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Question about gravity.

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posted on Oct, 20 2012 @ 07:25 PM
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Originally posted by jiggerj
I have a question for you. In this image you have three masses made of the same materials within a vacuume space, but they are different in size. My question is. Which mass attracks which? Or do they stay in the same positions?
I would assume that the highest mass attracts the others.




All masses attract all masses. Some more than others.
They will end up (in a bunch) somewhat near the upper right side of the triangle, location biased towards the larger masses.



posted on Oct, 20 2012 @ 07:40 PM
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By the way.....even when astronauts are in the space station, and you see them floating around...they have gravity. The space station is in a vacuum as well. If there was no gravity in a vacuum, theyd fly off into space instead of being in orbit. Same for the moon.....and the earth would fly off from the sun too!

The floating astronauts float because theyre falling. They fall around the earth, not to it, because of altitude, speed, and trajectory. They also use nearly no fuel...no engines are running. Small boosters may fire occasionally to alter/correct its course.

And your weight is gonna hit the sides at some point. Magnets could be used to suspend it in the middle i suspect.

Why the north/south poles? how about from your house to china?



posted on Oct, 20 2012 @ 08:17 PM
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Originally posted by alfa1

Originally posted by jiggerj
I have a question for you. In this image you have three masses made of the same materials within a vacuume space, but they are different in size. My question is. Which mass attracks which? Or do they stay in the same positions?
I would assume that the highest mass attracts the others.




All masses attract all masses. Some more than others.
They will end up (in a bunch) somewhat near the upper right side of the triangle, location biased towards the larger masses.


Larger masses, or most concentrated masses? And, what does this have to do with something falling through the middle of the earth in a vacuum?



posted on Oct, 20 2012 @ 08:40 PM
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Originally posted by punkinworks10
reply to post by spy66
 


Spy, you are misunderstanding what a " vacuum" is.
A vacuum is an absence of gaseous phase matter, not an absence of all matter.
Like so many people have said it has no effect on the force of gravity, none what so ever.
And all mass has a gravitational field, very likely down to the quantum level, for those interested look into quantum gravity detection experiment being put together by Cal State Humbolt, fascinating stuff.
Anyhoo, Spy in your OP, the scenario you have works like this,
Your tunnel is a vacuum, the only effect it will have is an absence of media to provide friction, that's it ,it will not effect gravity at all.
So now , the force of gravity follows an inverse square relationship with distance from the center of mass, that is to say the force falls off at a rate that is proportional to the square of the distance between the objects.
That's why the acceleration due to gravity , which at the earths surface is 32/sec^2, falls off so quickly.
The weightless of " space" is not a gravityless environment, it is micro gravity environment, as long as there is mass there is gravity.
With all that in mind, if one were to drop your mass down the tunnel from the north to south pole, your mass would start with a specific amount of gravitation potential energy, it will accelerate at 32 feet/sec^2, to start with. It will change because the of the differing densities of the materials that make up the earth and their relative masses. But to keep it simple we will say it falls at a 32ft/sec^2. As it falls the gravitational potential energy is turned into kinetic energy, according to the equation U=mgh, where U is gravitational potential energy
m is mass, g, acceleration due to gravity 32ft/sec^2 and h is height of object or in this case the distance from the theoretical center of gravity.
Now a body in motion will stay in motion a body a rest will stay at rest, that is verbal expression of conservation of momentum. In absence of external forces acting on a moving body a moving body will stay in motion.
Back to the hole, your mass accelerates toward the centers of gravity, turning gravitational potential energy to kinetic energy. As it it approaches the center the force of gravity in front of it increases, because of the increasing density, but conversely as you pass through the earth all of the mass behind the falling mass has a gravitational effect on the motion of the moving mass slightly slowing it down.
This is where I differ from the poster who said, that in a vacuum, it would be a simple oscillation scenario and the mass would oscillate back and forth forever, it would not. If your are using the.force of gravity as a force in the analysis, you can't also discount it.
Classical newtonian physics treats the earth as a point mass, but if you are looking at the mass of the earth as as a system then you have have to account for the mass in relationship to the position of the object and differing forces of gravity due to changes in density as it moves through the gravitational system that is the earth as a whole. It would appear to follow a simple straight line oscillation back and forth losing energy and eventually settling and coming to rest at the bottom of the gravity well.
No it would follow a extremely eliptic path orbiting the theoretical center of gravity. This orbit would decay over time in to rotational motion of the original mass at the center of the earth.
So the mass would swing back and forth not going quite as far each trip and it would eventually come to rest at the center of the earth, spinning, at a very high rate it might add as momentum must be conserved.
All of the momentum of the original mass has to be maintained it is converted from linear momentum to rotational momentum.
This is why stars and planets rotate around thier own axes and why planets and asteroids and comets rotate around stars and why star systems orbit the center of the galaxy and galaxies orbit even larger groups of each other.


Outstanding post in such an....odd thread



posted on Oct, 20 2012 @ 09:04 PM
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reply to post by VoidHawk
 


Thank you VoidHawk,
I detect a Peter F Hamilton fan,

I think that as a sci fi writer Hamilton has done more to divine the path of future technology than any other writer in in the recent past.Some of the ideas he has posited in his books are aleeady coming to pass.



posted on Oct, 20 2012 @ 09:09 PM
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Originally posted by punkinworks10
reply to post by VoidHawk
 


Thank you VoidHawk,
I detect a Peter F Hamilton fan,

I think that as a sci fi writer Hamilton has done more to divine the path of future technology than any other writer in in the recent past.Some of the ideas he has posited in his books are aleeady coming to pass.



""I detect a Peter F Hamilton fan""
I'm still looking behind me, how did you know that?

ETA: stupid me....my name

Yes, fantastic stuff.

edit on 20-10-2012 by VoidHawk because: (no reason given)



posted on Oct, 20 2012 @ 09:19 PM
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reply to post by spy66
 





How can it be effected by earths gravity inside the vacuume tunnel


because you get gravity in a vacuum..



posted on Oct, 20 2012 @ 09:29 PM
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Originally posted by spy66

My question is:

If you built a vacuume tunnel that runs from the North pole throught earths center and to the South Pole. And on the North Pole you placed a 10kg weight into the vacuume tunnel. Would the weight fall/travel to the South Pole?

My teacher/Professor tells me that the 10kg weight would fall to the South Pole. I am telling him that the 10kg weight would not travel anywhere.

I have also googled this question and found that a lot of other people agree with my teacher. But they are all wrong. Does anybody here know why my teacher is wrong?





It would fall almost all the way through then return almost all the way back, losing some energy in the process until it would stabilize at the center.



posted on Oct, 20 2012 @ 09:36 PM
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reply to post by spy66
 


Better not tell the rest of the celestial bodies your theory. Anarchy on a universal scale.



posted on Oct, 20 2012 @ 10:37 PM
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Hi science fans !

Hey OP, give us a serious source where it is said that
== vacuum cancels anything but air/gaz friction ==

Vacuum CERTAINLY does NOT cancel gravity.
"Fast spinning" diminishes gravity.

Blue skies.



posted on Oct, 20 2012 @ 10:42 PM
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reply to post by spy66
 


The weight would travel to the centerline between both poles and suspend there.
At the center of gravity.

Hypothetically of course.



posted on Oct, 21 2012 @ 03:16 AM
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Originally posted by purplemer
reply to post by spy66
 





How can it be effected by earths gravity inside the vacuume tunnel


because you get gravity in a vacuum..


Ok. What is the weight of the vacuum column at earth's center? If there is gravity the vacuum column should have a specific weight. What is it?
edit on 27.06.08 by spy66 because: (no reason given)



posted on Oct, 21 2012 @ 03:26 AM
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a little off topic,,, but why is there little to no gravity at the center of earth? what creates gravity?



posted on Oct, 21 2012 @ 03:26 AM
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Originally posted by spy66
If there is gravity the vacuum column should have a specific weight.


Why do you think that?



posted on Oct, 21 2012 @ 03:52 AM
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reply to post by ImaFungi
 

Mass creates gravity. At center of mass of a body the gravity is zero because it is "canceled" by the surrounding mass. You are literally pulled in all directions with the same force magnitude. All physical forces have this property called superposition, means the resulting force is a sum of all forces.



posted on Oct, 21 2012 @ 05:05 AM
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reply to post by spy66
 


All matter has mass, and according to the theory of relativity, mass bends space and time to create gravity.

A vacuum is only void of matter, but it is not a void of space and time.

If you magically created a cylinder that passes through Earth from North to South, and you vacuumed out all the air and matter, there would still exist space and time throughout the cylinder.

All the matter of Earth, and the matter that creates the cylinder walls, has mass, and that mass still bends the space and time around it, so gravity still exists inside the cylinder.

It is the entire collection of atoms the make up the Earth which contributes to Earth's gravity. There is no magical device in the center of Earth that creates gravity and attracts everything. It is the body of Earth as a whole, every part of it, every atom, including you, which bends space and time and causes things to fall into this pit of space and time.

So, if you have an object at the North pole, and you are about to drop it down this magical cylinder, before you drop it understand that every single atom that Earth consists of is bending space and time below the object, and causing this object to fall into this pit of space and time.

When you drop the object, it will actually be "attracted" to the walls of the cylinder, because it is the mass surrounding the cylinder which is creating gravity.

As the object falls deeper into the center of Earth, and gets closer to the Southern hemisphere, it becomes more "attracted" to the Northern hemisphere, because more and more atoms that the Earth consists of are above the object, including you, on the Northern hemisphere. All of the mass which is above the object, including you, are bending space and time and causing the falling object to slow down. However since there is still more mass below the object, it is still falling, and gaining momentum.

By the time the object approaches the center of the Earth, the object will have enough momentum to continue past the center, but not by far, because it lost a lot of speed to do gravity from the North hemisphere. The object would then lose momentum, become less "attracted" to the South hemisphere and more "attracted" to the North hemisphere, and turn around, and start falling to the center again. Over time, the object would come to a rest in the center of the Earth. The object would never reach the South pole.

When the object is in the center of Earth, there is a lot of gravity. However, the gravity is coming from all directions. The gravity from the North hemisphere and the gravity from the South hemisphere would both be pulling the object in both directions somewhat equally, so there would be a neutral position in the center of Earth which would feel like zero gravity, even though there is a lot of gravity.

-note- When I say "attracted" I am referring to the illusion of an object being attracted like a magnet. In theory, gravity does not attract. Mass warps space and time, and objects fall into this warp, they are not attracted.

Disclaimer: I don't subscribe to the theory of relativity. I know of better theories. This explanation here is just a textbook explanation and does not represent my complete understanding and beliefs.
edit on 21-10-2012 by illuminated0ne because: (no reason given)



posted on Oct, 21 2012 @ 05:14 AM
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Originally posted by VoidHawk

Originally posted by punkinworks10
reply to post by VoidHawk
 


Thank you VoidHawk,
I detect a Peter F Hamilton fan,

I think that as a sci fi writer Hamilton has done more to divine the path of future technology than any other writer in in the recent past.Some of the ideas he has posited in his books are aleeady coming to pass.



""I detect a Peter F Hamilton fan""
I'm still looking behind me, how did you know that?

ETA: stupid me....my name

Yes, fantastic stuff.

edit on 20-10-2012 by VoidHawk because: (no reason given)


That makes three Peter F Hamilton fans on this thread :-)

If you like Peter F Hamilton try Neal Asher. Start with Grid-Linked and then onwards. Similar to the hamilton stuff but with a stronger undercurrent of jet black humour.



posted on Oct, 21 2012 @ 05:33 AM
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the object would stay in the center of the tube



posted on Oct, 21 2012 @ 05:38 AM
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reply to post by Razimus
 


That would only be true if the Earth was a perfect sphere, and has equal mass in all directions from it's center. More than likely the Earth is not perfect, so the object wouldn't remain perfectly in the center, but very near the center.



posted on Oct, 21 2012 @ 05:39 AM
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reply to post by Razimus
 


No it would not. To anyone interested into what would happen to the weight look here: en.wikipedia.org...



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