# Fourth Fundamental Force 1986

1. Dec 9, 2005

### shanu_bhaiya

We know that there are three fundamental forces:

1. Gravitational Force
2. Strong Nuclear Force
3. Quark-Quark Force (unified by Weak Nuclear and Electromagnetic Force)

I've heard about the fourth fundamental force which was found in 1986 and changed the relation:
F = G*m*M/R*R
to some another relation.

2. Dec 9, 2005

### Staff: Mentor

Nobody was able to confirm the "fourth force" results, as I recall, and I think they were finally explained as a faulty analysis or experimental error.

3. Dec 9, 2005

### Norman

I believe you are slightly confused. The interactions of the color field (quarks and gluons carry color- no other fundamental particle do). The weak force involves leptons and changes in the "flavor" of particles and the electromagnetc involves charged particles.
Gravitation of course deals with mass. Quarks carry both color charge and electric charge so they participate in all of these fundamental processes. Leptons (for instance electrons, muons, etc) do not carry color charge and there for do not interact through the strong nuclear force.

As far as the idea that Newton's Universal Law of Gravitation is incorrect, I would take it up with someone who knows a little more about General Relativity. GR is Eintsein's law for gravity which radically departed from our previous notions of gravity. This did not happen in 1986 though.

I hope I cleared up some information.
Cheers,
Ryan

4. Dec 9, 2005

### Staff: Mentor

At that time someone reported very precise measurements of gravitational force as a function of distance, that appeared to deviate from 1/r^2 proportionality. They suggested that the deviations might actually be a separate fundamental force. There was a lot of discussion about this "fifth force" for a while. More careful experiments didn't confirm this, and I think someone found possible sources of systematic error in the original experiment. This was almost twenty years ago, so my memory is vague.

5. Dec 9, 2005

### ComputerGeek

haven't they been able to combine the strong, weak and electromagnetic forces into one force?

6. Dec 9, 2005

### Norman

Nope. Lots of work being done in this area though. The standard model uses strong and electroweak but they are not unified in the theory.
Cheers,
Ryan

7. Dec 11, 2005

### shanu_bhaiya

They are trying and many of the Great Unifying Theories are being made in order to unify all the forces. TOE is 1 of the greatest...

8. Dec 11, 2005

### Norman

I think you are confused. Grand Unified Theories or GUTs look to unify the strong force with the electroweak in the same way that electromagnetics and weak interactions were unified. Theory of Everything or TOE looks to unify all the fundamental forces (gravity, electroweak and strong). I believe that M-theory would be classified under an attempt at a TOE. But I am by no means an expert in Strings and their theories.

But their is a distinct difference in GUTs and TOEs- that being the inclusion or exclusion of gravity.

Cheers,
Ryan

Edit: I just realized I misread the post I am quoting: I have never heard of Great Unified Theory. I assumed this person simply meant Grand Unified Theory. But I may be wrong and if I am the post is still here to clear up any other misconceptions.

Last edited: Dec 11, 2005
9. Jan 2, 2006

### ohwilleke

It is customary to speak of four forces (Gravity, EM, Weak, Strong) despite electro-weak unification. Thus, an additional force would be a fifth force.

There are a couple leading candidates out there for fifth forces. The strongest one is as a mechanism to explain what is commonly called "dark energy", i.e. a tendency of the expansion of the universe to accellerate. Another one is the notion that perhaps the phenomena known as "dark matter" is instead a fifth force. However, even among people who explore dark energy and dark matter phenomena as problems in the existing laws of nature rather than from a "missing stuff" hypothesis, the usual approach is to modify existing general relativity equations, rather than to create a truly independent fifth force.

Another approach to getting to a fifth force would be to describe the inertia effects of a Higgs field as a force.

10. Jan 13, 2006

### Scottbob

There is the Casimir effect. That could be a 5th force. It happens when two plates very close together disturb the vacuum energy and move together... or something.