What is neptunes average mass?
1) “Neptune is a comparatively small planet for our solar system with an average mass of 102.43×10^24 kg and an average diameter of 49,572 km. It is roughly 388% the size of the planet Earth.” Source and further information: http://www.absoluteastronomy.com/planets/Neptune.htm 2) I had some problem to understand what is meant with “average mass”. The point is that the mass of a planet can only be determined using some measurements of its gravity, and that different measurements could produce different results. Here some information about the measurement of the mass of a planet: “The only way we can measure a planet’s mass is through its gravity. This has been the way Earth’s mass was measured, too (we can’t directly probe what’s in Earth’s interior, but we can measure the gravity on the surface). Since nobody ever visited other planets and was able to measure gravity on the spot, we usually have to resort to other methods.
