The deterministic universe theory

< In science there is a theory that we are not real. Not in the simulation sense (mostly) but in the sense that atoms reacting with each other to make everything. Personally I believe and have come to terms with the fact that our universe is deterministic. Me as a person is just a bunch of neurons firing in my brain from photons in my eyes and signals from my body. Even that is not the end of it because there are atoms making up those neurons and quarks making up the atoms and who knows how much further it goes.
Now to get into the part that I love about the theory, we could simulate it, though it would take an unimaginably long time to calculate even 1 frame. Now the way that this could be made is with a cellular automata but let me put into perspective how hard this is. for reference in order to make an accurate enough simulation you would need to make 1 grids side lengths the Planck length. If you don't know what the Planck length is it is the smallest point you can get too before physics breaks down:
The Planck length is 1.616255 x 10^-35 which written out is 0.00000000000000000000000000000000001616255 meters
So you would need to calculate grid squares at this size but they also need to be the size of the universe long, tall, and wide. Which is too much for a human to comprehend but think of it this way, if one of our computers tried to simulate this that computer would both explode and run at roughly 0 frames a year.
Anyway, there is a really good kurzgesagt about this topic and also that y'all for reading and have a great rest of your day :)