In July 1967, Jocelyn Bell Burnell and Anthony Hewish of the SETI (Search for Extra-Terrestrial Intelligence) project came across some strangely regular radio signals and dubbed it LGM-1 (for Little Green Men, who they figured might be sending the signals). Later work showed it to be something even stranger than alien DJs sending out their tunes into the universe: a pulsar.
Pulsars – short for pulsating stars – are rotating neutron stars (extremely heavy, hot stars composed almost entirely of neutrons) that emit radio waves, X-rays and gamma waves, all high-energy stuff. They pulse in periods of 1.4 milliseconds to 8.5 seconds – hundreds of thousands of times faster than the Earth spins – and are so regular you could set your watch by them. Their radiation can only be observed when the beam is pointing towards Earth (sort of like a lighthouse beam).
Oh, and Prof. Hewlish became the first astronomer to win the Nobel Prize for physics (in 1974). Bell, who was his PhD student and made the initial discovery, didn’t share the prize. That’s just not on, but sexism in science wasn’t exactly rare in those days, sadly.
