Chronology | Current Month | Current Thread | Current Date |
[Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
John Mallinckrodt wrote:
Because I haven't heard anyone explicitly correct the misconception that
"microgravity" is just a weak "gravitational force" or that it is somehow
related to "apparent weight" allow me to do so: "Microgravity" refers to
the tidal effects which are gravity's only essential contribution to the
observable world and which are exceedingly small (hence, "micro") near the
earth. In a freely falling frame like the shuttle--which eliminates the
overwhelming and misleading appearance of a nearly uniform "gravitational
field"-- we find it much easier to observe these tidal effects.
Now I am confused. I explicitly stated that the principle of
equivalence applied *locally*. So far as I know there's no locally
observable effect of a tidal force. By "microgravity" I mean
"microgee", or gravitational fields being less than or of the order
of 10^-5 N/kg. As John correctly points out, the tidal effects are
observable in the space shuttle (see the cited article), but I don't
think they are the effects that are studied in what are usually
termed "microgravity" experiments.