- #36

bhobba

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weirdoguy said:Maybe because most people who knows technical details of both dark matter models and alternative models think that dark matter models are better and simpler?

That's it, really. GR as we know it is almost inevitable because of Lovelock's Theorem. In layman's language, it says, basically, if our knowledge of the theory of fields is correct (technically, it is assumed it can be derived from a Lagrangian - a generalisation of ordinary mechanics), Einsteins Equations are inevitable. Of course, we know that GR needs modification at small scales - about the Plank Scale - because of issues with QM. But we even have a quantum theory of gravity thought to be correct to the Plank Scale:

https://blogs.umass.edu/donoghue/research/quantum-gravity-and-effective-field-theory/.

It is also thought the Standard Model breaks down at the Plank Scale - possible even before. So that is nothing new, really.

Anyway, the bottom line is if GR were not true, some longstanding physical principles would have to be wrong. That is indeed possible, but so far, nobody has come up with an alternative that is just so damn elegant, requires so few assumptions and stands up to experimental verification. Lev Landau was fond of saying, 'a rapture on first making one's acquaintance with this theory should, in general, be a characteristic of any born theoretical physicist.'

Thanks

Bill