why are they looking for a gravitron particle when gravity is a force from curved space?

Question

so what your saying is this particle is capable of reaching atoms and pulling on them from the middle of the galaxy and beyond

Answer 1

They're looking for a explanation of gravity on a very small level. Particularly because of black holes where Einstiens theories go haywire.

Answer 2

Because curved space is only a theory. In all other forces (electromagnetism, weak nuclear, and strong nuclear), there is an elementary particle that causes that force (photons, gluons, and W and Z busons respectively). Therefore, we figure that since they have an elementary particle, it would only be logical for the gravitational force to also have an elementary particle.

Once one of the theories has been proven beyond a reasonable doubt, we would stop searching for the graviton. And no, as of currently, quantum physics and Einstein's relativity are NOT compatible. That is why scientists like Stephen Hawking have been trying to find what is called the Grand Unified Theory, or GUT theory, which encompasses both.

Answer 3

Because there is an underlying belief that all the forces must stem from a single force. Since quantum theory can describe teh other three forces (electromagnetism, weka force and strong force), if gravity is to be unified into the picture it must a quantum mechanical theory assoicated with it. In quantum mechanics, forces are exerted by the exchange of particles - electromagnetic force is the exchange of photons between charged particles, in the strong force pions are exhcnaged between hadrons, etc. So there has to be a particle that is exchanged between masses for gravity hence the need for a spin 2 boson called the graviton.

Now efforts to formulate a quantum theory of gravity have been unsuccessful to date. It is a very difficult theory and the methods one normally uses to qunatize a theory fail in gravity. String theory proports to get around these problems but has a laudry list of its own problems so the search continues.

Answer 4

There are two amazingly important theories in physics: General Relativity and the Standard Model of particle physics. Each has been tested more than any other theory devised by man, in more and more obscure or exacting ways, with higher and higher accuracies - and both have have passed with flying colours and have been shown to be profoundly right.

So the 'theory' part of their name does not imply that they are untested, uncertain, or just someone's harebrained idea. It is just that science often gives deadpan names for the most important things. Here "theory" means "system of operation", or something like that.

Anyway, my point is that these two theories are remarkably reliable in describing the real world. The problem is that they are incompatible and don't work together. You've probably read all about that. You use one theory for one set of predictions or observations, and the other theory for another.

Now, Gravity is the area of physics that lies in the 'overlap' between the two theories. General Relativity is a theory of gravity, and the Standard Model is a theory of particle physics looking to expand to include gravity.

Physicists and mathematicians have been trying for 50 years to find how these two theories can be combined - so far without definite success. They are being extremely creative in trying to find models that can explain both systems, and Gravitons are particles they have proposed in some of these models. They are trying to reconcile a particle approach (Gravitons 'mediating', to use their language, the gravitational force) with the curved space-time model of relativity.

Imagine General Relativity is a circle, and the Standard Model is a rectangle. Theorists are trying to find the right shape (model) that has the properties of a cylinder - that looks like a circle from one perspective, and a rectangle from another. In this simple analogy you can see how a cylinder is a much more complex shape than either the circle or rectangle it aims to synthesize - and this is the problem theorists are facing.

Just like wave/particle duality in physics, both approaches (particles/curvature) to gravity may turn out to be right - leaving our poor humans brains to boggle at trying to interpret how something can be two dissimilar things (to us) at the same time.

And it might be that Gravitons are NEVER discovered - that would tell us a lot, and we could rule out whole classes of model for this combined theory.

Answer 5

Great question. I've always wondered that myself. Are they trying to disprove Einstein's theory of curved space-time? Or are the two compatible? Hope someone answers.