Binary black hole demo movie

leave a comment »

black holeThis movie is divided into two parts, each part showing a different numerical simulation, with brief captions that describe what is being shown. Part 1: Binary black holes orbit, lose energy because of gravitational radiation, and finally collide, forming a single black hole; gravitational waveform, spacetime curvature, and orbital trajectories are shown. Part 2: Event horizon and apparent horizons for the head-on collision of two black holes.

Part 1:
The upper movie shows in the upper half of the screen the orbits and the apparent horizons of the two holes, in the coordinate system used in the computation. The bottom half of the screen shows the spacetime geometry in the holes’ orbital plane. The depth of the surface is proportional to the scalar curvature of space. (For the two-dimensional orbital plane the full spatial curvature is determined by the scalar curvature.) The colors encode the lapse function — the slowing of the rate of flow of time. The arrows show minus the shift — which can be thought of as the velocity of flow of space. The beginning of the inspiral is shown, and then the last several orbits, the merger of the two holes, and the vibrational ringdown.

The final hole does not look pefectly spherical because the computer code that created this movie chose spatial slices with a bit of crinkliness in them at the end. This simulation lasts for 16 inspiral orbits, followed by merger and ringdown, and it achieves a cumulative phase accuracy for the emitted gravitational waves of about 0.02 radians (out of roughly 200 radians, i.e. a fractional phase error of 1 part in 10,000).

Part 2: Head-on collision of two black holes. The individual apparent horizons (blue) move together, and eventually a common apparent horizon (green) pops up discontinuously in time. The event horizon (gray) evolves continuously in time and is always outside or coincident with the apparent horizons.

The simulation and rendering were performed by members of the SXS collaboration (, using the SpEC code ( and the open-source visualization application ParaView (

For more details of the simulation in Part 1, see the paper Scheel et. al., Phys. Rev. D 79, 024003 (2009) which can be found at… (also available at

For more details of the simulation in Part 2, see the paper Cohen et. al., Class. Quantum Grav. 26 035005 (2009) which can be found at… (also available at

Written by physicsgg

August 18, 2013 at 5:42 pm


Tagged with

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: