I just rejoined ASP (Astronomical Society of the Pacific; I got a job in a
dept with lots of astronomers and I'm doing my homework) and in the very
latest _Mercury_ 25(3), May/June 96 there are two relevant articles:
Ashby, Neil (1996). Relativity in the palm of your hand. Mercury 25(3), 23-
27. Nice read about relativistic effects on GPS and handheld GPS systems;
the apparant clock rate <=> earth rotation problem is discussed and
apparantly is called the Sagnac clock effect. The clock keepers apparantly
have to apply a correction to get to the Earth-centred inertial frame, and
the correction is not required to synchronize between two points on a NS line.
Thomas, Peter C. (1996). The shape of things to come. Mercury 25(3), 23-
27. Nice pictoral account of different sized planetoids and planets,
discussing how shape is affected by spin, mass and density. (Why are some
things round and not so; why are planets the shapes they are.) Also discusses
the effect on surface gravity due to these parameters. Looks like putting
a satellite into orbit about a planetoid that deviates significantly from
spherical is quite a nightmare, especially if you don't know the field to
start with and you have to account for the spacecraft to the taxpayer. The
Near Earth Asteroid Rendevous project (to Eros) is going to be quite a
challenge (and goes in with thrusters live).
A sharp journal, written at a great level for nonexperts. good article
discussing barebones intro interferometry & radio astronomy too.
Dan MacIsaac, Assistant Professor of Physics and Astronomy, Northern AZ Univ
Visiting Asst Prof, Purdue Univ; Adjunct Faculty, Indiana Univ at Kokomo
danmac@physics.purdue.edu http://physics.purdue.edu/~danmac/homepage.html