Frame-Dragging (Lense-Thirring Effect)

The Lense-Thirring effect is a subtle consequence of the Einstein Field Equations when applied to a rotating mass. While a non-rotating mass curves spacetime statically (described by the Schwarzschild metric), a rotating mass introduces a ‘twist’ to spacetime. This is analogous to a spinning ball in a viscous fluid like honey; the fluid near the ball is dragged by its rotation. In frame-dragging, spacetime itself is dragged. The effect is extremely weak. For Earth, the predicted precession of a gyroscope in a polar orbit is only about 42 milliarcseconds per year.

The most definitive confirmation came from the Gravity Probe B (GP-B) satellite mission, launched in 2004. GP-B used four ultra-precise gyroscopes in a polar orbit. After years of data analysis, the science team announced in 2011 that they had measured the frame-dragging effect to within 19% of the value predicted by general relativity. The effect is much more pronounced near rapidly rotating, extremely massive objects like black holes and neutron stars. Frame-dragging plays a crucial role in the astrophysics of these objects, influencing the behavior of accretion disks and potentially providing a mechanism for launching powerful relativistic jets from the poles of active galactic nuclei.