﻿ GW waves

# black hole collision generating GW waves

https://www.black-holes.org/gw150914  seems to be best single site with the best collection of some short videos
[suggestive black hole collision animation: g-lens image; warped spacetime animation; undulating grid animation, etc]
[explore this website by going to the Home button and entering!]

https://gravitational_waves.ihes.fr/
French group of effective one body (EOB) approach (like reduced mass in binary problem: reduced spacetime) couple with post-Newtonian perturbation expansion (some friends of bob are pictured here); there is a complicated interaction between analytical approximation techniques, numerical relativity, and general theory.

GW wave polarization: shear effect on nearby points [MTW]
When a GW wave passes, the effects on a ring of nearby particles follow these patterns for linear and circular polarizations.

Kip Thorne 1 hour lecture  [interesting for nonexperts if you don't worry so much about details]
lecture given 1 year ago: colliding black holes, G-electric and G-magnetic field lines generating GW waves 18 in, 26 min

The GR gravitational field potentials are the coefficients of the spacetime metric, and the curvature fields analogous to the tidal Newtonian field which is the gradient of the Newtonian gravitational force field also come in electric and magnetic parts like the electromagnetic field, but here they are instead symmetric tracefree 3x3  matrix fields. These have 3 real eigenvector directions, so one can visualize these by their field lines, which are mutually orthogonal (any symmetric matrix has orthogonal eigenvectors!), so there are 3 sets of mutually orthogonal electric like (tidal) field lines, and 3 sets of magnetic like (frame dragging) field lines that help us visualize the gravitational field in GR. Thorne explains all this with nice slides. Thorne is the consultant behind the visuals of the black hole in the recent movie Interstellar [google].

I am happy to chat with anyone who has questions about GR, though I cannot promise to be very good with concrete numbers (I am more of a mathematician than a physicist!). Just send me an email!
--- bob
my webpage

less interesting stuff