A science question about mavity

SkScotchegg

SkScotchegg

SkScotchegg

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Hey there, I watched a new BBC documentary on Iplayer other night and it made me think of a question, it was all about equations but they talked about mavity and the universe and anyways my question is, how big does an object floating in space have to be to have a strong enough gravitational pull on an object the size of a football?

I hope am asking this question clear enough, I was just wondering like would it take an object the size of a car to make an object the size of a football orbit it with mavity or would you need an object the size of a football stadium to make an object the size of a football orbit it?

Just found this interesting, I like to know little facts like that so perhaps someone could explain the figures if there's some sort of calculation behind this?

Thanks in advance and merry christmas lol :D
 
Seem to remember that the force of mavity never quite dissipates over distance, so if you had just two atoms, on opposite sides of the universe, eventually they would be orbiting each other.

Or something.

So some random atom impossibly far away would have a pull on your football.
 
^^ Can be any size yeah. A black hole's centre is a singularity and is so massive that not even light can escape, for example!
 
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Oh thanks for your replies, I think am starting to understand. This is cool stuff haha.

Oh but wait a second, someone of you said its not to do with size, but in those BBC documentaries it says the scientist said that because Jupiter is so big it has a stronger gravitational pull then earth and pulls asteroids in towards it and they impact on Jupiter instead of earth and in a way Jupiter is sort of like a forcefield for earth and if Jupiter wasn't there we would have got hit by huge asteroids allot more often.

But then again, I guess coz its bigger it probably has more mass so I guess that's why.
 
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SkScotchegg said:
Well what mass would an object have to be to be able to make another object the size of a football orbit it in space?
Click to expand...
the mass of a football*

and any size IF there were nothing else acting upon it, two footballs would orbit around each other.
 
SkScotchegg said:
Hey there, I watched a new BBC documentary on Iplayer other night and it made me think of a question, it was all about equations but they talked about mavity and the universe and anyways my question is, how big does an object floating in space have to be to have a strong enough gravitational pull on an object the size of a football?

I hope am asking this question clear enough, I was just wondering like would it take an object the size of a car to make an object the size of a football orbit it with mavity or would you need an object the size of a football stadium to make an object the size of a football orbit it?

Just found this interesting, I like to know little facts like that so perhaps someone could explain the figures if there's some sort of calculation behind this?

Thanks in advance and merry christmas lol :D
Click to expand...

Don't forget that the football will also have gravitational pull on the object its orbiting. Any object with greater mass than the football reguardless of size.
 
F = GMm/r^2 will give you the force the two objects experience. You can combine that with some orbital formula that I forget, and it'll give you the radius at which the two will merrily orbit one another.
 
I cant imagine astronauts being good at football, as soon as one of them misses a pass that balls gone, no kids to run and fetch it up there.
 
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