Expo/Science & Industry/Spacetime Wrinkles

| Back |

Black Hole Waveforms

Distorted Black Hole

This figure shows the actual waveform calculated from supercomputer simulations. After the initial growth in the strength of the wave, there is a decaying signal of a definite frequency and damping time. This is the "ringing mode", or normal mode of the black hole. The ringing mode frequencies are known from perturbation calculations of black holes, and depend on the mass and spin of a black hole. The calculations show that the ringing mode of black hole would be excited when distorted. The resulting signal, when detected by LIGO, would allow astronomers the mass of the disturned black hole.

Rotating Black Hole

A similar calculation was performed for a distorted, rotating black hole. The waveform is very similar to the non-rotating case, but the frequencies are slightly different. In this case, an accurate detection would allow astronomers to determine not only the mass, but also the spin of the black hole.

Colliding Black Holes

This is the result of a calculation of two equal mass black holes colliding head-on. Very little radiation is emitted until the two black holes collide, forming a distorted larger black hole that then "rings" down to a quiet, spherical hole. Again, the signal would allow astronomers to determine the mass and spin of the final hole created in this process.

Notice the very strong similarity between the three waveforms presented. Taken together, these three waveforms show that a characteristic signal is expected from almost any black hole process. In particular, astronomers and physicists hope to detect the waveforms associated with all stages of a black hole collision: from when the holes spiral into each other to their merger moments later.

Return to LIGO
Exhibit Map

Copyright, 1995: Board of Trustees, University of Illinois

NCSA. Last modified 11/7/95