dipper@utastro.UUCP (Debbie Byrd) (10/10/84)
Today is the anniversary of the discovery of a large moon for the planet Neptune. More on Triton -- right after this. October 10 The Amazing Moons of Neptune A man with a homemade telescope made the first discovery of a moon for the planet Neptune. William Lassell glimpsed this remote object with a 24-inch reflector on today's date in the year 1846. Today we call this satellite Triton, for the mythological son of Neptune. We know it as a faraway pinpoint of light -- which close-up appears larger than Earth's moon. This innermost moon of the planet Neptune is one of the most baffling objects in our solar system. It moves around Neptune backwards with respect to any other of the solar system's large moons -- towards the west, instead of towards the east. What's more, its orbit around Neptune is highly inclined -- and yet the shape of its orbit is pretty ordinary -- and so is its distance from its parent planet. There's at least one other moon in the Neptune system -- Nereid -- named for a bevy of sea nymphs. This small satellite moves in a forward direction, but its orbit is extremely eccentric. It sometimes comes as near Neptune as nearly a million miles -- and it gets as far away as about six million miles. One large inner moon moving backwards -- one small outer moon moving in a very eccentric orbit. The satellite system of Neptune is strange -- and you might wonder how it got that way. It's possible that some long-ago disturbance in the Neptune system left the moons in their current peculiar orbits. But at the moment, the nature of that disturbance remains unknown. Script by Deborah Byrd. (c) Copyright 1983, 1984 McDonald Observatory, University of Texas at Austin