examination, gravity looks to be very similar to Earth, because otherwise it'd look very different to us. Things would fall at rates we are not used to, and we'd have noticed.

Similarly, rocky planets must be within a particular temperature, density, and size range to allow for atmosphere retention. Since humans (and other familiar lifeforms) exist on the planet, we know that the atmosphere contains oxygen, water vapor (since it rains), carbon dioxide, and presumably nitrogen. This means that for a given temperature range (again, based on the life seen there), that the size and density are within certain ranges, to prevent gas escape. Observe. This tool is slightly disappointing on account of forbidding higher densities, but realistic in that those are unlikely. The interpretation of this is that the location of the planet on the graph must fall above the lines from the gases in order to retain that gas. For other densities, see the wiki article on escape velocity.

Moreover, the physiology of the life forms we've seen indicates that they exist in an Earth-like gravity, otherwise they would look very different.