Soon after a strong earthquake rattled Acapulco, the hashtag "Apocalipsis" began trending, notes NPR. But the reference to the apocalypse and the end of days wasn't so much about damage caused by the quake as the weird lights in the sky. See for yourself in a few of the many videos in circulation here, here, and here. The lights began shortly after the ground began shaking, filling the sky with flashes of blue, white, and pink, notes Reuters. The phenomenon is generally referred to as "earthquake lights," or EQL, and a Rutgers physicist tells NPR that it's got nothing to do with the world ending. "If it did, the apocalypse would have happened a thousand years ago when this was first discovered," says Troy Shinbrot.
Researchers, however, still aren't sure what causes the lights, or even whether all the reports of them are actually linked to quakes. One leading theory is that friction between rocks near the Earth's crust results in a release of energy and, voila, light show. The official word from the US Geological Survey: "Geophysicists differ on the extent to which they think that individual reports of unusual lighting near the time and epicenter of an earthquake actually represent EQL: Some doubt that any of the reports constitute solid evidence for EQL, whereas others think that at least some reports plausibly correspond to EQL." In some cases, the lights were discovered to be caused by the shaking of power lines. In others, researchers say it was regular old lightning unrelated to a quake. (Read more earthquake stories.)