Re: How could extra dimensions be tested?

On Mar 26, 8:31 pm, "STJensen" <RecreationalPo...@xxxxxxxxx> wrote:
I hear about lower and higher dimensions, but I wonder if any
scientist is currently trying to come up with a way to see if they
exist. Is anyone? If so, who and how? If not, what do scientists
speculate such a test might involve?

The above runs on the assumption that there are extra dimensions. As
far as I have heard and read, these other dimensions are speculated
about but none have been proven. Then again, have they been proven?

Scott

Ultimately we perceive three spatial and one time dimension by virtue
of the parameters we may adjust in the interaction of two objects.
[e.g. photons and your eyes.] With these parameters we construct a
four dimensional manifold of events. Your eyes and brain do this
automatically when you use parallax vision and your time sense to
distinguish the behavior of various objects such as a friend waving
his hand. But in the words of Monty Python, "it's only a model!"

One may as well consider the six or eight dimensions of phase-space.
Or the dimensions of the state manifold for a given particle
(generally a sub-manifold of phase space defined by constraints.) Are
these "real?" You can add more when you consider gauge theories... or
stick to the one dimension representing the dynamic evolution of "the
universe as it is" or the zero dimensional description of "the
universe as it is, was, and always shall be" instead of the
multiplicity of hypothetical parameters we use to describe "the
universe as it might be".

Is a 28-dimensional model better than a 42 dimensional one? Only if
it better predicts empirical phenomena. If two such models are
equivalent at prediction which is the "real number of dimensions"?
Does the question have any meaning?

When a physicist counts dimensions he is counting within a model.
When a 'good' physicist uses a model he does not assert that it
represents "reality as it is" but rather that it is "a good model for
predicting empirical phenomena". Theories are systems of prediction
and models can be thought of as conceptual scaffolding used to hold
the pieces of the theory in place. Modern science isn't about "the
universe as it is" but about "the behavior of empirical phenomena".
Models are a tool in this description but properties of the tools are
not the same thing as physical laws.

String/Brane theorists are playing with modeling objects as sub-
manifolds within larger dimensional spaces. If they are good
physicists they shouldn't take these extra dimensions too seriously as
"what's real" and stick to the question of whether their model
predicts phenomena well. And so too should the rest of us.

So ultimately I would say that the number of dimensions "which exist"
is unbounded as their existence occurs in the mind and not in the
laboratory.

Regards,
James Baugh

.

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