A pulsar is a highly magnetised neutron star, with a radius of 10-15 km, having somewhat greater mass than the Sun which has a radius of approximately 1 million km. Radiation is beamed out along the magnetic poles and pulses of radiation are received as the beam crosses the Earth, in the same manner as the beam from a lighthouse causes flashes. Being enormous cosmic flywheels with a tick attached, they make some of the best clocks known to mankind.
The sounds on this web page directly correspond to the radio-waves emitted by the
brightest pulsars in the sky as received by some of the largest radio
telescopes in the world. To listen to the pulses of a radio pulsar,
click on the sound icons below. Click on the movie icons to see visualisations of the signals.
When you listen to the sounds of pulsars, imagine these objects which are half a million Earth masses whizzing around!
See here for a list of useful other resources of information.
Some answers to common questions can be found below. Other pulsar sounds can be found on the webpage of the Dutch pulsar group.
Pulsar name |
Audio recording |
Movie pulse train |
Movie pulse stack |
Rotation period |
Age |
Comments |
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0.714520 sec (or 1.40 Hz) |
~5.5 million year old |
This is the brightest radio pulsar in the northern sky. Otherwise this pulsar is a typical, normal pulsar, rotating with a period of
0.714520 seconds, hence the star makes about one and a half turn in a second, giving it a locomotive kind of sound.
You can hear and see that each pulse has a different structure, hence the beam of this cosmic lighthouse is constantly changing in shape. This recording has been made with the Lovell telescope in Jodrell Bank. |
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0.769006 sec (or 1.30 Hz) |
~200,000 years old |
Notice that halfway through the recording much more of the pulses have become single-peaked rather than double-peaked. This is because of a so-called "mode-change". For this pulsar the properties of the lighthouse beam can be in two distinctly different states. This recording has been made with the Lovell telescope in Jodrell Bank. |
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0.358738 sec (or 2.79 Hz) |
~900,000 years old |
This is the live data of pulsar B1933+16 used in "Sky At Night" which was broadcast on BBC 4 on March the 9th 2014 at 22:00. During the recording the telescope moves towards the pulsar and after six seconds the heartbeat-like pulsar signal is being received. This recording has been made with the Lovell telescope in Jodrell Bank. |
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0.197108 sec (or 5.07 Hz) |
~500,000 years old |
This is an example of a more complex pulsar signal. This pulsar is oriented such that we can observe both opposite magnetic poles, resulting in a main and interpulse for each rotation. The pulsar rotates every 0.197 seconds, but every 0.1 seconds a pulse is observed. To complicate things further, the interpulses get weaker and stronger every 20 rotations or so, creating a nice beat as you can hear.
This recording has been made with the Parkes radio telescope in Australia. |
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Not available |
0.089328 sec (or 11.2 Hz) |
~10,000 years old |
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 (a so-called neutron star) is the collapsed core of this star, rotating with a
period of 89 milliseconds or about 11 times a second. This recording has been made with the Parkes radio telescope in Australia.
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Not available |
0.033045 sec (or 30.3 Hz) |
Born in 1054 A.D. |
This is the youngest known pulsar and lies at the centre of the Crab
Nebula, the supernova remnant of its birth explosion, which was
witnessed by Europeans and Chinese in the year 1054 A.D. as a day-time
light in the sky. The pulsar rotates about 30 times a second, however for most rotations no radio waves are detected. But every now and then a pulse is detectable which can be extremely strong and therefore called "giant pulses". Among weaker ones, the strongest giant pulse in this recording occurs close to the end. This recording has been made with the Lovell telescope in Jodrell Bank. |
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Not available |
0.005757 sec (or 173.7 Hz) |
Very old |
This is the brightest so-called milli-second pulsar known. This old pulsar
has been spun up by the accretion of material from a binary companion
star as it expands in its red giant phase. The accretion process
results in orbital angular momentum of the companion star being
converted to rotational angular momentum of the neutron star, which is
now rotating about 174 times a second. It spins so fast that the signal sounds like an overactive bumble-bee.
This recording has been made with the Parkes radio telescope in Australia. |