The All-Singing, All-Dancing.......

The Ultimate Quest of Physics, rather like the Answer to the Ultimate Question of Life, the Universe and Everything, or the Search for the Holy Grail, is a bit like a gut feeling.

You know it is there, but you cannot QUITE grasp it (yet).

Some call it the "Theory of Everything" and basically, it will be (or wioll haven be) a set of equations that will tell us how the whole shebang (as in big shebang) works.

Others call it a "Grand Unified Theory".

Whatever it wioll haven be called, it will marry the four forces known in nature. People already know the first two, gravity and electromagnetism, but the other two do not come into contact with the general public.

This is because they are only useful when scientists like to look at the science of the very small. They are called the "strong" and the "weak" "nuclear forces. The names are only historic names, but suffice it to say, there ARE four forces at work (as opposed to the three military ones).

Science had a triumph in 1974 when Abdus Salaam and Steven Weinberg came up with the "electroweak" set of equations, which were a combination of the electromagnetic ones, and the equations for the "weak" nuclear force.

Science is a very solid foundation of investigation, and if a new theory is put forward, it has to make new predictions about what will happen when we apply it. The "electroweak" theory predicted three very heavy particles, the W+, the W-, and the Z0, the so-called "intermediate vector boson". At the time, atom smashers were not powerful enough to even look for these, so the physics community decided to build bigger ones to try.

In 1983, after the completion of one of these, we found the Z0. The theory was venerated, and we knew we were on the path to true understanding.

So we now had three theories, gravity, strong force, and electroweak. In including the strong force, theorists easily predicted that if we are to unite the electroweak with it, the proton would have to decay of its own volition in free space.

We have known for a long time that on average, a neutron decays into a proton, an electron and an antineutrino (in about 16 minutes) for decades, but this new prediction was almost more than we could bear.

When we plugged the numbers in, we found that on average, the free proton was expected to decay in about 100 000 000 000 000 000 000 000 000 000 000 years. (1 followed by 32 zeroes). This is a bit hard to measure. To get around this, we had the bright idea of watching that many protons for a year.

No-one has seen anything yet, owing to us having to screen out every other event that could be misconstrued as a proton decay.

Now, it you think THAT is difficult, try merging gravity into all of this. There have been theories, none really creditable, to unite gravity in the same manner. Two are called "supersymmetry" and "supergravity". They predict new particles, of course, but none have ever been detected because gravity is by far the weakest of all the forces.

Einstein tried in vain until his death in 1955, to unite gravity. The "cosmological constant" mistake that he himself admitted to, pales into insignificance when compared with this.

With Einstein's own equations, he proved that gravity was a geometric effect, not a gauge force. With this in mind, as far as I know, and this alone in this post is my opinion, you cannot "marry" gauge forces with geometry. It is akin to saying "let's unite the equations of the wind with the equations of how plastic is made". In other words, the two are totally incompatible.

THIS, not the cosmological constant, was Einstein's Greatest Mistake.

As for the Unified Field Theory, or the Grand Unified Theory as it is now known, we are still studying huge tanks of carbon tetrachloride for that elusive proton decay, in the hope that it will "clean" the strong force.

Some people claim that a new theory, called "String Theory" is the answer to all these questions. It is a fact that this mathematics has strong indications that it may well be the key, but not even the math guys understand the full implications of the math they themselves have discovered. To sum up, the theory involves math in 10, 11 and 26 dimensions, which is all very well, except for one thing - how does one 'prove' the theory right, when one cannot even get to the fifth dimension?

Obviously, a lot of guts are involved in that kind of travel!