But it’s a big galaxy, and knowing where to look for signals that might mean we’re not alone is a tough task. Devoting limited and expensive resources to randomly listen to chunks of the sky in the hopes of hearing something that’s obviously made by a technical civilization is unlikely to bear fruit. Much better would be to have something to base sensible observations on — some kind of target that has a better chance of paying off.
Luckily, a chance observation nearly 50 years ago has provided just that. The so-called Wow! Signal, much discussed but only occasionally and somewhat informally studied, has provided a guidepost in the sky, thanks in part to a citizen scientist with a passion for finding exoplanets.