A Planet Called Vulcan.

According to some sources, in the 18th Century, astronomers hypothesized that there was a planet located between the Sun and Mercury, some calling it Vulcan.

Eventually, the scientific community came to the realization that Vulcan never existed.

But, well, what if it did?

From Night Zero:

Gustav Holst’s The Planets' nine movement suite started playing as I laid in bed, reading the dataflexi; I’d arranged each movement to follow each planet’s orbital path around Sol: “Vulcan, Bringer of Fire,” “Mercury, the Winged Messenger,” “Venus, the Bringer of Peace,” “Mars, the Bringer of War,” “Jupiter, the Bringer of Jollity,” “Saturn, the Bringer of Old Age,” “Uranus, the Magician,” “Neptune, the Mystic” and “Pluto, the Bringer of Wealth.” Holst had lived long enough to see Pluto discovered and eventually added the new movement; however, Eris wasn’t known until its discovery in 1981. Mars was my favorite; the Pluto movement, with its eerily haunting choral arrangement, was also outstanding and ranked second among my favorites.

Of course, nothing was ever composed for Tellus, Earth’s co-orbital twin.