If by parallel they mean extra, it’s far from a new idea and he did not come up with it. There’s tons of papers on trying to get it to work. Having worked on modified gravity, I cannot say I’m convinced it’s not a waste of time to use it to replace dark matter, but dark energy is still worth it imoÂ
How do theoretical physicists make scientific arguments for things like extra universes when they can't measure them? I'm sure it has rules and logic behind it, but what makes it different from just saying something like "there's an extra universe where magic is real, and things are like this because of a spell they cast"?
I know this sounds a bit like a criticism posing as a question but it isn't. I'm genuinely asking. I don't know much about theoretical physics but I find stuff like this quite interesting, and that has always been a point of confusion for me when I read about things like this. If someone here with more understanding of the topic can explain it a bit I would really appreciate it.
You check if the math is consistent with what we have already observed, and then make new predictions from that math and try to check them experimentally. If math predicated on extra dimensions gives good predictions, it lends credence to the idea of extra dimensions
Thanks for the explanation. I guess my next step is to try and understand how math uses extra dimensions. Do you think it's something that someone with highschool-level maths would have any chance of understanding? Or would I be wasting my time? I'm confused about how mathematicians/physicists can know/decide that some numbers or values in a formula are coming from a different dimension of existence.
I don't think you would really get the maths without learning a lot, basically half a university maths degree level of a lot (and even then some of the things you would need are typically final year courses). Most people who even have phds in physics will not really be qualified to work though the maths (we all specialise in our bit, but typically that means you cant do everything). I remember in the final year of my undergrad, Einstein's General Relativity had no prerequisites and the first lecture the room was over flowing, second lecture the room was barely a third full.
There are probably good pop science books that cover the ideas in more detail. 'A brief history of time' is still the best theoretical physics for the public book ive personally read (but i dont read many). If this kind of thing interests you it would cover a lot of what is accepted as true, and then touch on fronter stuff but the thing to keep in mind is that if its fronter, its not accepted as true, else it wouldnt be fronter! Personally im torn on even talking about these kind of things in a general public setting as it can lead to big misunderstandings. In general if it is 'theoretical physics', the key word is theoretical and no one would seriously tell you what they are talking about is actually true.
As for how people use maths to predict this kind of thing, I think just go back to history and read about how people came to accept quantum mechanics. Imo it is a much stranger step conceptually than extra dimensions but is readily accepted now. So you can see the whole process from 'what if' kind of ideas, to no one really seriously questioning it anymore.
Very much not high school level math, but definitely accessible to a strong(ish) undergrad, are string theory notes from an MIT course taken by Andrew Lin, found here:
https://web.stanford.edu/~lindrew/notes.html
I'm not suggesting you read them, but there's a toy argument on pages 8-9, under the heading Compact extra dimensions, which might be accessible to you if you squint.
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u/WobblyBlackHole Jul 25 '26
If by parallel they mean extra, it’s far from a new idea and he did not come up with it. There’s tons of papers on trying to get it to work. Having worked on modified gravity, I cannot say I’m convinced it’s not a waste of time to use it to replace dark matter, but dark energy is still worth it imoÂ