- #1

- 20

- 0

Hello,

My girlfriend asked me this question - how far from earth do you have to be before you don't really feel any gravity from it anymore?

I suppose the question to ask is - how negligible does 'don't really feel' actually mean ...

After a bit of thought I think one way of defining this might be ...

If you could build a static platform at any distance you like from the center of the earth (that is not in orbit, but hangs there as the earth spins beneath), how far away from the center of the earth would it have to be before you could jump, using purely the power of your own legs to reach escape velocity?

Some further definitions.

The power of the jump is sufficient to allow the jumper to jump to a height of 1 meter when on the earths surface.

I think that should be enough to work it out ... if not please feel free to include other assumptions you had to make in your replies.

I'm also very interested to know how much the strength of the jump effects how far away you have to be to reach escape velocity - for example, if the jump is only good enough to reach a height of half a meter at the earths surface - what does this change the required distance from the center of the earth to? What is the equation for this in terms of

d = f(x)

where d = distance from the center of the earth before you can reach escape velocity and x = height jumped to on earths surface

If the value of x within a reasonable range radically changes the distance d then this is not a very good way to answer the original question which was ...

Alan

My girlfriend asked me this question - how far from earth do you have to be before you don't really feel any gravity from it anymore?

I suppose the question to ask is - how negligible does 'don't really feel' actually mean ...

After a bit of thought I think one way of defining this might be ...

If you could build a static platform at any distance you like from the center of the earth (that is not in orbit, but hangs there as the earth spins beneath), how far away from the center of the earth would it have to be before you could jump, using purely the power of your own legs to reach escape velocity?

Some further definitions.

The power of the jump is sufficient to allow the jumper to jump to a height of 1 meter when on the earths surface.

I think that should be enough to work it out ... if not please feel free to include other assumptions you had to make in your replies.

I'm also very interested to know how much the strength of the jump effects how far away you have to be to reach escape velocity - for example, if the jump is only good enough to reach a height of half a meter at the earths surface - what does this change the required distance from the center of the earth to? What is the equation for this in terms of

d = f(x)

where d = distance from the center of the earth before you can reach escape velocity and x = height jumped to on earths surface

If the value of x within a reasonable range radically changes the distance d then this is not a very good way to answer the original question which was ...

Is there a better way to define this question? - if so, what would that be, and more importantly - what is the ANSWER!!?how far from earth do you have to be before you don't really feel any gravity from it anymore?

Alan

Last edited: