Re: Dark Matter = discrete acceleration spectrum?
- From: "Mike" <no.spam@xxxxxxxxxx>
- Date: Wed, 31 Oct 2007 05:51:32 +0000 (UTC)
<ebunn@xxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:ffnc04$no1$1@xxxxxxxxxxxxxxxxxxxxxxx
In article <471b8756$0$7211$6d2eeca5@xxxxxxxxxxxxxx>,
Mike <no.spam@xxxxxxxxxx> wrote:
What effect of Dark Matter can there be that cannot also be explained by
a discrete spectrum of acceleration?
What you say is quite vague and hard to pin down. But I think the root
of the problem is confusion of two meanings of the word "quantized."
"Quantized" can mean "allowed to take on only discrete values" (as when
we say, for instance, that the energy levels of a hydrogen atom are
quantized). This is apparently what you have in mind when you talk about
a discrete spectrum of acceleration.
But quantized can also mean "described by a quantum theory," which is
not the same thing. For instance, when we say that the electromagnetic
field is quantized, it does not mean that there are only a discrete set
of electromagnetic field values that are allowed. It doesn't even mean
that only a discrete set of energies are possible -- in the quantum
theory of electromagnetic fields, a single photon can have any positive
amount of energy.
When we theorize that gravity is quantized, we mean the latter idea, not
the former one. In particular, there's no reason to suspect that
quantum gravity will lead to a discrete spectrum of possible
accelerations (just as we don't have a discrete spectrum of electric
field values in electromagnetism). In *some* quantum theories of
gravity, *some* measurable quantities are quantized in the sense of
having discrete spectra, but not generally acceleration, as far as I
know.
-Ted
You might be right, I don't know. I was noticing the possible use of the
equivalence principle in quantum gravity. There's lots we don't know yet.
As I understand it Loop Quantum Gravity is suppose to derive a minimum
length scale. But what is more interesting is that we would be considering
how mass moves in a quantum gravity theory. And I'm not sure that any
quantum gravity theories adequately incorporate particles yet.
.
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