Swimming versus swinging effects in spacetime

Abstract

Wisdom has recently unveiled a new relativistic effect, called aœspacetime swimminga, where quasirigid free bodies in curved spacetimes can aœspeed upa, aœslow downa or aœdeviatea their falls by performing local cyclic shape deformations. We show here that for fast enough cycles this effect dominates over a nonrelativistic related one, named here aœspace swinginga, where the fall is altered through nonlocal cyclic deformations in Newtonian gravitational fields. We expect, therefore, to clarify the distinction between both effects leaving no room to controversy. Moreover, the leading contribution to the swimming effect predicted by Wisdom is enriched with a higher order term and the whole result is generalized to be applicable in cases where the tripod is in large redshift regions. © 2006 The American Physical Society.