Shortly after sunset on June 18, 2013, a woman drove her minivan onto Brighton Street in Belmont, Massachusetts. Her GPS told her to turn right. But the metallic voice, guided by satellite data, steered her wrong: onto a railroad track. She tried to drive off, but the van got stuck. No sooner had she unbuckled herself and her two kids and ushered them out than a train crumpled her car into a ball of foil. Not long after, someone sent a news story about the incident to space physicist Tamitha Skov. She didn’t just see a GPS acting up. She saw the sun acting up. While our star looks calm and contained, its surface roils: Spots form and darken it like scabs; loops of plasma link its regions; its atmosphere streams farther outward than the star is wide. Solar flares, which are bursts of radiation, and coronal mass ejections, which are bombs of stellar material, disturb both Earth’s magnetic field and upper atmosphere. There, they disrupt devices—like GPS receivers—that rely on electricity or radio communication. This interplay between the sun and Earth is called space weather, and it is Skov’s specialty.
At the time, Skov had just begun a Web video series that gave space-weather forecasts, much like the predictions Al Roker makes on TV for clouds and sunshine. In it, she explained how our nearest star affects Earth. She had a modest but engaged following. Motorists were already starting to tip her off whenever their SiriusXM service cut out, airline and small-craft pilots would tell her when navigation went awry, and taxi drivers would describe routing errors.
A number of these accounts involved drivers rolling, at the behest of their GPS, onto train tracks, or other not-roads, especially near dawn and dusk. At first, Skov blew off these anecdotes.
When the reports kept coming, she consulted an atmospheric expert at the Aerospace Corporation, a federally funded R&D center where Skov works as a research scientist. “What’s up with this?” Skov asked her colleague. “Is it something?” Yes, the woman replied, the atmosphere is always unstable at sunset and sunrise. Add solar flares to that? “It could definitely make a difference,” the expert said. Skov checked the website of the Lockheed Martin Solar and Astrophysics Laboratory to see if there had, in fact, been a solar flare around the time of the woman’s fateful drive. And there it was: a C-class outburst, medium strength.