That GUT feeling

For centuries, well, decades, at least, mankind had striven to find a theory of "everything". That is, one single math formula that describes all of physics.

That goal is still some way off, despite massive strides that have been made towards it.

The argument goes something like this:

A total of four different forces have been identified. Please note as opposed to the previous post, these are specific kinds of force, whereas the previous post dealt with the CONCEPT of a force.

These four "types" of force hold the Universe together. However, they are somewhat limited in various ways.

In detail, these are they:


The Oldest known, Gravity. It acts on everything and is always attractive.

The next to be studied was Electricity, or as it is now known, Electromagnetism. This acts only on stuff that is electrically charged. That is, stuff that is not neutral electrostatically. We do not know what charge "is" yet, even today, just that stuff with the same "charge" repel, and stuff with opposite "charge", attract. There are only two of them

The third force is called the "strong" force, is always attractive and acts only on stuff that is desperately close.

The fourth is the "weak" force (we ran out of names long ago) and only acts on radioactive stuff (it causes atomic nuclei to split up)

There are no others

Each of these "forces" has it's own set of equations that describe only it (electromagnetism has four of its own)

It has long been a dream of all science to unite all these equations into one.

It has not been done yet.

They all seem to have two things in common, though. They all have a specific "range" and all use "exchange particles" to be felt. That is except gravity. Gravity has infinite range, but no "exchange particle" has ever been detected.

There may be hope, though. In 1974, Steven Weinberg and Abdus Salaam (I forget the name of the third), managed to marry the "weak" force with electromagnetism, calling it the "electroweak" force. The prediction, if this were true, would be three new "exchange" particles called the W+, W- and the Z-0. It wasn't until 1983 that we had the particle accelerator powerful enough to produce them, as they were predicted to be very heavy (E = mc squared, after all). Sure enough, they turned up.

So we had three forces now, not four.

There have been reliable equations suggesting that the "electroweak" can be married to the "strong" force, although to prove this we would need an accelerator the size of the galaxy to detect these exchange particles (dubbed the "X" particles)

However, there was another prediction from this marriage - proton decay. Protons are to all intents and purposes, stable, although the other one, the neutron, decays in about 16 minutes.

If the Electroweak and the Strong forces, were really part of a bigger picture, the proton would have a half-life of about 100000000000000000000000000000000 years (1 followed by 32 zeroes).

Since the universe is only about 15000000000 years old, none would have gotten round to decaying yet, UNLESS we watched 100000000000000000000000000000000 protons for a year.
Us peeps have been doing this for maybe a decade now, and so far no results (it is very hard to detect just one amongst all those, even without red herrings coming from just about everything else.)

If we do detect proton decay, we will only have gravity to deal with.

That is the be-all and end-all. Gravity, almost like an unusually stubborn mule, blatantly refuses to conform.

Ok, so there may be a way out by conjecturing "m-theory", "brane-theory", and "string-theory", but to prove this requires travel in eleven dimensions. In other words, these are only words, not proof.

Warning! SUBJECTIVE STUFF!

Gravity differs because it is geometric as refined by Einstein. The other three are gauge FIELDS, and require exchange particles to be felt.

Geometry by definition does not require exchange particles and I am surprised that even Einstein tried to meld his own theory with the other established forces. Maybe it was peer pressure.

END OF SUBJECTIVE STUFF

Suffice it to say, we do not really have a Grand Unified Theory (GUT) yet, although we may have one for everything except Gravity.

The whole picture can be summed up in an energy diagram (see below), as we believe all the forces were one once, when there was so much energy there was no distinction. As the Universe expanded from the Big Bang, the amount of energy decreased (per cubic meter) and the forces separated in a process known as "symmetry breaking". Th.e diagram shows that gravity is conjectured to be there, but that is more like hope than speculation

We try to address this by putting lots of energy into our particle accelerators to maybe recreate conditions as they were during the big bang.



We still have a GUT feeling one is out there somewhere. Lord knows, we've tried!