# #Mon Aug 09 12:06:31 CEST 2010 Text__xTEnEKOdEd-WfYQ0GneCwQ_title=Tops are tilting in the gravitational field of the Earth Text__xTEnEKOdEd-WfYQ0GneCwQ_text=

According to classical newtonian mechanics the rotation axis of a spinning top - physicists call them gyroscopes - always shows in one an the same direction as long as there are no external forces.

However, in Einsteins General Relativity with curved space-time changes in the direction may arise, as compared with a fixed reference point. On the one hand side these are due to the curvature effect near a mass (de Sitter precession), and on the other hand due to a dragging effect caused by the rotation of the mass (Lense-Thirring effect).

In analogy to electrodynamics one subsumes these effects to gravitomagnetism.