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?
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The surface gravity is only 2.5 times the Earth’s, but remember that Jupiter is also way bigger. The strength of gravity decreases with the square of the distance, and Jupiter is 318 times Earth’s mass. This means that at three same distance from the center of both, Jupiter pulls on an object with 318 times the force, rather than the 2.5 times that surface gravity would suggest.
The gravitation on the surface depends on the distance from the center of the planet and has nothing to do with the gravitational effect the planet has in his system.
Jupiter is more than 317 times heavier than earth and because of this he attracts 317 times more the earth.
The gravitational acceleration on the surface of the sun is also only 30 times stronger that of the earth while the sun is 333.000 times heavier than the earth.
Jupiter is bigger, like, a lot bigger then earth, that size also expands, so the radius of earth is 6,371 km, while jupiter is 69,911 km, the moon is 384,400 km away from earth, while the farthest known moon from jupiter is Kore which is 23,239,000 km from jupiter.
Thats really it, jupiter is just massive.
I dont know why we’re think 2.5x gravity is small either. I’d weigh 375lbs on Jupiter
I’d be crushed. It’s a crushing amount of gravity…
As there are already good answers, I hope a tangent is okay.
I occasionally see questions like “If a black hole were to pass near the Solar System, how could we avoid falling into it?” or “If most galaxies have a giant black hole at their core, why haven’t they already swallowed everything?” I am reminded of such questions because this one shows the same misunderstanding in reverse. Gravity at the ‘surface’ of a black hole is effectively infinite, but that only matters if you’re near the surface.
To the first of the questions I quoted, the answer is: same way we avoid falling into the Sun, but easier (even though, according to current theory, the smallest black hole is more than twice as massive as Sol) because it is a much smaller target. (But see Greg Egan’s short novel *Perihelion Summer* for a better reason to be afraid.)
To the second: the core singularity is huge, yes, but it’s also very far from us.
Jupiter formed before the sun ignited, and during that time it was spiraling into the inner solar system preventing the formation of a planet at the asteroid belt with material getting pushed out of orbit, it similarly affected the formation of Mars which actually should have been bigger than Earth. Only the formation of Saturn pulled Jupiter back out of the inner solar system in its beginning.
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