The next time your computer or smart phone crashes, it might just be due to electrically-charged particles generated by cosmic rays, rather than the manufacturer. The rays arrive from outside the Solar System and cause operational failures in microelectronic circuitry:
"This is really a big problem, but is mostly invisible to the public," said Professor Bharat Bhuva, at the Vanderbilt University, to a meeting of the American Association for the Advancement of Science. The problem is due to a cascade effect when cosmic rays strike the atmosphere, creating secondary particles, including energetic neutrons, muons, pions and alpha particles. Millions of these particles strike us every second, apparently, without any ill effects.
A fraction of the particles have enough energy to interfere with electronic equipment. When they strike an integrated circuit they might alter bits of data stored in memory. This occured in 2008 when a Quantus jet's autopilot disengaged due to a SEU , or single event upset, causing the aircraft to plummet 690 feet in 23 seconds, injuring a third of passengers. SEUs have caused the cancellation of hundreds of flights. An electronic voting machine was affected by an SEU in Belgium, adding thousands of extra votes to one candidate's total.
"When you have a single bit flip," said Professor Bhuva," it could have any number of causes. It could be a software bug or a hardware flaw, for example. The only way you can determine that it is a single-event upset is by eliminating all other possible causes. The semiconductor manufacturers are very concerned about this problem, because it is getting more serious as the size of transistors in computer chips shrink and the power and capacity of our digital systems increases.
"In addition, microelectronic circuits are everywhere and our society is becoming increasingly dependent on them," he added.