Killing Vector Field The Killing vector field is a vector field on a differentiable manifold that preserves the spacetime metric. In other words, it generates an isometry of the metric. Although the Killing vector that corresponds to time translation is timelike (c^2 dt^2 > dr^2) at spatial infinity, it need not be timelike everywhere outside…
Large Hadron Collider and proton energies The Large Hadron Collider has produced collisions at 7 TeV. For collisions at 7 TeV, each proton must be ramped to 3.5 TeV. The proton has a mass of 1.6726e−27 kg, which corresponds to a rest energy of 938.272 MeV (1 eV = 1.6022e−19 J). At 3.5 TeV each…
From Exploring Black Holes by John Wheeler and Edwin Taylor. The relations below apply to any object falling radially toward a static, spherically symmetric mass (assuming the mass of the infalling object is much smaller than the central mass). Types of radial infall Drip — dropped from rest at ro Rain — dropped from rest…
Introduction This Insight explains how it is possible to calculate the spin of Sagittarius A* — the supermassive black hole at the center of the Milky Way — using a small set of observations and a few equations derived from the Kerr metric. The calculation described below follows the approach in the source paper: Spin…
Time dilation near a Schwarzschild black hole The following is an overview of the time-dilation and gravitational-redshift effects of a static (Schwarzschild) black hole. By general relativity, a strong gravitational field can slow down time. The closer you get to the event horizon of a black hole (if you could survive the tidal gravity gradients…