eli5- what is Einstein’s unified field theory?


eli5- what is Einstein’s unified field theory?

In: 0

An idea that all fundamental forces can actually be expressed as different aspects of the same force, a single formula system, a “theory of everything”.

So far it wasn’t solved, we could unify 3 of the 4 forces, but the last one (gravity) is being very difficult and defies all attempts. A bunch of modern theorethical physics is working towards that goal, all the string theories, supergravity and M-theory try to solve that.

Whats stopping us is basically quantum physics, we found that to truly understand electromagnetism and the strong and weak nuclear force we have to view them through the lense of quantum theory wich says that everything can only change as discrete energy packages, and that each particle has wave properties. The math to do that simply fails when you try to apply it to gravity, we found no way to quantify it yet, so we have no clue what happens if quantum effects and gravity matter at the same time (for example inside black holes)

Basically, right now we have one set of rules for how things behave that applies to big, galactic distances… and we have a different set of rules for how things behave at smaller distances.

Both sets of rules work just fine. They’re accurate and good. They just don’t *interact*.

For a while, we had a bunch of different sets of rules. Electricity had one set of rules, magnetism had a separate set of rules, radioactivity followed a set of rules, and atomic theory had its own set of rules.

Again, these sets all worked fine, but they didn’t interact. If you had a question about why molecules formed, you could answer it, but it wouldn’t really talk about why some substances were magnetic.

It didn’t take very long for Electricity and Magnetism to be combined into a single rule set. The same stuff that made electricity work *also* explained magnetism stuff! Likewise, nuclear forces that hold atoms and molecules together could be explained within a set of rules that also explained why they sometimes decayed radioactively. So that’s another set of rules we can combine.

The last set of rules that’s still independent of all the others is **gravity**. The rules for gravity, for how planets and stars and constellations all interact, are consistent, accurate, and they work… but they don’t interact at all with electromagnetism or atomic forces.

Unified field theory is the idea that there could be a single set of rules that could effectively model *everything*, from subatomic forces up to galaxies. So far… we haven’t been able to do it.