And, not so much funny 'ha-ha' as funny 'hmmmm', apparent astronomical evidence of the existence of large pockets of dark matter. I'm very skeptical about concepts like Dark Energy and Dark Matter: just like string theory, they upset my notion that in order to qualify as science, a theory damn well ought to be testable. To explain the problem of cosmological reacceleration (the fact that the rate of cosmological expansion, in the wake of the Big Bang, slowed for several billion years, then started to accelerate again), I prefer theories of Modified Newtonian Dynamics.
Traditional Newtonian Laws of Dynamics are just approximations, which quantum laws approach as you change the scale from the micro to the macro (the so-called Correspondence Principle). You need quantum mechanics to describe the actions of a single electron, but if you start talking about amps of current flowing through a resistor, traditional electrodynamics do the job just fine.
Similarly, MOND posits that our traditional law of gravity is also just an approximation, perfectly describing the behavior of balls falling through air, or planets flying around a sun. But when you start to talk about extremely large distances, like that between various galaxies, maybe the rules change a bit. That could explain the reacceleration in a way that avoids having to propose that we don't know where 95% of the mass-energy of the Universe is hiding, as dark matter/dark energy theories claim.
Anyhow, my point is just that if, as claimed, we've seen some real evidence for the existence of dark matter (large pockets of mass whose existence we can presume from experimental evidence, although we cannot see it directly), that is a big feather in the cap of Dark Matter/Energy theorists.
Like any good modern physics argument, this one probably won't be solved anytime soon. But it's something worth keeping an eye out, at least if you are one of the 14 or so people not actually working in the field who still cares about this stuff.
Subscribe to:
Post Comments (Atom)
1 comment:
It is my impression, from Cosmic Variance and other sources, that we do have some evidence which supports the dark energy and matter hypotheses. Maybe this isn't strictly the result of a prediction, but it seems at least close.
Granted, I know little about it.
Further illustrating my ignorance of cosmology: does MoND have anything to say about the preservation of structures like spiral galaxies? I was under the impression that without postulating something like dark matter, it's hard to explain how such structures could persist for as long as they have; i.e., one would expect them to fly apart much more quickly, if they were only bound by the gravity of observable matter.
Post a Comment