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In particular to the question at hand Newtonian physics has a very hard time explaining the galactic and super-galactic structure we see. Without relativity, da
by grigjd3 10y ago
In particular to the question at hand Newtonian physics has a very hard time explaining the galactic and super-galactic structure we see. Without relativity, dark matter, and dark energy, those structures are not clear conclusions and certainly Newtonian gravity does not arrive at those conclusions. I think it very fair that Asimov points to the 20th century as where we sussed out the structure of space.
- evanb 10y agoI think you mean astrophysical, rather than galactic? Galactic structures are well-explained by Newtonian gravity (assuming dark matter, but that's independent of whether you describe gravity as Newton or Einstein did). Large-scale structure, too, I thought. Compact objects---black holes, quasars, neutron stars, etc---and details of the galactic core need GR. But you get it mostly right without it, I thought.
- grigjd3 10y agoThe point is that dark matter is still a 20th century theory, meaning that the structure of galaxies is understood only with 20th century theories. If you read the letter carefully, you'll find that was the original claim made by Asimov.