In article ,
(Stuf4) wrote:

************************************************** ****************

Scientist: "I just measured this box with my ruler. It has one
human-foot."

CT: "You mean to say that the box is one foot long, right?"

Scientist: "I mean to say that it has one human-foot."

CT: "How can it have a human foot if it is just a box? I'm certain
that what you mean to say is that your box has the same length as one
human foot, with length being a common quality to both the box and the
foot. But a "human-foot" as a bodily appendage is distinctly
different from a "foot" as a measure of length."

Scientist: "You are just being pedantic. The terminology you are
using may apply to the field of biology, but it does not apply to my
specialty field of measuring boxes."

CT: "Um, no. I see a distinct conceptual difference between a human
foot and the length of the side of a box."

Scientist: "Now you're just playing with semantics!"


~

I hope this analogy helps to illuminate the fundamental problem with
the widely used terminology: zero/microgravity.

- 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).

Likewise...

- A human foot is *distinctly different* from length.

A foot may have the property of length, but it is *not* length.

To confuse acceleration measured in 'g' with gravity is the same type
of error as confusing a length measured in 'feet' with those
appendages at the end of your legs.

*

As there are alternative standards for measuring length that have no
basis at all in the human foot (take the meter, for example) a
standard unit of acceleration could be defined on a scale that has
nothing to do with gravity.

Let's say that this time next year, the SI unit for acceleration gets
defined as 10 meters/second^2. This unit standard gets named in honor
of the man who helped popularize acceleration entertainment for
countless families across the planet. The SI standard unit of accel
will be known as the Disney, abbreviated as "D". The unit of 1-D is
based upon a certain ride in Florida that spins you around with 10
m/s^2 of lateral acceleration, nothing at all to do with gravity.

Those wishing to conform with this SI standard can use the following
conversion factor (rounded):

1 D = 1.019 g

Notice that if NASA were to adopt this hypothetical standard, "Zero-g"
research would then be called "Zero-D" research. And when people
thought of Disney's spinning ride in Florida, they would be crystal
clear that measures of acceleration need not be based upon gravity.
No need for confusion.

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 hope this helps to clear up the mess that was created by the terms
"zero/microgravity". And if those words ever get stitched to another
NASA mission patch, I hope it includes Mickey Mouse's face to remind
us all of the silliness behind the misusage of those terms.


~ CT

--
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."