(Skye Weather) When NASA revealed its stunning new images of the Earth at night – or the Black Marble, as some referred to the darkened planet – one NPR correspondent noticed something unusual: a mysterious mass of lights in North Dakota near the Canadian border. The sighting was surprising for a few reasons. First, there are no large cities in the region that would cause the phenomenon, and second, the lights didn’t exist in that same spot six years ago. So how to explain them?

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