Question about gravity.

reply to post by ImaFungi

a little off topic,,, but why is there little to no gravity at the center of earth? what creates gravity?

The gravity on one side of the Earth balances the gravity from the other side of the Earth. The total or net force is zero.

reply to post by SplitInfinity

Sorry...but what you post is not true. Even if you had a way of having a Pendulum swing in a Vacuum and with ZERO FRICTION of any Mechanical Movement...it would still come to rest from swinging due to Gravity.
THAT IS A FACT! Split Infinity

Assuming that gravity always manifests the same force given the same conditions, the frictionless pendulum would swing forever.

For each swing, the force accerlerating the pendulum down exactly equals the force slowing the pendulum up.

Everytime.

reply to post by illuminated0ne


Although the part of the Earth above the falling object is exerting gravitational force against falling; the part of the Earth below the falling object is larger until center, and exerts more force per pound (more g's) as it is closer.

reply to post by SplitInfinity


Gravity is.

"The earlier scientists thought that the planets were propelled trough space by the fairies beating their wings. This theory has since been modified......" Richard Feynman

reply to post by SplitInfinity

If you adhere to Warping of Space/Time then Gravity is an effect that is changing the Geometry of Distance

According to Relativity

Gravity would be the result, not the cause, of space time warping. Mass warps the space and gravity is the effect

All straight lines in space terminate at a mass, unless there is a symetrically placed mass.

reply to post by Semicollegiate

A Hydrogen Atom that is traveling through Space which is an example of Movement through a Friction absent system...would never be allowed to group into a Celestial Body such as a Star as it encountered and made contact with other Hydrogen Atoms as each time these Atoms came into contact they would transfer their Kinetic Energy and never come to rest.

Gravity seems to create at the Center Point of a Created Gravity well...an Entropy of Kinetic Energy. This has been seen in what occurs in a Black Hole. Split Infinity

reply to post by SplitInfinity

A Hydrogen Atom that is traveling through Space which is an example of Movement through a Friction absent system...would never be allowed to group into a Celestial Body such as a Star as it encountered and made contact with other Hydrogen Atoms as each time these Atoms came into contact they would transfer their Kinetic Energy and never come to rest.

Gravity seems to create at the Center Point of a Created Gravity well...an Entropy of Kinetic Energy. This has been seen in what occurs in a Black Hole. Split Infinity

If the atoms have the same velocity, same speed and direction, they could be drawn together by gravity. You're right that most of the time, gas molecules collide and separate.

I don't know about the far side of a black hole, but on this side, the side our universe is in, a gravity well is not entropic. It causes predictable events.

Entropy causes unpredictable states, that is, it makes more possibilities exist. I agree that Kinetic Energy can cause entropy.

reply to post by Semicollegiate

It is the Reality that Celestial Objects exist at all rather than a Universe filled with Particles that are bouncing off one another that Gravity shows it's Special Effects. Sure we can use equations to figure out an Objects rate of fall and how much a quantity of Mass would weigh on another Planet that is either Lessor or Greater in Mass than Earth but when it comes to the actual Center of a Gravity Well...our known Physical Laws break down.
Split Infinity

Originally posted by SplitInfinity
reply to post by Semicollegiate

 

It is the Reality that Celestial Objects exist at all rather than a Universe filled with Particles that are bouncing off one another that Gravity shows it's Special Effects. Sure we can use equations to figure out an Objects rate of fall and how much a quantity of Mass would weigh on another Planet that is either Lessor or Greater in Mass than Earth but when it comes to the actual Center of a Gravity Well...our known Physical Laws break down.
Split Infinity

No... they don't....

It is quite easy to find the centroid of any three dimensional object using integrals or even deconstructive geometry. The center of gravity would be located at the centroid.
It's quite easy for a 2-dimensional triangle (vertex connected to the midpoint of the opposite side), but becomes a bit more difficult, but not at all impossible for 3 dimensional objects.

....google it if you want to know more.

reply to post by PurpleChiten

Actually...the center of Gravity would be located at the center of Mass not the Geometry of any object or even group of objects. Split Infinity

Originally posted by chr0naut

Originally posted by ImaFungi

If you were in a spaceship and the only thing existing in the universe,, everything else was pure vacuum,,, and you released a 10 kg mass, would it fall down,, all the way down,, forever?

In that instance, it would fall "down" to the only other matter in the universe, that is, you and your spaceship.

However, due to the low mass of you + spaceship, this would take a VERY long time. It would not fall as fast as things do when they fall to Earth.

ok same experiment,,, but right when you let go of the mass,,, you and your space ship disappear and are taken to another realm,,in which you view the entire empty vacuum universe,,, only with the 10kg mass ,.,,.,., which way is the mass traveling or falling?

Originally posted by SplitInfinity
reply to post by PurpleChiten

 

Actually...the center of Gravity would be located at the center of Mass not the Geometry of any object or even group of objects. Split Infinity

The center of mass is found by geometry based on the mass.

If the mass is uniformly distributed, it's much, much easier. but can still be found even if it isn't with a little bit of calculus

Like I said, google it if you want to understand

Originally posted by ImaFungi

Originally posted by chr0naut

Originally posted by ImaFungi

If you were in a spaceship and the only thing existing in the universe,, everything else was pure vacuum,,, and you released a 10 kg mass, would it fall down,, all the way down,, forever?

In that instance, it would fall "down" to the only other matter in the universe, that is, you and your spaceship.

However, due to the low mass of you + spaceship, this would take a VERY long time. It would not fall as fast as things do when they fall to Earth.

ok same experiment,,, but right when you let go of the mass,,, you and your space ship disappear and are taken to another realm,,in which you view the entire empty vacuum universe,,, only with the 10kg mass ,.,,.,., which way is the mass traveling or falling?

From the reference frame of the 10kg mass, it is stationary.

As there is nothing else in this universe, there are no other references from which we may determine movement, nor are there any sources which could be applying acceleration to the mass, so there is no way to determine that it isn't truly motionless (as it would appear from its own reference frame).

This is similar to asking "If a tree falls in a forest and no-one is there to hear it, did it make a sound?".

The answer to both these questions is, rightly: "who really gives a damn?"

Originally posted by chr0naut

Originally posted by ImaFungi

Originally posted by chr0naut

Originally posted by ImaFungi

If you were in a spaceship and the only thing existing in the universe,, everything else was pure vacuum,,, and you released a 10 kg mass, would it fall down,, all the way down,, forever?

In that instance, it would fall "down" to the only other matter in the universe, that is, you and your spaceship.

However, due to the low mass of you + spaceship, this would take a VERY long time. It would not fall as fast as things do when they fall to Earth.

ok same experiment,,, but right when you let go of the mass,,, you and your space ship disappear and are taken to another realm,,in which you view the entire empty vacuum universe,,, only with the 10kg mass ,.,,.,., which way is the mass traveling or falling?

From the reference frame of the 10kg mass, it is stationary.

As there is nothing else in this universe, there are no other references from which we may determine movement, nor are there any sources which could be applying acceleration to the mass, so there is no way to determine that it isn't truly motionless (as it would appear from its own reference frame).

This is similar to asking "If a tree falls in a forest and no-one is there to hear it, did it make a sound?".

The answer to both these questions is, rightly: "who really gives a damn?"

edit on 4/11/2012 by chr0naut because: (no reason given)

lol,,, ok,,,, well if a tree when falls produces sound waves,,,, and sound waves are sound,,,, yes it does make a sound,..,,..,.,

the reason i asked what i asked in the way i asked,,, is because i perceive it similar to the OPs question,,

if a true vacuum,,, is a particless, matterless/energyless volume....( like the one in my example of the completely empty universe) .,.,..,.

then in the OPs example,,, wouldnt the pure vacuum tunnel in the earth,,, be the same as my empty universe example?

lets say in my universe example the vacuum is in containment ( like the earth example)..... surrounding the vacuum is all sorts of stuff,,, matter energy,,, dragons,, but the pure vacuum is a pure vacuum,,, just like the one in the earth in the OPs example,,, so like the op stated,,, wouldnt there be nothing within a pure vacuum to effect a 10kg mass?

reply to post by ImaFungi


A vacuum does not cancel out gravity, it only takes other matter and the atmosphere out of the equation, producing zero drag. Gravity would be the only force acting on it, but it would still act on it.

Originally posted by PurpleChiten
reply to post by ImaFungi

 

A vacuum does not cancel out gravity, it only takes other matter and the atmosphere out of the equation, producing zero drag. Gravity would be the only force acting on it, but it would still act on it.

in a vacuum,, with no energy,, no matter,, no particles,, in a pure vacuum with nothing but nothing,,,, what gravity is effecting ,, one single object,, in the vacuum?

Originally posted by PurpleChiten
reply to post by ImaFungi

 

A vacuum does not cancel out gravity, it only takes other matter and the atmosphere out of the equation, producing zero drag. Gravity would be the only force acting on it, but it would still act on it.

lets say we construct a perfect, absolute contained vacuum in interstellar space,, and the only thing that is in the vacuum is a 10kg mass........ the mass is magnetic,,.,, and outside of the vacuum we have magnets,.,.,. would the magnets have an effect on the mass? if so,, would their effects cause our perfect, absolute vacuum to no longer be a perfect vacuum ( barring the 10kg mass in the vacuum in the first place)?

p.s. i know this is different then gravity...

Originally posted by ImaFungi

Originally posted by PurpleChiten
reply to post by ImaFungi

 

A vacuum does not cancel out gravity, it only takes other matter and the atmosphere out of the equation, producing zero drag. Gravity would be the only force acting on it, but it would still act on it.

in a vacuum,, with no energy,, no matter,, no particles,, in a pure vacuum with nothing but nothing,,,, what gravity is effecting ,, one single object,, in the vacuum?

If it's a vacuum, drilled through the center of the earth, then the earth's gravity is affecting it.

Originally posted by ImaFungi

Originally posted by PurpleChiten
reply to post by ImaFungi

 

A vacuum does not cancel out gravity, it only takes other matter and the atmosphere out of the equation, producing zero drag. Gravity would be the only force acting on it, but it would still act on it.

lets say we construct a perfect, absolute contained vacuum in interstellar space,, and the only thing that is in the vacuum is a 10kg mass........ the mass is magnetic,,.,, and outside of the vacuum we have magnets,.,.,. would the magnets have an effect on the mass? if so,, would their effects cause our perfect, absolute vacuum to no longer be a perfect vacuum ( barring the 10kg mass in the vacuum in the first place)?

p.s. i know this is different then gravity...

Again, you are not understanding what a vacuum is...

Originally posted by PurpleChiten

Originally posted by ImaFungi

Originally posted by PurpleChiten
reply to post by ImaFungi

 

A vacuum does not cancel out gravity, it only takes other matter and the atmosphere out of the equation, producing zero drag. Gravity would be the only force acting on it, but it would still act on it.

in a vacuum,, with no energy,, no matter,, no particles,, in a pure vacuum with nothing but nothing,,,, what gravity is effecting ,, one single object,, in the vacuum?

If it's a vacuum, drilled through the center of the earth, then the earth's gravity is affecting it.

the earths gravity is effecting it,,, because the vacuum would be in the earths space - time distorting gravity well?