Dr. Sutter makes a number of other interesting points. He says we shouldn’t
pick [a hypothesis] that sounds cooler or seems simpler. I’m not sure which seems cooler here – a universe pervaded by a mysterious invisible mass that we can’t [yet] detect in the laboratory but nevertheless controls most of what goes on out there seems pretty cool to me. That there might also be some fundamental aspect of the basic theory of gravitational dynamics that we’re missing also seems like a pretty cool possibility. Those are purely value judgments.Simplicity, however, is a scientific value known as Occam’s razor. The simpler of competing theories is to be preferred. That’s clearly MOND: we make one adjustment to the force law, and that’s it. What we lack is a widely accepted, more general theory that encapsulates both MOND and General Relativity.
First, remember some history. When Newton introduced his inverse square law of universal gravity, it was promptly criticized as a form of magical thinking: How, Sir, can you have action at a distance? The conception at the time was that you had to be in physical contact with an object to exert a force on it. For the sun to exert a force on the earth, or the earth on the moon, seemed outright magical. Leibnitz famously accused Newton of introducing ‘occult’ forces. As a consequence, Newton was careful to preface his description of universal gravity as everything happening as if the force was his famous inverse square law. The “as if” is doing a lot of work here, basically saying, in modern parlance
Stacy McGaughOK, I don’t get how this is possible, I know it seems really weird, but that’s what it looks like.I say the same about MOND: galaxies behave as if MOND is the effective force law. The question is why.
I must admit I haven’t paid too much attention to this particular conundrum in astrophysics because, as with many current topics in advanced physics, there doesn’t seem to be much tangible progress to follow. But I found the arguments of this article in favor of at least thoroughly researching MOND compelling. Preliminary results from the JWST, finding evidence of multiple, evolved galaxies much earlier in the history of the universe than current models predict, may also support MOND, or at least some revision of our understanding of cosmology.
The theory’s main disadvantage is its incompatibility with Einstein’s General Relativity, which has yet to fail a single test on cosmological scales and in our own solar system. Perhaps General Relativity’s most mysterious component, the cosmological constant, may prove a bridge between these two conflicting theories; if the cosmological constant is not, well, constant, instead exhibiting subtle changes on large distances or depending on the density of intergalactic space, it might explain the gravitational dynamics captured by MOND.
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