For centuries, people have reported seeing a wide variety of illuminations just before and during major earthquakes. What gives? Some kind of divine force above shining down on us? The origins of it have consistently baffled scientists. At least, up until now.

A new study seems to have found an explanation. According to the research led by Robert Thériault, a geologist at Quebec's Ministry of Natural Resources in Quebec City, Canada, he and his team went as far back as the 1600s to found at least 63 of these events took place on vertical geological faults.

Because of this, the orientation allows for electric charges sparked by grinding rocks to travel upward to the earth's surface. When they hit the atmosphere, they become really pretty - colorful and scary.

From Nature:
It all starts with defects in a rock, where oxygen atoms inside a mineral's chemical structure are missing an electron. When the stress of an earthquake hits the rock, it breaks chemical bonds involved in these defects, creating holes of positive electrical charge. These 'p holes' flow can vertically through the fault to the surface, triggering strong local electric fields that can generate light.
A YouTube search for the phenomenon will yield a handful of examples everywhere from Christchurch, New Zealand to Sichuan, China.

So can we rule out aliens for this one? [Nature Lead image is a composite via Library of Congress & NASA]