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Re: [Phys-L] gravitational waves



1) I still think that avoiding general relativity, in an explanations of gravitational waves to elementary physics students, is desirable, at least as the first step of the explanations.

2) The distance x, (between the two disk-like pistons in my model), changes because the the source disk is oscillating. The gravitational wave intensity, the amplitude of g(t), at any given x, is inversely proportional to the x^2, according to N2. The measured g(t) were vary small, in comparison with 9.8, m/s^2, because the x are usually very large.

Ludwik Kowalski.

===============================


On Apr 3, 2016, at 1:30 PM, Ludwik Kowalski wrote:

Thank you again. The variable gravitational field g(t) is an essential component of my trivial model.

Ludwik
============================================

On Apr 3, 2016, at 11:59 AM, John Denker wrote:

There is a proverb that says:
If you are allergic to bread, cheese, and tomatoes,
don't order pizza.

Also: Just because somebody asks a question doesn't mean
you have to answer it. If the question doesn't make sense,
change the subject.

I mention this because on 04/02/2016 08:29 PM, Ludwik Kowalski wrote:

I believe you that explaining gravitational waves in
terms of Newtonian g field is likely to give wrong answers to some
quantitative questions.

But I am not asking such questions, I am trying to explain
gravitational waves qualitatively, to people like educated laymen,
first year college students, etc.

1a) Qualitatively, gravitational waves have to do with
waves and with gravitation.

1b) Relativistic causality tells us that the classical law
of universal gravitation cannot possibly be correct. That
is to say, we cannot have action at a distance, yet that
law has an "r" variable but no "t" variable.

In contrast, any correct law must provide for a change in
the field to propagate at some speed, either c (as with
light) or less (as with sound). This is pretty much why
the concept of /field/ was invented, a field that is not
just a mathematical abstraction but a first-class physical
object.

There's not one layman in a million who needs to know
about gravitational waves in more detail than that.

2) If they demand more details about gravitational waves,
I suggest deflecting that question and instead taking the
opportunity to explain something about gravitation, fields,
and/or waves.

Rather than answering the big question incorrectly, it is
better to answer a smaller question correctly, especially
if it is a good solid step along the path towards the big
question.

If they demand a detailed mechanistic explanation of
gravitational waves but aren't interested in gravitation,
fields, or waves, they cannot possibly be serious.

If you are allergic to bread, cheese, and tomatoes,
don't order pizza.

===============

This sort of thing comes up a lot.
-- It is routine to get questions about "waves versus
particles" from people who have no idea what a wave
is, and no idea what a particle is.
-- It is routine to get questions about "Higgs bosons"
from people who have no idea what a boson is, and no
idea what a mass gap is.
-- It is routine to get questions about "degeneracy
pressure" from people who have no idea what degeneracy
is, and no idea what pressure is.
-- et cetera...........

In all such situations, I tell people that I'm not
superman, and they're not either. I cannot teach them
to leap tall buildings at a single bound. I can however
show them where the stairwell is, and we can climb up
step by step.
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_______________________________________________
Forum for Physics Educators
Phys-l@www.phys-l.org
http://www.phys-l.org/mailman/listinfo/phys-l