Social media lit up last week with video clips taken by shocked bystanders in Korea and Japan, who noticed an incredibly bright, cone shaped light illuminating the sky on December 30th. Even among the glare of city lights in Seoul, this extraordinary sight was visible. Was it a UFO—or worse, an unexpected visitor from the north?
Deep breath, everyone. It was notations, or a missile. Rather, it was the next phase in Korea’s expanding space program.
The zig-zagging contrails followed by the brilliant cone or triangle of white light against the sky signaled the successful second test of the country’s new solid fuel rocket, developed to put spy satellites in space and to bolster the nation’s defense.
Hundreds of calls were made by concerned citizens to authorities across South Korea, fearful that what they were seeing might be the start of a war or an alien invasion. The government said they could not alert the public to the launch beforehand for security reasons.
The cone of light was most likely caused by an effect known as the “twilight phenomenon”, in which exhaust particles from a launch’s vapor trail condense, frees, and then expand in the upper atmosphere as it becomes less dense. The resulting exhaust plume reflects light and creates a massive, colorful display for anyone watching from the ground. Occasionally, it appears like a giant “sky jellyfish.” This time it was more like a cone.