Is there anythign in it? IF so, why does it work? Can it be viewed as just an extension of the idea of environmental influences on character formation? Does magnetism, gravity or cosmic radiation differ when the planets are in different positions?

The outline of my star sign (sagittarian) does reflect my personality.
As do other peoples personalities.

there is quite a bit of history that astrology does have some importance in the spiritual world.

perhaps the combined gravitational effects are significant ??
Some poeple invest using a ephemeris chart (book to give star timing etc), amongst other thngs.