Interfering Gravity

[mortonman1]

Hi,

I have never taken physics, i am in high school, but i had a little theory i was hoping you guys could comment on.

I was thinking that the earth's gravity would be a lot greater if the moon and sun didn't exist. This is because the moon's gravity, is taking away from the Earths, and the earths from the moons. i know occording to what they teach you this isnt true, but i just want you to think about ity for a second and get back to me. i really appreciate it. And i tried calculations and found that there is a loss of .13m/s squared between the earth and moon due to interfering gravity. unfortunately, im almost positive my math is slightly off. try it yourself and see what you get personally. i wont tell you my process yet so that it doesnt interfere with your style of thought.

 

This little theory led me to think that the orgin of the universe could have been from to small particles that gained infinite potential gravitational energy because they were the only two particles in the universe, and they thus collided, creating the big bang. according to newtons universal gravitational constant, this is merely impossible, but he didn't take into account any theoretical universes with no other matter or masses around.

 

let me know! thanks

[Spyman]

If you connect two different springs on one object and then pull apart the strings in different directions you will end up with the object inbetween them in equilibrium and the net sum of forces acting on the object is zero. But that doesn't mean that the strenght of the springs are lesser at the object, they are still acting on the object.

 

The influence of Earths gravity on a spaceship going towards the Moon is negated by the gravity from the Moon and if the spaceship passes the Moon then their gravity are effecting the spaceship added together. But the individual forces of gravity from each body acting on the ship is not changed even if the sum of their forces are.

[swansont]

Interference has a specific definition in science, and is not present here. Forces are vectors and can combine. The net force on you varies slightly with the position of the sun and moon. I recall reading about an experiment with some pendulum clocks (whose period depends on the net acceleration from gravity) that showed the lunar variation. However, there a lot of complications to this, because the earth is not a rigid sphere, and that has certain implications in the concept — the mass distribution near you and the distance to the center of the earth change, which affects g.

[mortonman1]

well i understand what both of you mean i think. I have no idea what Lunar variation is however... so if your willing to explain thatd be great. So in response to Spyman, that space ship in between the moon and the sun wouldn't be at equilibrium with gravity right? if the ship were let go, considering it werent in orbit, it would go to the earth right?

[PaulS1950]

There is a point between the Earth and Moon where the pull from each object is the same from both directions the ship without momentum would stay in that spot (as long as it was directly between the Earth and moon which would require it to be traveling with the Moon around the Earth) It would not be a true Earth orbit as such.

 

Is that right?

[swansont]

well i understand what both of you mean i think. I have no idea what Lunar variation is however... so if your willing to explain thatd be great.

 

The position of the moon does not vary on a sidereal or solar day, because of the motion of the moon. The gravity it exerts varies with position, i.e. reduced when the moon is overhead, increased when it's on the opposite side of the planet, and you can pick this signal out because it's at a distinct frequency.

 

I wrote up a 3-part summary of the papers. The results are presented here:

http://blogs.scienceforums.net/swansont/archives/448

[Spyman]

well i understand what both of you mean i think. I have no idea what Lunar variation is however... so if your willing to explain thatd be great. So in response to Spyman, that space ship in between the moon and the sun wouldn't be at equilibrium with gravity right? if the ship were let go, considering it werent in orbit, it would go to the earth right?

Lunar variation is how the pull of gravity from the Moon changes when the Moon orbits the Earth and therefor affects us down here differently depending on where it is in its orbit. If the Moon is above you its gravity will pull slightly up on you and counter Earths gravity a tiny bit, but if the Moon is on the other side of Earth than you are then its gravity will pull slightly down on you adding to Earths gravity a tiny bit. One example of this is the tides of sea level caused by a combination of the gravity from the Sun when Earth spins and the gravity from the Moon when it orbits.

 

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An astrounaut standing on the Moons surface looking down at Earth will not fall down to Earth and someone walking here on Earth under the Moon will not fall up to the Moon either.

 

At the surface of the Moon the gravity from Earth is small due to the far distance and the gravity from the Moon is strong since the astronaut is close to it, and it's likewise but opposite for us standing here down on Earth and looking up at the Moon. But gravity gets weaker with distance so there must be a point somewhere inbetween Earth and the Moon where their gravity will negate each other exactly and at that point both the gravity from the Earth and the Moon is equal strong but pulling in opposite directions. This point is one of the Lagrangian points.

 

If the spaceship is parked at the Lagrangian point between the Earth and the Moon then it could float there without being in orbit or burning fuel in its engines to counter gravity. But if the Spaceship gets closer to Earth it will fall to Earth and if it gets closer to Moon it will fall down on the Moon. And since the Earth is bigger and has more mass its gravity is stronger than the Moons so the point where their gravity is equal is closer to the Moon.

 

 

There is a point between the Earth and Moon where the pull from each object is the same from both directions the ship without momentum would stay in that spot (as long as it was directly between the Earth and moon which would require it to be traveling with the Moon around the Earth) It would not be a true Earth orbit as such.

 

Is that right?

Yes, that is one of five Lagrangian points.

Edited May 21, 2010 by Spyman
Fixing Link

[mortonman1]

perfect answer thank you. Now answer my question about the orgin of the universe. "This little theory led me to think that the orgin of the universe could have been from to small particles that gained infinite potential gravitational energy because they were the only two particles in the universe, and they thus collided, creating the big bang. according to newtons universal gravitational constant, this is merely impossible, but he didn't take into account any theoretical universes with no other matter or masses around."

[Spyman]

The scientific view and observations clearly disagrees with your idea of greater gravitational energy with lesser mass. Also Newton was very able to reason and speculate of different theoretical universes.

 

I suggest that you read more about the Big Bang and Newton's gravity:

 

"The Big Bang is the cosmological model of the initial conditions and subsequent development of the Universe that is supported by the most comprehensive and accurate explanations from current scientific evidence and observation."

http://en.wikipedia.org/wiki/Big_Bang

 

"Newton's law of universal gravitation states that every massive particle in the universe attracts every other massive particle with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them."

http://en.wikipedia.org/wiki/Newton%27s_law_of_universal_gravitation

[mortonman1]

ok thanks. ill do my research.