People in the Philippines were terrified at the sky turning a deep purple, some were say it was the end of the world. The witnesses said the light grew brighter as the clouds moved.
Responding to some whom said it was caused by a beam of light coming from the ground, viewers said it was definitely coming from the clouds and not a light from below.
Some went with the thought that the light was caused by a portal opening from another dimension and others believed it was coming from a giant UFO mothership.
As of now, there is no definitive reason. So let your imagination run wild.