“Science doesn’t always go forwards. It’s a bit like doing a Rubik’s cube. You sometimes have to make more of a mess with a Rubik’s cube before you can get it to go right.” -Jocelyn Bell-Burnell
Observations that surprise us, of a phenomenon we weren’t expecting and don’t have an explanation for, are some of the most exciting things we can encounter in astronomy. In 1967, regularly pulsing radio sources, discovered without any expectation, provided exactly that. It wasn’t noise; it was definitely a robust, repeatable observation; so what was it?
The data from the first pulsar ever found visualized and stacked. Image credit: Graphis Diagrams: The Graphic Visualization of Abstract Data, edited by Walter Herdeg, The Graphis Press, Zurich, 1974. Later made much more famous as a Joy Division album cover.
While our imaginations might have run to aliens initially, further developments quickly showed that this was a ball of rapidly rotating neutrons, more massive than even the Sun but only a few kilometers in diameter. These pulsars, as they’re now know, are ubiquitous and come about from the corpses of core-collapse supernova. Could this be a harbinger of what we can expect from the ‘alien megastructure’ controversy?
Artist’s conception of worlds around PSR 1257+12, the first system (discovered 1992) with verified extrasolar planets. Pulsar systems can have planets, but they themselves are not indicative of aliens. Illustration credit: NASA/JPL-Caltech/R. Hurt (SSC).