The way we might protect ourselves from an exploding star could help us find alien civilisations

Eventually, stars die — not with a whimper, but with a bang.

When they do, there’s the potential that any nearby planets could be devastated by destructive cosmic rays, potentially wiping out life on those worlds.

We’re not quite ready to build any sort of defence for human civilisation against a barrage of this sort, according to Milan Cirkovic and Branislav Vukotic of the Astronomical Observatory of Belgrade, writing in a study published this month in the journal Acta Astronautica.

But they theorise that in a time span ranging from a few decades to a hundred years away, we might be able to construct the sort of barrier that could withstand a blast of electromagnetic or cosmic-ray radiation that would be caused by a supernova or gamma ray burst from the end of other sorts of star (though predicting these explosions and their trajectories may be more complex than building that barrier).

And if we aren’t alone out here in the universe, other “emerging” civilisations may have built similar protective shields. With that in mind, we have another idea of what to look for out there in our search for alien life. Statistically, it makes sense that life has developed on other planets around other stars — it should be the case, even if we’ve never spotted it. Now there’s something else we can look for, something we might associate with a civilisation not too far technologically beyond our own.

It’s not too surprising that we haven’t yet spent much time thinking about how to prepare for a cosmic blast, according to Cirkovic and Vukotic. But in recent decades, scientists have started to consider and weigh the impact of various sorts of “existential disasters” — ranging from a supervolcanic eruption to the sort of asteroid strike that helped wipe out the dinosaurs to a cosmic blast.