How does gravity actualy work?

[Hav0k99]

Has the method of it's existence ever been proven or is it all theory?

 

[Born2bwire]

Magic.

 

[PowerEngineer]

Read "The Fabric of the Cosmos" by Brian Greene

 

[artikk]

gravitons

 

[DrPizza]

It's the least understood of the 4 forces.

 

[VinDSL]

Originally posted by: DrPizza
It's the least understood of the 4 forces.

That's because 'they' think it 'pulls' objects. Gravity actually 'pushes' them...

 

[Mday]

Originally posted by: Hav0k99
Has the method of it's existence ever been proven or is it all theory?

mostly been theory. Until we can manipulate it, we cant confirm anything. We just know stuff "falls down"

 

[RossGr]

Modern Physics simply does not address that question of how. We can only observe and make mathematical models to simulate the observed behavior. How, unless you are happy with a mathematical answer, is not a physcal question.

 

[MrDudeMan]

Originally posted by: RossGr
Modern Physics simply does not address that question of how. We can only observe and make mathematical models to simulate the observed behavior. How, unless you are happy with a mathematical answer, is not a physcal question.

exactly. this is also a classic point of contention between the ignorant when discussing science versus religion. they answer different questions, how and why. i know that is off topic but it annoys me when people confuse the two or when they say "i believe in physics."

 

[sao123]

Originally posted by: PowerEngineer

Read "The Fabric of the Cosmos" by Brian Greene

yes yes...very good book. and read his other book too.
the black one.

 

[TITAN126]

We have yet to figure out why gravity works. However, one thing that I found very interesting while studying physics this year was the similarities between Newtons's Law of Universal Gravitation (F = G*((m1*m2)/r^2)) and Coulomb's Law (F = kc*((q1*q2)/r^2)). Notice that the only thing that differs betwen these two formulas is the constants G and kc. I just thought it was interesting that these two very different fields of physics could have such similar formulas. Maybe they could be connected somehow? I doubt it, but I still think it's cool.

 

[herm0016]

That is an intersting comparson. and that is one of the things that moden physics is trying to answer. the forces of gravity and the forces of electromagnatisim are seperate theroys with that similarity. quanum physics, and a number of different theroys like string, chaos, multi-diminsion, and others are being worked on to explain the connection, but the connection point lies at such a deep level that we are unable to measure things without changing them, we dont have probs, or things to measure things that are that small.

 

[DrPizza]

You know... now that I think about it, I also have a question about gravity...

Einstein's bending of space vs. gravitons... If space is bent, are gravitons necessary?

 

[herm0016]

both just theroys. gravatons transmit the force, like electrons transmit electricial forces and create a magnetic feild while doing it. gravatons transmit gravity and produce a gravatational feild while doing it. at least that seems to me how it would work.

 

[gsellis]

Have to get this out of the way...

There is no such thing as gravity. The earth sucks.


As noted. If someone could actually explain it, the next question would be where were they going to spend the money they got from the Nobel prize group. Last time I heard, we still don't even know the speed of propagation. Some sci-fi writers have assumed it was faster than c as it makes good story. David Weber used it for communications and Alan Dean Foster used it for a drive (K-K).

 

[JohnCU]

why has no one mentioned the general theory of relativity?

 

[silverpig]

Originally posted by: TITAN126
We have yet to figure out why gravity works. However, one thing that I found very interesting while studying physics this year was the similarities between Newtons's Law of Universal Gravitation (F = G*((m1*m2)/r^2)) and Coulomb's Law (F = kc*((q1*q2)/r^2)). Notice that the only thing that differs betwen these two formulas is the constants G and kc. I just thought it was interesting that these two very different fields of physics could have such similar formulas. Maybe they could be connected somehow? I doubt it, but I still think it's cool.

The factors of G and k (or 1/4*pi*Epsilon if you like) are just unitary conversion factors. They get you feet or meters or whatever units you like. The 1/r^2 dependence comes from the fact that we live in 3 dimensions. If we had 4 spatial dimensions, it'd be 1/r^3...

The mass/charge bit just allows for different strengths.

Besides, neither of these formulas is entirely accurate, so it's kind of moot. As of now GR describes gravity, and QED describes electromagnetism, and those theories are entirely different to the point where they definitely do not work together at all.

 

[ClayN]

"his other book too. the black one."

The Elegant Universe

"...those theories are entirely different to the point where they definitely do not work together at all."

Sure they do. We just don't know how.

 

[bobsmith1492]

I've heard recently about some major setbacks to string theory, though I haven't looked into them... really, they're likely grasping at straws, or in this case, strings. Of course, Greene noted in his book other times in the past where string theory went down the tubes until some new math came along, but still, it seems tough to make those sorts of theories without more data.

Anyway, does anyone know exactly how electrostatic attraction really works, even? I've heard explanations about the strong force, I think it was, in that protons and neutrons actually exchange certain sub-subatomic particles (quarks?), but not about the "like repels like" (and vice-versa) electric force.

 

[DrPizza]

bobsmith, there's a summary at Wiki on the force carrier particles. here You can branch off from that page to read more.

 

[PowerEngineer]

Originally posted by: DrPizza
You know... now that I think about it, I also have a question about gravity...

Einstein's bending of space vs. gravitons... If space is bent, are gravitons necessary?

It's my understanding that both descriptions of gravity are expected (because no one has actually "seen" a graviton) to be valid and yield the same results. It's postulated that all forces between objects can be thought of as either the fields of the objects interacting or as exchanges of "messager" particles between the objects. For electromagnetic force, the field are electromagnetic and the "messager" particle is the photon.

Here's a link for starters...

:thumbsup:

EDIT: looks like you already found the answer...

 

[savvy]

Originally posted by: TITAN126
We have yet to figure out why gravity works. However, one thing that I found very interesting while studying physics this year was the similarities between Newtons's Law of Universal Gravitation (F = G*((m1*m2)/r^2)) and Coulomb's Law (F = kc*((q1*q2)/r^2)). Notice that the only thing that differs betwen these two formulas is the constants G and kc. I just thought it was interesting that these two very different fields of physics could have such similar formulas. Maybe they could be connected somehow? I doubt it, but I still think it's cool.

Interesting.

 

[bobsmith1492]

Photons, eh? Huh, I did not know that.

 

[silverpig]

Originally posted by: ClayN
"his other book too. the black one."

The Elegant Universe

"...those theories are entirely different to the point where they definitely do not work together at all."

Sure they do. We just don't know how.

No they don't. If you try to quantize GR you get scattering probabilities involving infinities. The theories right now are entirely incompatible. Gravity itself and quantum mechanics itself probably work together sure, but the theories we have describing them do not.

 

[silverpig]

Originally posted by: DrPizza
You know... now that I think about it, I also have a question about gravity...

Einstein's bending of space vs. gravitons... If space is bent, are gravitons necessary?

If you think of there being an EM field everywhere which photons can pass through as little ripples, then you can think of space being like a gravity field which gravitons can pass through as little ripples.