Mysterious light in sky above Southern California, Arizona explained

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LOS ANGELES -- There's now an explanation for a strange light seen in the sky over Southern California and Arizona.

Many people posted similar videos on social media Saturday night, using the hashtags "UFO" and "comet."

But, the Pentagon says it was neither of those. The light came from a missile test launch, fired by the Navy from a submarine off the coast of Southern California.

The missile was not armed.

The test was routine, but classified ... which is why the Pentagon didn't issue a warning prior to its launch.

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