With the tragedy and horror wreaked in Morocco last week, it's unsurprising that people’s focus hasn’t been on the skies. And yet, Friday’s devastating earthquake, has also sparked renewed interest in a mysterious aerial phenomenon. Footage shared to social media just moments before the 6.8-magnitude tremor struck the High Atlas mountains appears to show blinding lights flashing across the sky. Experts have suggested that the jaw-dropping sight is evidence of an enigmatic natural occurrence called “earthquake lights”. Reports of these bright flashes go back centuries. And yet, very little is known about them, to the point that scientists aren’t even sure they’re real. Indeed, some experts have concluded that there isn’t sufficient proof to support their existence, the United States Geological Survey notes. Nevertheless, “people have wondered about them forever," Karen Daniels, a physicist at North Carolina State University, told the New York Times. "It's one of those persistent mysteries that hang around and never quite get nailed." The issue with studying earthquake lights is that since earthquakes are impossible to predict, so are any preceding celestial pyrotechnics. Not knowing when or where they will occur means researchers can’t preemptively install the necessary equipment needed to detect them. Essentially, the only evidence we have comes from eyewitness accounts and, more recently, video recordings. And there is an abundance of the former, with a 2014 study noting that aerial luminous phenomena were reported in relation to 65 earthquakes which occurred in Europe and America over a period of 200 years. These descriptions of earthquake lights vary in their details, with some recalling on-and-of lightning-style flashes, and others minutes-long glows of different colours. “All of these have been reported by observers,” John Ebel, a seismologist at Boston Collegel told the NYT. “Which ones are actually true, and which ones are products of their imagination, we can’t really say.” One theory behind the formation of earthquake lights is that they are the result of friction between tectonic plates generating electricity. However, most experts are unconvinced by this hypothesis, including Dr Daniels. She told the NYT: “Rock on rock is not a situation where people have been able to generate large charge separation. And so it just doesn’t seem like a very good explanation for what people see.” Other scientists have suggested electrical arcing from power lines shaken by earthquakes could be responsible for the sky flares. But Dr Daniels acknowledged it’s still possible that there’s no link at all between the lights and tectonic events. “We’re comforted by things that we can understand, and we’re scared by things we don’t,” she pointed out. “I think that’s part of the reason we’re so fascinated by this phenomenon.” Sign up for our free Indy100 weekly newsletter Have your say in our news democracy. Click the upvote icon at the top of the page to help raise this article through the indy100 rankings.