# Why is it a problem that gravity is so much weaker than the other forces?

1. Aug 17, 2010

### camel_jockey

I will write the following as if I know what I am talking about, feel free to correct me :)

Okay, so we have theorized (using general relativity) that the force of gravity is in fact a fictitious force, resulting from observing motion in a curved spacetime. It is therefore unlike the other forces, which are considered to be real in the sense that they are not illusions resulting from poor observation.

Also, gravity is purely an attractive force, and therefore also fundamentally different to the other 3 forces.

Why then do we think it uncomfortable that gravity is "10^-38 times weaker" than the strong force, or whatever the factor is (we all know it to be small)??

Is it not totally OK, since gravity isn't a force and we shouldn't be making this comparison?

Or does this stem from the desire to have gravity, whatever it may be, being mediated by some force-carrying particle such as the graviton??

I don't understand really why it is considered a problem, but I have heard people talking about it. Would be nice if someone could explain the crux of the matter to me.

2. Aug 17, 2010

### HallsofIvy

?? I don't have any problem with it and I surely am not "uncomfortable" with the force of gravity being so small. In fact, I fell sure I would be extremely uncomfortable if it were 10^38 times stronger!

Please give some specific examples in which it is considered a "problem".

3. Aug 17, 2010

### camel_jockey

In the sense that many theorists and QFTists have said that it is a problem - I don't know if it really is! That's the question!

4. Aug 17, 2010

### Izhaki

In literature I came across, gravity being weak as a problem is often mentioned with relation to how hard it is to 'measure' or 'detect' gravity in experiments.

For one, the idea that a pill-size magnet overpower the gravity of a very big planet in preventing your keys from falling towards earth, goes to show what scale of bodies you need in order to experiment with gravity. Then, as other forces are much stronger, they might interfere with trying to 'measure' gravity.

My two pence.

5. Aug 17, 2010

### Dmitry67

The problem is that you can build a dimension-less constant in order of 10^38. For example, in H atom, proton and electron attract gravitationally 10^38 times weakes than electomagnetically.

The problem is that is ruins any hope to deduce that huge number from the first principles. It cant be PI, or PI^PI, or even exp(exp(PI)) or something. While all other parameters of the Standard Model are in the same range (expect neutrino masses, but there is an explanation), and even some parameters can be calculated (Koide formula - http://en.wikipedia.org/wiki/Koide_formula ) there is no hope that gravity will be ever explained that way.