I was taught years ago that one of the many conditions that make the Earth stable enough for complex life is that our “big brother” Jupiter works as a vacuum cleaner, clearing out wayward comets and asteroids from the inner solar system so fewer of them have a chance to contact Earth. Makes sense, Jupiter is big.
I recently learned, however, that Jupiter’s “surface gravity” is only 2.5x that of the Earth. No offense to Jupiter, but that feels less like a Kirby and more like a Swiffer.
Is there some different measurement of gravity (other than “surface gravity) that I’m not aware of that’s doing the heavy lifting? Or is it possible that in another, hypothetically similar solar system, a rocky planet 2.5x the size of earth positioned roughly the same distance Jupiter is from Earth would do the same “vacuuming” work?
In: 1661
The **surface gravity** of Jupiter is hard to guess, as it is a gas planet.
Its [mass is 318 times that of earth](https://solarsystem.nasa.gov/planets/jupiter/in-depth/), so its gravity would be 318 times more than earth’s. (assuming gravitational effects are linear with total mass and no weird quantum stuff going on at high mass.)
It is also much bigger in volume (say the difference between cleaning with a Q-tip vs a Swiffer) but in the vastness of space this is barely noticeable. Jupiter is 11 times wider than Earth.
Gravitational attraction is “inversely proportional to the square of the distance between objects”. That means that things getting close to Jupiter (but still far from the sun) **will have Jupiter be the largest gravitational force acting on it**.
The 4 inner planets have very close orbits to the sun, and then Jupiter is very far out. This gives Jupiter a large range of space where it is the biggest local gravitational effect. One sign of this is that Jupiter has 80 moons. (It also has rings discovered in 1979)
Latest Answers