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Author Topic: Why is it that the pool balls?  (Read 6655 times)

infringement153

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Why is it that the pool balls?
« on: May 29, 2010, 08:56:47 PM »
Ok, I don't know much about Newtonian gravity, but I do know that the force between pool balls isn't enough to pull them back together (at least not if you don't leave them there for an eternity).  Why is it that these pound-weighing objects come back together?  Same goes for the soccer ball orbiting the 9-pound bowling ball.

Naru523

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Re: Why is it that the pool balls?
« Reply #1 on: May 29, 2010, 09:59:42 PM »
They have mass. Everything has mass; but some objects are attracted to the Earth, so we can't feel it. If it was in space with no larger object nearby, it would make its own gravity now.

Laura

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Re: Why is it that the pool balls?
« Reply #2 on: May 30, 2010, 05:43:07 AM »
For such microgravity to take over, one must be sure to find a flat region of space. It couldn't be done in Earth orbit, for example, since the hill sphere of the Earth would prevent the pool balls from orbiting each other, instead making them all orbit Earth. The mass of a pool ball is so small that its own hill sphere is beneath the surface, so it can't retain a satellite if inside the hill sphere of another object.

infringement153

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Re: Why is it that the pool balls?
« Reply #3 on: May 30, 2010, 05:50:54 PM »
So the simulations in US2 with the balls orbiting the bowling ball portrays a speed in which it would be possible for the balls to orbit without getting flung out by centripetal force, assuming you isolated it from the rest of the universe?
« Last Edit: May 30, 2010, 05:58:05 PM by infringement153 »

Laura

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Re: Why is it that the pool balls?
« Reply #4 on: May 30, 2010, 08:50:05 PM »
So the simulations in US2 with the balls orbiting the bowling ball portrays a speed in which it would be possible for the balls to orbit without getting flung out by centripetal force, assuming you isolated it from the rest of the universe?

Pretty much. It should work well away from gravity wells. Interstellar space would do the trick :)

infringement153

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Re: Why is it that the pool balls?
« Reply #5 on: May 30, 2010, 09:06:32 PM »
So the simulations in US2 with the balls orbiting the bowling ball portrays a speed in which it would be possible for the balls to orbit without getting flung out by centripetal force, assuming you isolated it from the rest of the universe?

Pretty much. It should work well away from gravity wells. Interstellar space would do the trick :)

Now I really want to go to interstellar space.

But wait, that'd mean they'd orbit around me...and my wife would become even more attracted to me, so to speak.
« Last Edit: May 30, 2010, 09:25:31 PM by infringement153 »

Laura

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Re: Why is it that the pool balls?
« Reply #6 on: May 30, 2010, 10:01:45 PM »
So the simulations in US2 with the balls orbiting the bowling ball portrays a speed in which it would be possible for the balls to orbit without getting flung out by centripetal force, assuming you isolated it from the rest of the universe?

Pretty much. It should work well away from gravity wells. Interstellar space would do the trick :)

Now I really want to go to interstellar space.

But wait, that'd mean they'd orbit around me...and my wife would become even more attracted to me, so to speak.

Well, you could orbit each other :)
The problem is that you'd be in a spacecraft with much more mass than you.

Dan Dixon

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Re: Why is it that the pool balls?
« Reply #7 on: June 03, 2010, 12:03:35 AM »
So the simulations in US2 with the balls orbiting the bowling ball portrays a speed in which it would be possible for the balls to orbit without getting flung out by centripetal force, assuming you isolated it from the rest of the universe?

Pretty much. It should work well away from gravity wells. Interstellar space would do the trick :)

This is my understanding as well. Notice how slowly everything is moving in the pool ball or small scale gravity simulations. So slow that in real time mode you can't even tell they are moving.
« Last Edit: June 03, 2010, 01:39:40 PM by Dan Dixon »

atomic7732

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Re: Why is it that the pool balls?
« Reply #8 on: June 03, 2010, 10:52:34 AM »
It takes 8 hours for one of the inner objects on the small scale gravity with bowling ball.