If an exoplanet like Kepler 442b, the most likely to be habitable exoplanet, has a mass 2.34x that of earth, would the gravity of the planet be 2.34x that of earth as well? Also, how would this affect humans if they were to travel there?

Question

If an exoplanet like Kepler 442b, the most likely to be habitable exoplanet, has a mass 2.34x that of earth, would the gravity of the planet be 2.34x that of earth as well? Also, how would this affect humans if they were to travel there?

In: Physics

Answer 1

Depends on the size of the planet. Gravity increases proportionately with mass but inversely proportionately with the square of the distance.

Consider the Moon. The mass is 0.0123x Earth, but its (equatorial) radius is 0.2725x Earth. Combining these gives us:

(0.0123/0.2725^(2)) = 0.1656… which is around 1/6th the gravity of Earth, which is what we observe.

So, if Kepler 442b was simply 2.34 the mass of Earth but also the same size then, yes, it would be 2.34x the gravity of Earth. But it’s radius is 1.34x Earth which gives us:

(2.34/1.34^(2)) = 1.3032… so it is about 30% more gravity than Earth.