This weird sound is not created by little green men or by any techno DJs.
No, this strange noise is produced by a rotating neutron star lost in a supernova remnant.
In 1967, Jocelyn Burnell discovered a source of pulsed emissions of radio waves which she described as sounding like an “idling truck” on the radio telescope, as it had a frequency of just over 1 Hz, about the same as a large idling diesel engine.
A few theories were proposed as to the source of these emissions, including that they were coming from extra-terrestrials, because the pulses were so regular (they are more reliable than atomic clocks), leading to the first pulsar being called LGM-1 (standing for Little Green Men).
However in 1968 they were shown to be coming from rotating neutron stars, which only emit radiation along one axis, so we only see the radiation when it points our way.
Above is a recording of the Vela Pulsar sound. This pulsar lies near the centre of the Vela supernova remnant, which is the debris of the explosion of a massive star about 10,000 years ago.
The pulsar is the collapsed core of this star, rotating with a period of 89 milliseconds or about 11 times a second.
The current fastest known pulsar spins once every 1.3ms, so fast that at the equator of the star travels at 24% the speed of light.