Re:Speculoos-2c: A new potentially habitable earth
by est31 on Wednesday September 07, 2022 @08:18AM
(#32749612)
> 36% larger radius than Earth means ~2.5x more volume. If it has a similar density to Earth 2.5g would probably stretch the definition of habitable for humans.
Volume scales cubically, yes. And therefore, also does the gravitational pull by the object at the same distance to the center. But due to the larger radius, you are also further away. Gravity respects the inverse square law. This means that the surface gravity of an object that maintains the same density increases linearly with the object's size.
In other words, you would have 1.36g on the planet's surface, not 2.5g. But that's assuming same density. Even within our own solar system this is not true: Mars's surface gravity is 0.38 of earth's gravity but 0.53 of earth's radius. The gravity is lower than it would be if Mars had the same density as earth.
Volume scales cubically, yes. And therefore, also does the gravitational pull by the object at the same distance to the center. But due to the larger radius, you are also further away. Gravity respects the inverse square law. This means that the surface gravity of an object that maintains the same density increases linearly with the object's size.
In other words, you would have 1.36g on the planet's surface, not 2.5g. But that's assuming same density. Even within our own solar system this is not true: Mars's surface gravity is 0.38 of earth's gravity but 0.53 of earth's radius. The gravity is lower than it would be if Mars had the same density as earth.