all physics teachers and lecturers should make clear to their students
that nothing physical, such as time, the spectrum of electromagnetic
waves and so forth, can be shown to be continuous. it is not possible
to show that something is continuous by measurement because of the
dependence on infinity in the definition of continuity. to many people
seem to take for granted that time is continuous, same thing with the
spectrum of light. they should instead say that everything is probably
quantized or something like that.

wrote:
all physics teachers and lecturers should make clear to their students
that nothing physical, such as time, the spectrum of electromagnetic
waves and so forth, can be shown to be continuous. it is not possible
to show that something is continuous by measurement because of the
dependence on infinity in the definition of continuity. to many people
seem to take for granted that time is continuous, same thing with the
spectrum of light. they should instead say that everything is probably
quantized or something like that.

There's a difference between telling students that measurements have
some finite accuracy and concluding therefrom that all things are,
objectively, discrete.

Is space-time discrete? Maybe. Maybe not. Do you have a fact-based
theory which requires discrete space-time, and is in a testable form?

-Mark Martin

In article .com, writes:
all physics teachers and lecturers should make clear to their students
that nothing physical, such as time, the spectrum of electromagnetic
waves and so forth, can be shown to be continuous. it is not possible
to show that something is continuous by measurement because of the
dependence on infinity in the definition of continuity.

OK.

to many people
seem to take for granted that time is continuous, same thing with the
spectrum of light. they should instead say that everything is probably
quantized or something like that.

Really. And you know this how? According to your logic, since we
can't support with actual certainty that something is one specific
way, we should say that it is probably some other way (for which we've
no support either). This is nonsense.

We know that the properties of some entities, such space and time, are
consistent with said entities being continuous, based on current
information. And that's all we know. Physics doesn't give you
certainties, only best models consistent with available information.
You're not going to get more.

Mati Meron | "When you argue with a fool,
| chances are he is doing just the same"

wrote:

all physics teachers and lecturers should make clear to their students
that nothing physical, such as time, the spectrum of electromagnetic
waves and so forth, can be shown to be continuous. it is not possible
to show that something is continuous by measurement because of the
dependence on infinity in the definition of continuity. to many people
seem to take for granted that time is continuous, same thing with the
spectrum of light. they should instead say that everything is probably
quantized or something like that.

Everything is not discrete: the energy spectrum of a free particle is
continuous in quantum mechanics. Continuum mechanics, quantum
electrodynamics and general relativity all postulate continuous (in
space,time and momentum) fields, AFAIK.

Why do you assume everything is discrete? Why do you assume that
because the energy spectra of bound particles (or quasiparticles) is
discretized, it must follow that other quantity is similarly discretized?

Just beacuse we can define a unit of time or space (Planck time, Planck
length) that does not mean that time or space is discrete, just that the
quantum picture is not adequate to discribe features smaller than these
units. If all you had to describe length was an unmarked meter stick,
you would not assume that sub-meter lengths do not exist. Same for a
clock with a period of 1 second.

--
Andrew Resnick, Ph.D.
Department of Physiology and Biophysics
Case Western Reserve University

On a sunny day (29 Sep 2005 09:31:27 -0700) it happened "Mark Martin"
wrote in
.com:
Is space-time discrete? Maybe. Maybe not. Do you have a fact-based
theory which requires discrete space-time, and is in a testable form?
Oh yes, on my digital clock time increments in one minute quanta :-)

..

Why do you assume everything is discrete? Why do you assume that
because the energy spectra of bound particles (or quasiparticles) is
discretized, it must follow that other quantity is similarly discretized?

Just beacuse we can define a unit of time or space (Planck time, Planck
length) that does not mean that time or space is discrete, just that the
quantum picture is not adequate to discribe features smaller than these
units. If all you had to describe length was an unmarked meter stick,
you would not assume that sub-meter lengths do not exist. Same for a
clock with a period of 1 second.

what about superstrings ? are they discrete or continuous ?
are they still taken seriously ?

Jan Panteltje wrote:
On a sunny day (29 Sep 2005 09:31:27 -0700) it happened "Mark Martin"
wrote in
.com:
Is space-time discrete? Maybe. Maybe not. Do you have a fact-based
theory which requires discrete space-time, and is in a testable form?

Oh yes, on my digital clock time increments in one minute quanta :-)

Mygodyourright!!!

-Mark Martin

wrote:

all physics teachers and lecturers should make clear to their students
that nothing physical, such as time, the spectrum of electromagnetic
waves and so forth, can be shown to be continuous.

Gravitation. Time.

it is not possible
to show that something is continuous by measurement because of the
dependence on infinity in the definition of continuity. to many people
seem to take for granted that time is continuous, same thing with the
spectrum of light. they should instead say that everything is probably
quantized or something like that.

Yeah, "or something like that." Both time and gravitation are
continuous in all measurements until demonstrated otherwise.
Quantized bounce heights of cryogenic neutrons are Fermi-exclusion
stacking of neutron energies in a gravitational well.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf

blackboab wrote:
.

Why do you assume everything is discrete? Why do you assume that
because the energy spectra of bound particles (or quasiparticles) is
discretized, it must follow that other quantity is similarly discretized?

Just beacuse we can define a unit of time or space (Planck time, Planck
length) that does not mean that time or space is discrete, just that the
quantum picture is not adequate to discribe features smaller than these
units. If all you had to describe length was an unmarked meter stick,
you would not assume that sub-meter lengths do not exist. Same for a
clock with a period of 1 second.


what about superstrings ? are they discrete or continuous ?
are they still taken seriously ?

I haven't the slightest idea. I presume the bound states are quantized.


--
Andrew Resnick, Ph.D.
Department of Physiology and Biophysics
Case Western Reserve University

Andy Resnick wrote:
Everything is not discrete: the energy spectrum of a free particle is
continuous in quantum mechanics. Continuum mechanics, quantum
electrodynamics and general relativity all postulate continuous (in
space,time and momentum) fields, AFAIK.

continuous how? Given energies have given lengths.

Why do you assume everything is discrete? Why do you assume that
because the energy spectra of bound particles (or quasiparticles) is
discretized, it must follow that other quantity is similarly discretized?

Just beacuse we can define a unit of time or space (Planck time, Planck
length) that does not mean that time or space is discrete, just that the
quantum picture is not adequate to discribe features smaller than these
units. If all you had to describe length was an unmarked meter stick,
you would not assume that sub-meter lengths do not exist. Same for a
clock with a period of 1 second.

http://groups.google.com/group/sci.p...365b26703d0632

Where there are no forces, there is nothing and nothing to be
continuous about. Being that there is no weaker force than gravity
(look up "New Model") to set a biggest resonant scale (look up
"Planckian fun"), there is nothing smaller except in principle.

-Aut