On-Axis Tidal Forces in Kerr Spacetime

Understand

Tidal forces are an important feature of General Relativity, which are related to the curvature tensor.

• We analyze the tidal tensor in Kerr spacetime, with emphasis on the case along the symmetry axis of the Kerr black hole, noting that tidal forces may vanish at a certain point, unlike in the Schwarzschild spacetime, using Boyer-Lindquist coordinates.
• We study in detail the effects of vanishing tidal forces in a body constituted of dust infalling along the symmetry axis.
• We find the geodesic deviation equations and solve them, numerically and analytically, for motion along the symmetry axis of the Kerr geometry.