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To be fair... the relativity of wrong supports the Lit major's point: if wrongness is relative, you probably shouldn't make binary statements along the lines of
by bbctol 10y ago
To be fair... the relativity of wrong supports the Lit major's point: if wrongness is relative, you probably shouldn't make binary statements along the lines of "previously we did not understand the basis of the universe, and now we do." Relativity is less wrong than Newtonian mechanics, but it's still fair to say Newtonian mechanics is an "incomplete" view of the universe.
- tgb 10y agoI think the biggest difference is that Newtonian mechanics tells us how forces act but it doesn't say anything at all about what forces there are. Newtonian gravitation gave one source of forces, but the rest were ad hoc: two objects don't intersect so there must be a normal force and we observe sliding objects to slow down so there must be a friction force. Now we think we have a complete list of all forces that arise, ever.
- grigjd3 10y agoIn 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.
- mikeash 10y agoI'd want to see what Asimov wrote in the original essay before saying that it supports the letter writer's point. "...We finally got the basis of the universe straight" is a brief summary of whatever was originally stated, and is only included to introduce the overall point of this essay. I would guess, since Asimov was a pretty smart fellow who understood this stuff pretty well, that the original statement was more along the lines of saying how great it was to live in an age where so many fundamental things about the universe are now understood. Things like relativity and quantum mechanics may be superseded by new things, but they'll remain fairly accurate understandings of what they're meant to describe, analogous to the spherical earth he mentions later.
- andars 10y ago"it's still fair to say Newtonian mechanics is an "incomplete" view of the universe" The arguments back and forth on this fascinate me. On one hand, on some scales, Newtonian mechanics is "correct enough" to give results that work, and so in that sense it is just "incomplete" in that its domain is restricted. On the other, relativity and QM change everything. These new theories may reduce to Newtonian mechanics given certain assumptions, but Newtonian physics says things about the structure of spacetime that are incorrect (e.g. velocity is not additive). In this sense, one can fairly say that Newton's mechanics are not just incomplete, but wrong.