The main question is: Why Gravity takes effect on Matter?

[derekwillstar]

Here is a classic thought experiment about gravity.

Imagine you could have a tunnel that goes straight down to the center of the Earth.  It's like a giant elevator shaft.  Imagine you could ride in an elevator all the way down to the center of the Earth, which is about 6371 kilometers away from the surface of the Earth.

So the question is, what happens to the gravity as you go down?  What is the gravity at the center of the Earth?

No cheating.

I am able to cheat as you are, since none of us will ever find in the center of the planet 


we can address the question only in theory, and you ask 2 questions ....


I propose 2 answers:


1) if we consider the old law of gravity,    once the center of the earth, you would be surrounded by the mass of the planet that would attract your mass on all sides, this would mean an absence of gravity (in the precise center of the planet) !


2) if we consider the theory I am presenting (law of rhythm by Pier Luigi Ighina : http://www.fortunadrago.it/?page_id=279), and consider the planet hollow on the inside, the monopolies that come from the sun, having gone through the entire planet, will be coming from all sides, colliding in a single precise point, inverting and giving origin to a small sun (aurora) internal to the planet.
Since the flow of gravity close to its origin, the result inverted with respect to the surface of the planet, making the theoretical hollow earth habitable. 


What is the gravity at the center of the Earth? ... we should be there to be able to say! 

[MileHigh]

You are correct that there would be no gravity at the center of the Earth.  The formula that most of us must have learned in high school is F = G M1 M2/r^2.   G = 6.67 x 10^-11 (you can look up the units for G)

The Earth is not hollow and this is known for many reasons.  The one that I first think of is the fact that they can do an "ultrasound" on the Earth by tracking earthquake wave reflections from the center of the Earth.  If the Earth was really hollow they would see a different pattern of earthquake wave reflections.

[tinu]

The Earth is not hollow ....

http://www.youtube.com/watch?v=4zKLL167KOE

?

[JouleSeeker]

Thanks -- this vid is also interesting, an alka-seltzer tablet added to a water droplet in microgravity.  Note his comment about larger air bubbles forming at times in the droplet, sometimes at the poles, once evidently in the center.

http://www.youtube.com/watch?v=bgC-ocnTTto

I suppose that the earth itself was once molten, a large liquid "droplet" in space, in "microgravity" conditions. 
(This does not PROVE anything regarding the earth, but shows what may be possible in such conditions.)

[derekwillstar]

You are correct that there would be no gravity at the center of the Earth.  The formula that most of us must have learned in high school is F = G M1 M2/r^2.   G = 6.67 x 10^-11 (you can look up the units for G)

Without going o.t. (question is: Why Gravity takes effect on Matter?)


I wanted to emphasize is that the gravity, among other things is also very accurate (a grave falls perpendicularly to itself)


http://upload.wikimedia.org/wikipedia/commons/thumb/7/7d/Gravity_gravita_grave.gif/120px-Gravity_gravita_grave.gif


This is possible because the gravity is "resultant force"!


Between the mono-magnetic streams descending from the sun and ascending from the center of the earth to the sun (becoming once you reach the sun, sunspots)


to help the understanding of how to coexist swirling flows opposite to each other, please consider the following animation of the vortex tube:

http://www.fortunadrago.it/wp-content/uploads/2011/09/vtanim2.gif


it is only an example of how they can work!


In the case of gravity, the flow (red) from our sun is descending at a speed greater than the ascending (blue) in the sun and from the reflection in the center of the earth.
Gravity is then stabilized and gives Graves (matter that is crossed by them without obstacles) the known acceleration of g, equal to 9.80665 m / s ²