Cosmic election

The universe is full of cosmic rays, blasted out from neighbouring galaxies, supernovae, and the like. In 2003, they nearly changed the outcome of a local Belgian election.

Computer microprocessors and computer memory operate in 1s and 0s: bits. We all know this. These bits, physically, are sometimes recorded and transmitted as an electrical charge – a relatively high charge represents a 1, a lower charge represents a 0. (Side note: this is not the only way that bits can be transmitted or recorded. But this post isn’t about bits, it’s about elections.)

Cosmic rays hit our planet all the time. When these rays strike the atmosphere they generate “air showers,” clusters of secondary particles created by the cosmic ray interacting with the atmosphere. These ionised particles have a charge, and if one of them should hit just the right place on a computer they can cause a bit to flip from a 0 to a 1. When it happens, this is known as a single event upset.

Usually, a one-bit change isn’t enough to cause major repercussions. But in 2003, in a local election in Schaerbeek, Brussels, one candidate got 4,096 extra votes. Anyone with a background in computers will immediately notice that number, because it’s a power of two (2¹², to be precise). It’s a clear clue that somewhere, somehow, a bit has been flipped.

And that’s precisely what they thought happened here. A cosmic ray, or one of its secondary particles, hits a bit in the vote tallying computer, and *poof* 4,096 extra votes appear out of nowhere. They caught and corrected the error this time; I hope we’re always that lucky.

Oh, single event upsets can also fry airplane circuits mid-flight. Best not think about that too much.

• Single event upset
• Cosmic ray
• Air shower