Origin or source of gravity?

wolram

I guess most people know what it does but, AFAIK no one as yet knows the origin (other than the BB) of how gravity came to be or what it (is), why is the origin of gravity so elusive?

Sundance

Hello Wolram

To begin with the BB is only a theory and not a fact.

All info points to an infinite universe with endless time, space and matter. If this is correct than Gravity has no Origin and therfore would seem instant.

castlegates

Beacause it's right under our noses.

Parlyne

I'll have you know that my mustache is not, in fact, the origin of gravity.

DaveC426913

What is your mustache doing right under my nose?

Bart

What info?

russ_watters

Why should gravity be any different than anything else? We know no more or less about it than we do the other three forces.

marcus

the most accurate theory of gravity, currently, represents it as the way matter affects geometry. I think this remains mysterious. How can matter affect geometry?

and there is the puzzle about inertia. why should stuff follow geodesics? and why should a thing's inertia ("inertial mass") be the same as the ("gravitational mass") strength with which it bends geometry? this does seem elusive, to use your word.

I've just been reading a 2001 book by Smolin called *Three Roads to Quantum Gravity* and I'm amazed at how good it is. Didn't expect such clarity and depth in a popular-written book. The last chapter has a prospective on how these very same problems might eventually (over next 10 years say) be addressed and solved. nice thing is that he doesnt just trivialize the problems---he takes a serious look into them. Great book.

DaveC426913

I would say we know less about gravity than the other forces. For one, we know how the other forces are related.

marcus

For sure! And there's an accurate picture of them within a static geometric framework (Euclidean or Lorentzian). You don't need General Relativity to describe electromagnetism.

dilletante

I guess I don't even understand if there is a consensus on whether gravity is a force or not. While apparently GR does not consider it a force, what about QG or string theory? If they postulate a graviton as a carrier, do they consider gravity a force, in opposition to GR?

TR345

It may be that there are certain preconceived notions that have made there way into mainstream physics which hinder our ability to look for gravity. Our "best" "most accurate models are fundimentally flawed. We need to start back at the basics and let go of some of mainstream physics assumptions. The problem is that mainstream physics is about results and not understanding, effect and not cause. We have built pyramids on effect and left cause behind in order to make critical advancements in technology to win wars and stay competative with other countries. Our egos have exceded our understanding and we are too proud to go back and re-trace our steps.

Chronos

I think it is fair to consider gravity as a force. Newton gave this considerable thought.

pervect

The main problem with regarding gravity as "just a force", is that it cannot possibly explain gravitational time dilation.

Bjarne

Could it be that force that 'pulls' space until it bend / curves
So that both Einstein and Newton both was right?
If so we have also achieved a deformation of space / time – right?
What I mean, - it seems like matter effect space somehow, - for instance black holes of galaxies, but also even the elementary particles 'interacts' with space
Fx.
1.) http://en.wikipedia.org/wiki/Frame_dragging
2.) http://en.wikipedia.org/wiki/Black_hole_electron

Chronos

This line of reasoning is entirely consistent with GR.

jonmtkisco

Hi Bjarne,

I think it's fair to say that most, but certainly not all, physicists agree that gravity curves the geometry of space. Some say that "gravity acts on space" while others more conservatively say that "gravity acts on matter."

Since the effects of gravity perfectly mimic a curvature of space, as far as I know there's no (known) way to be sure whether space is actually being curved, or instead whether instead the "force" of gravity just adheres to a geometrically-based algorithm. It's really a fascinating but (so far) quasi-philosophical question.

There appears at this time to be no justifiable reason to doubt the predictions of GR, but it is very sane to question whether the geometry of space is actually capable of curvature. It's similar to asking whether there really can be more than three spatial dimensions. By definition it's impossible to know, but mathematical formulas are unbounded by physical reality, so we can imagine a higher-dimension spaciality in excrutiating detail. Are advanced theorists modeling reality or just building beautiful sandcastles in the air? Who knows?

I think that in GR there is no functional distinction between a "force" and "pseudo-force". Einstein appears to personally have favored the notion that gravity is a "real" force, and therefore that, for example, the coriolis effect is also a "real force". But most GR specialists after Einstein seem to believe that both are mere "pseudo-forces."

In another semantic sense, the definition of "reality" is what's undefinable here. Einstein said that reality is only a category that we choose to put some things into and not others. But we must categorize on a principled basis.

Jon