Ultra-violet light is not in the part of the visible spectrum, but why does an ultra-violet lamp emit violet colored light?

Its event horizon--theboundary at which nothing, not even light, can escape the monster’s gravitationalpull--is four times as large as the orbit of Neptune,our sun’s outermost planetary satellite.

We can think about the Lyman series, which is 1 where n equals 1. We know that that's going to be a higher energy difference, so that means that we're going to be in the UV range.