Re: [Phys-l] definitions ... purely operational, or not

[John Mallinckrodt <ajm@csupomona.edu>]

On Nov 10, 2010, at 10:31 AM, LaMontagne, Bob wrote:

> Actually, microgravity is a legit term. It does no mean that the gravitational feild is near zero. It only means that while in free fall, there are tiny gravitational attractions between objects that become observable.

I don't think that's what the term "microgravity" generally refers to, although I confess to being at somewhat of a loss as to what it does refer to despite having read many articles claiming to explain it.  As near as I can tell it is most often intended to refer to the residual tidal effects in an extended, freely-falling environment. 

Quick calculations: 

Tidal acceleration of two 1 kg objects separated by 1 vertical meter in the space shuttle ~ 2.5 micrometers/s^2

Self gravitational acceleration of same = 0.1 nanometer/s^2

John Mallinckrodt
Cal Poly Pomona