7 Times We Really Thought We'd Found Aliens

4. The Puzzling Pulsars

As a postgraduate student working with radio telescopes, Jocelyn Bell Burnell was devoted to the study of quasars.

Quasars are hugely energetic objects (as in, they give off a lot of energy, rather than running around knocking over ornaments), that are thought to be formed when black holes or even whole galaxies collide.

Bell noticed some very odd readings coming through in her research. In certain regions of space, something was emitting a pulse of energy with alarmingly precise regularity. Bell labelled these as LGM-1, short for "Little Green Men" as these pulses were so regular that they seemed mechanical. Where these signals from a hyper-intelligent alien race? Unfortunately (or fortunately, depending on the aliens), the signals had a more natural origin.

It was eventually theorised that these signals were actually jets of electromagnetic radiation being fired out from an incredibly dense, incredibly fast-rotating neutron star. Each "pulse" represented the moment the jet swept across the Earth, like a lighthouse. They were called "Pulsars", short for "pulsating stars".