Pulsar CP 1919, now known as PSR B1919+21, is a radio pulsar—a rapidly rotating neutron star that emits beams of electromagnetic radiation. It was discovered in 1967 by Jocelyn Bell Burnell and her PhD supervisor Antony Hewish, making it the first pulsar ever detected.
This pulsar has a rotation period of 1.3373 seconds, meaning it sends out pulses of radio waves at regular intervals. Initially, its precise and rhythmic signals led researchers to briefly consider the possibility of an extraterrestrial origin, earning it the nickname LGM-1 ("Little Green Men").
Beyond its scientific significance, CP 1919 became an iconic piece of pop culture thanks to its radio signal visualization, which was famously used as the cover art for Joy Division’s 1979 album Unknown Pleasures. The jagged, wave-like pattern of the pulsar’s emissions has since become one of the most recognizable images in music history.
