Recent content by Pyter

With that model, has it been said in the previous posts that the observed CMB should stop at one time, since there's no infinite matter from which it might come from?

In maths this is legal: ## 2\delta(x) - \delta(x) = \delta(x) ## . Perhaps also in physics, in branches other than cosmology apparently. So there's currently no cosmological model based on finite matter/energy, at least no one able to explain the CMB convincingly?

In that case the accepted CMB explanation starts to make sense to me. But this "infinite matter" model is at odd with other cosmology notions I've gleaned, namely the enigma of the prevalence of matter over antimatter. As you surely know, it is argued that at the beginning they should've been...

So right after the BB, let's say one Planck time interval after, there already was infinite matter spanning infinite 3D Euclidean space (assuming the flat space model holds)?

In that model, that for me is easier to visualize than the others, what is it that "expands" after the BB?

By "universe" do you mean the energy/matter present in the universe, or the empty space? I thought that there was also a model contemplating a finite amount of matter expanding in a flat, infinite 3D Euclidean space.

I'm jumping on this thread because I never fully grasped the CMBR too. For instance, I was wondering: did the whole matter in the Universe cool down to the Mott's temperature at the same instant, or did the outer layers cool first, then the inner ones, up to the the core?

The exact name for this phenomenon is Inharmonicity. But the Wikipedia article only explains it qualitatively, not with a rigorous mathematical treatment. This is also the reason why the pianos are tuned with stretched octaves.

It could be so if the amount of saddle adjustment were proportional to the string's diameter, but this isn't always the case.

One thing I've always wanted to discuss about: why do you have to adjust the scale of the single string individually? I mean if you tune all the free strings to exact pitch and adjust the saddles at the bridge all flush, then you play them at the 12th fret, some sound flat and some sharp with...

@hutchphd you're right. So I guess this answers question c).

I also thought about that, but actually when you do it, for instance at the 12th fret, you play the same note as the fully pressed string, only with a different timbre (overtones).

The question isn't very clear. Does it ask if it only produces the fundamental mode? Because the fundamental mode is always produced, together with the overtones. I'm not sure about that one, shouldn't it be ##\omega = \sqrt {\frac {T} {\mu} } ## for analogy with the harmonic oscillator?

Of course, I was talking about MKS units.

Right. But not ##c^2##, I guess? Otherwise either the RHS of the line element is not dimensionally correct, or ##g_{tt}## has a dimension different from ##g_{rr}##.