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Question about gravity.

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wesmontfan
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26 Dec 2009, 8:42 pm

No, you cant 'use up' gravity if thats what you are asking.

Do a thought experiment.

The Moon is 1.25 percent the mass of the Earth.

If the Moon started to grow and gain mass magically it would still orbit the earth.

As it aproached the earths mass it would start to influence the Earth and jerk the earth around as it orbited the earth.

When it reached parity with the Earth's mass the two bodies would orbit around a common center halfway between them.

Then if the Moon continued to grow it would over power the Earth and finally the roles would reverse and Earth would become the sattelite of the might moon.

But earth's gravity would still effect the moon by creating tides on the moon like the moon now effects the earth so earth's gravity would not cease to teffect the moon.



ruveyn
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27 Dec 2009, 10:14 am

wesmontfan wrote:
No, you cant 'use up' gravity if thats what you are asking.

Do a thought experiment.

The Moon is 1.25 percent the mass of the Earth.

If the Moon started to grow and gain mass magically it would still orbit the earth.

As it aproached the earths mass it would start to influence the Earth and jerk the earth around as it orbited the earth.

When it reached parity with the Earth's mass the two bodies would orbit around a common center halfway between them.

Then if the Moon continued to grow it would over power the Earth and finally the roles would reverse and Earth would become the sattelite of the might moon.

But earth's gravity would still effect the moon by creating tides on the moon like the moon now effects the earth so earth's gravity would not cease to teffect the moon.



Isaac Newton made that point back in 1686. I am glad to see you have caught up.

ruveyn



wesmontfan
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27 Dec 2009, 11:41 am

ruveyn wrote:
wesmontfan wrote:
No, you cant 'use up' gravity if thats what you are asking.

Do a thought experiment.

The Moon is 1.25 percent the mass of the Earth.

If the Moon started to grow and gain mass magically it would still orbit the earth.

As it aproached the earths mass it would start to influence the Earth and jerk the earth around as it orbited the earth.

When it reached parity with the Earth's mass the two bodies would orbit around a common center halfway between them.

Then if the Moon continued to grow it would over power the Earth and finally the roles would reverse and Earth would become the sattelite of the might moon.

But earth's gravity would still effect the moon by creating tides on the moon like the moon now effects the earth so earth's gravity would not cease to teffect the moon.



Isaac Newton made that point back in 1686. I am glad to see you have caught up.

Huh?
Thats exactly the point!
I was addressing the original post of the thread in which the poster was asking (or seem to be asking) a basic question which needed to be answered in a simple basic way.
Everyone else is running when they shoulda helped the poster walk first1

I guess posting out of order confuses you.

I'll try not to be so .. confusing.. next time!
Jeeez



ruveyn



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27 Dec 2009, 4:59 pm

Posting out of order I can handle.

Typing out of order, so that what you say comes up in the middle of the post you're quoting - now that confuses me! :)


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justMax
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29 Dec 2009, 5:03 pm

Feynman gave my favorite explanation.

If you drew a circle around the Earth and measured the circumference of that circle, I like to have people imagine it going from one shoulder, all the way around the planet, back to their other shoulder... if you then measured the radius to the center of the Earth, it would be greater than you would expect geometrically.

There is a bit of excess radius in a region of curved spacetime, it is deeper towards the center of the Earth, and thus easier to move that way, than a different direction.


Oh, and anti-particles show no significant deflection in their behavior as would be expected if they were negatively charged gravitationally... unless you look at them the other way in time, at which point they interact normally, besides falling away from massive objects, where positively charged matter interacts oddly, but falls away as well.