Physics Seminar
Wednesday, September 15, 2004, 4:30 pm
Willet Science Center 101


James H. Shirley

Jet Propulsion Laboratory


A Fourth Inertial Force


Inertial forces play an important role in general circulation models of terrestrial, planetary, and stellar atmospheres.   We show here that the inertial forces arising due to axial rotation in combination with orbital revolution differ from those due to rotation alone.  A new derivation yields the usual centrifugal, Coriolis, and angular acceleration forces, together with one additional term.  Like the centrifugal force, this 'fourth inertial force' varies with location; unlike that force, it varies substantially with time.   The fourth inertial force is typically about half the size of the Coriolis force for synoptic-scale atmospheric motions in terrestrial middle latitudes; it has apparently eluded direct detection and study because it has no radial component.  Many prior observations and a number of anomalous experimental results may be explained by this hypothesis.  The fourth inertial force gives rise to continuous circulatory flows of geophysical and astrophysical fluids.

Please join us for light refreshments at 4:15pm outside WSC 109.