Complex Numbers

Fearful Symmetry

Today's link is just some really cool theoretical physics.

https://www.quantamagazine.org/how-simple-rules-bootstrap-the-laws-of-physics-20...

Why the Laws of Physics Are Inevitable
By considering simple symmetries, physicists working on the “bootstrap” can rediscover the basic form of the known forces that shape the universe.

Fear not; there's no advanced math in here. This is mostly of philosophical interest. One of the questions I keep seeing in physics is, "Why is there something rather than nothing?" Though that seems to me that it might be asking the wrong question; after all, if there were nothing, we wouldn't be around to ask the question.

To an astonishing degree, nature is the way it is because it couldn’t be any different.

That's probably the answer to the question that they didn't ask. For a long time, I've seen speculation that other universes might exist, somewhere, with different laws of physics. This seems to suggest that can't be the case.

Since the 1960s, and increasingly in the past decade, physicists like Baumann have used a technique known as the “bootstrap” to infer what the laws of nature must be.

It's satisfying when you can come at a question from different angles and get the same result.

That solution is the graviton: a spin-2 particle that couples to itself and all other particles with equal strength.

I'm no expert on these things, but my understanding is that, so far, the graviton is a purely theoretical particle. Physicists have been proposing it for some time, because it would imply quantum gravity, which in theory could bridge general relativity and quantum mechanics, perhaps leading to a Grand Unified Theory, kind of the Holy Grail of physics.

Of course, assuming they find this Holy Grail ("I told him we already got one"), it'll probably just raise more questions. This is why science is fun.

It’s “just aesthetically pleasing,” Baumann said, “that the laws are inevitable — that there is some inevitability of the laws of physics that can be summarized by a short handful of principles that then lead to building blocks that then build up the macroscopic world.”

Complexity emerging out of simplicity just makes so much more sense than the other way around, don't you think?