Big “wobbles” in Earth’s magnetic field more than 40,000 years ago could have made the cultures of the time feel wobbly as well. Early modern humans might have adapted to the wobbly field better than Neanderthals.

Earth’s magnetic field protects the surface from high levels of solar radiation. But during a period known as the Laschamp Excursion, which began 42,000 years ago, the field weakened to just 10 percent of its current intensity. And instead of acting like a bar magnet, with strong north and south poles, it generated smaller poles all across the planet.

As the field wobbled, it produced brilliant auroras in regions where they had seldom been seen. It also allowed more radiation to zap the upper atmosphere. That destroyed some of Earth’s protective ozone. It also changed climate patterns across the planet. This turbulent period lasted about 1800 years.

A new study found changes in the behavior of Neanderthals and modern humans in Europe and Asia during this period. The changes suggest these cultures were trying to protect themselves from the dangers of the weakened field, including sunburn, higher rates of skin cancer, and eye damage. The early humans apparently adjusted better than Neanderthals.

Many factors were involved in the behavioral changes. Even so, researchers say the Lashcamp Excursion might have spurred early humans to respond to their changing environment.

Script by Damond Benningfield