# Producing an audible sound from the gravitational waves of the GW150914 event

As is said in the latest LIGO press realease, the detected gravitational waves vary with a frequency that is audible for us. The audio one can obtain from the detected data is actually plaied during the press realese: see https://www.youtube.com/watch?v=aEPIwEJmZyE&feature=youtu.be&t=2754 at 45:54.

I tried to reproduce this same sound, starting from the public data of the event: https://losc.ligo.org/events/GW150914/

What I do is to get the raw data from https://losc.ligo.org/s/events/GW150914/P150914/fig1-waveform-H.txt. This dataset contains only $3400$ rows, so I add new data by adding linearly interpolated data.

A sample of the python script (needs python3) is here: https://gist.github.com/anonymous/2f5f7d1824c11d2698b1

Unluckily I get something ways more noisy and "flat" than the one presented in the press release.

Do someone know which technique they used? maybe they have a sample with more datapoints in time?

• She says "but it's so short it's just a thump, so ... we have shifted [the signal] a bit in frequency". So have you tried stretching the signal? – lemon Feb 12 '16 at 18:43
• @lemon, yes. I see I was not clear: the whole part of the oversampling whit linear interpolation is to stretch the signal (more points at the same rate) – Antonio Ragagnin Feb 12 '16 at 18:53
• As with most scientific "visualizations" one has to cheat to make it more interesting. I don't think that this one is of much use... the much more interesting piece of this phenomenon is the one that LIGO wasn't able to measure: it's the long, increasing rise of frequency as the two bodies are rotating ever closer. This sound is just the finale of a very long gravitational song (or scream of death, if you wish), that these two bodies are singing together. Future observatories will hear the singing of the gravitational universe. – CuriousOne Feb 12 '16 at 20:05