Microgravity parable

From Herb Schaltegger:

How ironic that you offer your extrapolation regarding "pretty much
everyone..." while chastising my extrapolation.

This reads as another form of "I'm right/you're wrong", coated with a
heavy tinge of hypocrisy.

And how many posters are publicly supporting your continued games of
semanticism, pedantry, prevarication, equivocation and hand-waving?
None.

But let me guess: the lurkers all support you in email.

Umm, they're not lurking.

Then where are your supporters? Your detractors have had no qualms
about telling you when you're completely out in left field.

All I was saying was that one particular member has a published
webpage that stands in complete agreement with the position I have
been presenting.

(If you really care about my email, I have not gotten any email
support on this. I may have when this topic came up a couple of years
ago, but I don't remember.)

If you've been following the thread
thoroughly you've seen that Jim Oberg's website has a page that fits
in total agreement with what I've been saying here.

So if, by assumption, Jim agrees with the position I have put forward,
one might ask why he has remained silent.

Perhaps he's got you killfiled? Perhaps he has more interesting things
to do these days on the eve of a manned Chinese launch. (And please
spare us any tedium regarding Webster's definition of "eve.")

If anything I post strikes you as tedium, you are free to ignore it.

(3rd Reich lessons learned have previously been provided as to their
application here at sci.space.)


Watch who you're calling a Nazi; Uncle Ashcroft's Patriot Act Though
Police might come tracing your IP address and subpoena your name and
address.

Another excellent example of US government encroachment on the US
Constitution.

But I expect that John Ashcroft is a competent enough attorney to
distinguish between a statement that "lessons were learned in studying
the Nazi's" versus a statement "(whoever) IS a Nazi".


~ CT

From Scott Hedrick:
"Stuf4" wrote in message
om...
Umm, they're not lurking. If you've been following the thread
thoroughly you've seen that Jim Oberg's website has a page that fits
in total agreement with what I've been saying here.

Please provide verifiable references to a post in which Jim Oberg has
expressly stated that he agrees with your position that NASA engineers do
not understand the concept of gravity. For that matter, why not simply ask
publically, right here, if Jim supports you on that specific point?

So if, by assumption

Well, we all know what happens when *you* make an assumption...

I would agree that there's not much point in me making assumptions on
what views other people hold in regards to this topic. And I don't
see much point in me trying to research references toward any
particular person's views.

All of this illustrates the futility of science by popularity contest.

If 6 billion people were to hold the same view while one lone person
holds an incompatible view, those numbers do nothing to prove anything
for either side. It is conceivable that the 6 billion are in error
while one person holds an accurate view.


~ CT

From Herb Schaltegger:

How ironic that you offer your extrapolation regarding "pretty much
everyone..." while chastising my extrapolation.

This reads as another form of "I'm right/you're wrong", coated with a
heavy tinge of hypocrisy.

And how many posters are publicly supporting your continued games of
semanticism, pedantry, prevarication, equivocation and hand-waving?
None.

But let me guess: the lurkers all support you in email.

Umm, they're not lurking.

Then where are your supporters? Your detractors have had no qualms
about telling you when you're completely out in left field.

All I was saying was that one particular member has a published
webpage that stands in complete agreement with the position I have
been presenting.

(If you really care about my email, I have not gotten any email
support on this. I may have when this topic came up a couple of years
ago, but I don't remember.)

If you've been following the thread
thoroughly you've seen that Jim Oberg's website has a page that fits
in total agreement with what I've been saying here.

So if, by assumption, Jim agrees with the position I have put forward,
one might ask why he has remained silent.

Perhaps he's got you killfiled? Perhaps he has more interesting things
to do these days on the eve of a manned Chinese launch. (And please
spare us any tedium regarding Webster's definition of "eve.")

If anything I post strikes you as tedium, you are free to ignore it.

(3rd Reich lessons learned have previously been provided as to their
application here at sci.space.)


Watch who you're calling a Nazi; Uncle Ashcroft's Patriot Act Though
Police might come tracing your IP address and subpoena your name and
address.

Another excellent example of US government encroachment on the US
Constitution.

But I expect that John Ashcroft is a competent enough attorney to
distinguish between a statement that "lessons were learned in studying
the Nazi's" versus a statement "(whoever) IS a Nazi".


~ CT

(Stuf4) wrote in message . com...

snip
- Gravity is *distinctly different* from acceleration.

While gravity has a property of acceleration, it is *not*
acceleration. A 'g' is a unit of acceleration standardized upon a
particular case of acceleration due to gravity (the gravitational
acceleration at the surface of the Earth).
snip

I haven't posted here for a while; I just took a look, came across
this interesting-looking thread title, and then read the above
statement. You appear to have mangled your terms somewhat:

Gravitation is certainly not the same thing as acceleration. Gravity,
on the other hand, is locally indistinguishable from acceleration. The
fact that this is so led Einstein to apply Occam's razor and postulate
that the two are in fact one and the same phenomenon, leading to
general relativity. GR has yet to be falsified. We may therefore say
that, to the best of our knowledge, gravity and acceleration are the
same thing and that NASA is correct in its use of the letter g.

Mike.

(Stuf4) wrote in message . com...

snip
- Gravity is *distinctly different* from acceleration.

While gravity has a property of acceleration, it is *not*
acceleration. A 'g' is a unit of acceleration standardized upon a
particular case of acceleration due to gravity (the gravitational
acceleration at the surface of the Earth).
snip

I haven't posted here for a while. Decided to take a look, saw an
interesting-looking thread title, and came across the above statement.
You appear to have mangled your terms somewhat:

*Gravitation* is distinctly different from acceleration.

Gravity, however, is locally *indistinguishable* from acceleration.
That this is so led Einstein to apply Occam's razor and postulate that
they are one and the same phenomenon, leading to general relativity.
And since GR has yet to be falsified, one can say that, to the best of
our knowledge, gravity and acceleration are indeed the same thing (and
hence that NASA is correct in its use of the letter g).

Mike.

My apologies for the double-post - Google trouble.

Mike.

From Mike Hanson:
(Stuf4) wrote

snip
- Gravity is *distinctly different* from acceleration.

While gravity has a property of acceleration, it is *not*
acceleration. A 'g' is a unit of acceleration standardized upon a
particular case of acceleration due to gravity (the gravitational
acceleration at the surface of the Earth).
snip

I haven't posted here for a while. Decided to take a look, saw an
interesting-looking thread title, and came across the above statement.
You appear to have mangled your terms somewhat:

*Gravitation* is distinctly different from acceleration.

Gravity, however, is locally *indistinguishable* from acceleration.
That this is so led Einstein to apply Occam's razor and postulate that
they are one and the same phenomenon, leading to general relativity.
And since GR has yet to be falsified, one can say that, to the best of
our knowledge, gravity and acceleration are indeed the same thing (and
hence that NASA is correct in its use of the letter g).

This point regarding the equivalence theory has been addressed more
than once on this thread...

One easy way to determine whether you are accelerating due to gravity
or not is to look out the window of your spacecraft to see if there
are any stars or planets nearby.

(I've suggested elsewhere that the root of this confusion in
terminology is a misunderstanding of the equivalence principle.)


~ CT

(Stuf4) wrote in message om...
From Mike Hanson:
(Stuf4) wrote

snip
- Gravity is *distinctly different* from acceleration.

While gravity has a property of acceleration, it is *not*
acceleration.
snip

*Gravitation* is distinctly different from acceleration.

Gravity, however, is locally *indistinguishable* from acceleration.
snip

This point regarding the equivalence theory has been addressed more
than once on this thread...

One easy way to determine whether you are accelerating due to gravity
or not is to look out the window of your spacecraft to see if there
are any stars or planets nearby.

You misunderstand. First of all, one does not 'accelerate due to
gravity': objects in freefall do not accelerate by definition, since
they are inertial (no forces act upon them). Instead, objects in
freefall travel in what is commonly described as a 'straight line in
curved spacetime'. This is hard for many people to accept because
Newtonian physics - which is very intuitive and taught to most people
at school - describes gravity as a force. There is no such voodoo-like
force-at-a-distance in general relativity.

Instead, the forces and accelerations being referred to are scrictly
local ones. Standing on the ground, a man has weight: he feels a force
pushing up on the soles of his feet. Out in space and accelerating at
9.81 m/s^2, the man also has weight: he feels exactly the same force
pushing up on the soles of his feet. These two 'forms' of weight are
qualitatively identical, and this is where you have gone wrong:
looking out of the window doesn't count. The key word is 'locally',
and the question is: can you distinguish between the first and second
cases *if you don't know where you are*? And the answer is: no.

(I've suggested elsewhere that the root of this confusion in
terminology is a misunderstanding of the equivalence principle.)

You are right. This may help (and look out for the word 'local'):

http://www.npl.washington.edu/eotwash/equiv.html

Mike.

Stuf4 wrote:
[snip]

All of this illustrates the futility of science by popularity contest.

If 6 billion people were to hold the same view while one lone person
holds an incompatible view, those numbers do nothing to prove anything
for either side. It is conceivable that the 6 billion are in error
while one person holds an accurate view.


~ CT

"Stuf4, party of 1, your table is ready. Stuf4, party of 1..."
:-)

Mike Hanson wrote...
Out in space and accelerating at
9.81 m/s^2, the man also has weight: he feels exactly the
same force pushing up on the soles of his feet. These two
'forms' of weight are qualitatively identical, and this is
where you have gone wrong: looking out of the window
doesn't count. The key word is 'locally', and the question
is: can you distinguish between the first and second
cases *if you don't know where you are*? And the answer is: no.

You ask whether one can distinguish between gravity and acceleration. But
the question of whether one can distinguish between 'orbital microgravity'
and a 'microgravity field' is a different question.

It's interesting that one can make this distinction by observing a
'floating' particle which is tapped very lightly. In orbit, the particle
will oscilate in space when tapped (when the movement is viewed over an
orbital period), in a freefall or microgravity field the particle will
continue in a straight line. (Using local frames of reference of course.)

Those with a better understanding of orbital mechanics will no doubt tidy
up my post.

- Peter