Microgravity parable

Peter Smith wrote:
I went on to explain how you could (if you were in a sealed box with no
windows and experiencing no obvious gravitational effects), how you could
differentiate between orbit and absence of (significant) gravity.

There are ways to fool the human body into thinking a plane is falling even
though it is still climbing (by gradually reducing climb rate by a certain amount).

There are ways to simulate 0g in a plane even though it isn't in orbit.

On the ISS, your senses may be fooled into thinking that there is no gravity
because you fall at the same rate as the walls, ceiling, floor. But a cell
doesn't really have senses, nor do crystals, light waves etc.

It is only in recent history that we found out that gravity also affects
light. Before that, humans thought gravity only affected "matter" and didn't
think light could be affected.

Until we understand gravity 100%, it is wrong and/or arrogant for anyone to
state that all the effects of gravity are cancelled if you are in the right
spot on the ISS.

Neelix wrote...
Until we understand gravity 100%, it is wrong and/or arrogant for
anyone to state that all the effects of gravity are cancelled if
you are in the right spot on the ISS.

Of course.

And a previous post of mine showed how to easily demontrate that they are
*not* cancelled.

- Peter

From stmx3:
Stuf4 wrote:
From stmx3:

Stuf4 wrote:
[snip]



"NASA scientists call this microgravity... The term is apt since
Albert Einstein said that acceleration caused by gravity is equivalent
to any other push."

The principle is about _mass_ equivalence, not acceleration
equivalence.


[snip]

That is incorrect. It was the happiest moment in Einstein's life when
he realized that an accelerated reference frame was equivalent to a
frame in a uniform gravitational field. From this basis, Einstein could
later show the equivalence of intertial and gravitational mass. But the
first preceded the second.


It's called a thought experiment. I suspect a primary reason is
because Einstein was well aware that there's no such thing as a
"uniform gravitational field".

Gravity follows an inverse square decay (not uniform linear decay).
Gravity extends radially (not uniformly linear once again).

These are the extremely fine ways to distinguish gravity from uniform
linear acceleration (the "moving elevator"). To repeat the easy way:

Just look out the window.


You've made this point before. This does not support your statement
that the Principle of Equivalence is about "mass-equivalence" and not
"acceleration equivalence". I was hoping to correct you on this
misconception.

Mike Hanson offered a link below with a concise explanation of the
equivalence principle. Here is a quote:

"The simplest way to state the equivalence principle is this: inertial
mass and gravitational mass are the same thing."

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

I didn't (/don't) follow your argument about "acceleration
equivalence".


~ CT

From Peter Smith:
Stuf4 wrote...

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.

Peter, please check "orbital microgravity" as a self-contradictory
oxymoron. Orbits require gravity in order to be orbits.

duuh - that's why I used the quote marks, Stuf4.

(A perfectly accurate term is "micro-g". No contradiction.)

I went on to explain how you could (if you were in a sealed box with no
windows and experiencing no obvious gravitational effects), how you could
differentiate between orbit and absence of (significant) gravity.

I agree with your point there. There are other ways to tell that an
astronaut is in a strong gravitational field (vice "zero gravity")
beside just the windows.

By the way, if you looked out the window, how would you detect a black
hole?

One way would be to observe the patch of blackness that defines the
black hole's event horizon circled by a haloed grouping of apparent
stars created by the gravitational lens effect.


~ CT

Stuf4 wrote...

By the way, if you looked out the window, how would you
detect a black hole?

One way would be to observe the patch of blackness that
defines the black hole's event horizon circled by a haloed
grouping of apparent stars created by the gravitational
lens effect.

If the Sun became a black hole, its event horison would have a 6km
diameter. To see the black disc, I would have to be at most 350km away.
At this distance the gravitational gradient would be significant, and I
would be orbiting at 1.9kHz. I would be feeling like LooseChanj is about
now I guess

Pass me a iBuzz Aldrin/i Hic!

- Peter

"Peter Smith" wrote in message
...
Pass me a iBuzz Aldrin/i Hic!

We know that Drew Carey is a space fan- after all, he named the results from
his garage brewery *Buzz* Beer!
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