Microgravity parable

On 8 Oct 2003 17:41:25 -0700, in a place far, far away,
(Stuf4) made the phosphor on my
monitor glow in such a way as to indicate that:

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

Verifiable reference, please. Not just the name of a book, please provide
the specific page and a quote.

I just found this page that gives a good set of q/a's:

http://amos.indiana.edu/library/scri...rogravity.html

Excerpts:

"...there's no such thing as zero gravity."

"...weightlessness and zero gravity are two different things."

Which doesn't mean that gravity is not acceleration. Nice diversion,
though.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
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"Rand Simberg" wrote in message

Which doesn't mean that gravity is not acceleration. Nice diversion,
though.

Gravity is a force - the weakest of the four fundamental forces
(gravitational, electromagnetic, weak, and strong IIRC). The [gravitational]
force *causes* acceleration. Gravity is not acceleration. The value for the
acceleration *due*to*gravity* at sea level on earth is about 32.2 fps^2.

Jon

On Wed, 8 Oct 2003 21:06:56 -0500, in a place far, far away, "Jon
Berndt" made the phosphor on my monitor glow
in such a way as to indicate that:

"Rand Simberg" wrote in message

Which doesn't mean that gravity is not acceleration. Nice diversion,
though.

Gravity is a force - the weakest of the four fundamental forces
(gravitational, electromagnetic, weak, and strong IIRC). The [gravitational]
force *causes* acceleration. Gravity is not acceleration. The value for the
acceleration *due*to*gravity* at sea level on earth is about 32.2 fps^2.

Well, if one wants to get pedantic, gravity is a quantitative
mathematical model invented by Newton to explain why apples fall from
trees and planets orbit suns.

In any event, the effect of it is an acceleration, something that
Stuffy seems to want to deny, or at least obfuscate.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers:

On 8 Oct 2003 17:41:25 -0700, in a place far, far away,
(Stuf4) made the phosphor on my
monitor glow in such a way as to indicate that:

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

Verifiable reference, please. Not just the name of a book, please
provide
the specific page and a quote.

I just found this page that gives a good set of q/a's:

Why don't you provide a verifiable reference to the source you used *at the
time* you first posted this nonsense? Trying to Google a source after the
fact won't help you.
--
If you have had problems with Illinois Student Assistance Commission (ISAC),
please contact shredder at bellsouth dot net. There may be a class-action
lawsuit
in the works.

From Alan Baker:
snip
And when astronauts came back from space, they would be crystal clear
that while they floated around, with their bodies having no relative
acceleration in relation to their spacecraft, gravity never came
anywhere close to zero at any point in their trip. They *never*
experienced zero gravity. They experienced zero acceleration.

They didn't even experience that. They were accelerating; it's just that
everything around them was accelerating at the same rate.

I took Joe's rebuttal as a correction. But your rebuttal, Alan, is
helping me to see accuracy in the original statement...

The word -experience- carries subjectivity. What you experience
hinges upon your -frame of reference-. From the astronauts point of
view, the point of view of their non-inertial reference frame of the
spacecraft that is affected by gravitational acceleration, the
experience is zero relative acceleration.


So let's say, for the sake of argument here, that we are agreed that
it is accurate to say that they _experienced_ zero acceleration. An
obviously salient question follows...

Could we not, by the principle of equivalence (gravitational mass
being equivalent to inertial mass) therefore conclude that this
experience of zero relative acceleration be equivalent to a statement
that:

They experienced zero gravity?

The answer might be yes, except for one showstopper. Unlike
Einstein's famous "elevator" thought experiment, it is quite possible
to determine that the spacecraft is in the gravitational field of the
planet (and Sun and Moon, etc). The most simple way to do this is to
look out the window.

(Einstein's principle here was addressed on an earlier thread a few
days ago.)


~ CT

In article ,
h (Rand Simberg) wrote:

On 8 Oct 2003 10:19:49 -0700, in a place far, far away,
(Stuf4) made the phosphor on my
monitor glow in such a way as to indicate that:


- Gravity is *distinctly different* from acceleration.

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

Your continued repetition of this statement does not make it true.

No.

The fact that it's true is what makes it true.

Gravity is *not* acceleration.

Gravity is a *force* that sometimes *causes* accelerations.

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling 4 feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect
if you sit in the bottom of that cupboard."

On Thu, 09 Oct 2003 05:18:22 GMT, in a place far, far away, Alan Baker
made the phosphor on my monitor glow in such a
way as to indicate that:

In article ,
h (Rand Simberg) wrote:

On 8 Oct 2003 10:19:49 -0700, in a place far, far away,
(Stuf4) made the phosphor on my
monitor glow in such a way as to indicate that:


- Gravity is *distinctly different* from acceleration.

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

Your continued repetition of this statement does not make it true.

No.

The fact that it's true is what makes it true.

No, gravity doesn't "have a property of acceleration." The statement
is not true.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers:

From Scott Hedrick:
On 8 Oct 2003 17:41:25 -0700, in a place far, far away,
(Stuf4) made the phosphor on my
monitor glow in such a way as to indicate that:

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

Verifiable reference, please. Not just the name of a book, please
provide
the specific page and a quote.

I just found this page that gives a good set of q/a's:

Why don't you provide a verifiable reference to the source you used *at the
time* you first posted this nonsense? Trying to Google a source after the
fact won't help you.

I didn't look up any reference when initiating criticism about
zero/microgravity. I posted what I knew by memory from concepts I
learned many years ago.

(Though I'm puzzled as to why before or after the fact makes a
difference to you.)


~ CT

From Rand:
On Wed, 8 Oct 2003 21:06:56 -0500, in a place far, far away, "Jon
Berndt" made the phosphor on my monitor glow
in such a way as to indicate that:

"Rand Simberg" wrote in message

Which doesn't mean that gravity is not acceleration. Nice diversion,
though.

Gravity is a force - the weakest of the four fundamental forces
(gravitational, electromagnetic, weak, and strong IIRC). The [gravitational]
force *causes* acceleration. Gravity is not acceleration. The value for the
acceleration *due*to*gravity* at sea level on earth is about 32.2 fps^2.

Well, if one wants to get pedantic, gravity is a quantitative
mathematical model invented by Newton to explain why apples fall from
trees and planets orbit suns.

Please note that we have been discussing gravity and acceleration as
actual physical phenomena, not just math models.

In any event, the effect of it is an acceleration, something that
Stuffy seems to want to deny, or at least obfuscate.

I've seen no disagreement to the fact that gravity causes
acceleration.

The main point of focus has been that the concept of gravity is
distinct from the concept of acceleration. While the force of gravity
causes acceleration, many accelerations are not caused by the force of
gravity.


~ CT

From Herb Schaltegger:
The statement you are quoting has been accepted physics since it was
spelled out in detail in Isaac's Principia.

You and Newton on a first name basis these days?

At his mixers, he may have preferred to be called "Sir Isaac" to impress the ladies.


~ CT