A university’s prediction that the Northern Lights would be widely visible turned out to be a mistake caused by a lawnmower.
The Aurora Watch service, based at Lancaster University in the UK, forecasts likely sightings of the Aurora Borealis, a natural colored light show caused by solar winds disturbing the Earth’s magnetosphere.
Forecasting is of particular interest in the United Kingdom because it’s at a latitude visibility across the country will vary dramatically depending on the level of geomagnetic activity. AuroraWatch uses several magnetometers around the country and in the distant Faroe Islands, then issues alerts based on the readings. These go out on social media, email and through dedicated apps.
Earlier this week the project issued a rare red alert, which means that “It is likely that aurora will be visible by eye and camera from anywhere in the UK.” It seems several recipients began making plans to find a suitable viewing location after dark and away from light pollution and cloud cover.
Later that day staff made an embarrassing withdrawal of the alert. It turned out it had been issued based on only one magnetometer that was being used as a backup. Unfortunately that turned out to have been hit by a local spike, initially thought to be from something metallic involved in other experiments at the site.
Later it emerged the cause was even less sophisticated: “We believe the interference was caused by University staff mowing the grass on a sit-on mower.”