Recently, I came across an interesting factoid—the festival for the Roman God Neptune (a.k.a. Neptunalia) was held during the height of summer on July 23rd because this was the hottest part of the year, prone to drought when water is most needed. Being the god of water, Neptune would have been the one to provide this precious resource.
The reason this information caught my attention is two-fold. First, the weather has been exceptionally hot and dry in my area this summer, recently sparking wildfires around the region which make the air even more hazy and dry. This came after a record-setting winter full of moisture that then left us reeling from springtime floods. The extremes in both excess and deprivation of water are keenly felt. Second, the solar eclipse is set to hit our area soon—on August 21st—and thinking of solar objects, I can’t help but associate Neptune’s name with the planet Neptune.
Because Neptune is considered to be an “ice giant” (along with Uranus), it seems like a no-brainer that the planet Neptune would be named after the Roman god of the sea, especially because of the tradition of naming planets after Roman gods and goddesses. (And in case you’re wondering exactly what an ice giant is—it is a giant-sized planet made up mostly of heavy elements, like oxygen, carbon, nitrogen, and sulfur … which help to form the volatile chemical compounds—i.e. water—found on ice giants.) But back to the planet’s name: Neptune. Both the discovery and naming of Neptune went through a bit of debate, though.
It turns out that Galileo actually plotted the position of Neptune at the end of 1612, but he mistook it for a fixed star, so he is not credited with Neptune’s discovery. Then, in 1821, Alexis Bouvard theorized something was pulling on Uranus’ orbit. In 1845-46, John Couch Adams came up with several estimations of an undiscovered planet. Working at the same time—but separately from Adams—Urbain Le Verrier worked out his own calculations.
Seeing how similar both Adams’ and Le Verrier’s predictions were in 1846, the astronomer Sir George Airy, decided to have Cambridge Observatory Director James Challis begin actively looking for this undiscovered planet. However, Urbain Le Verrier asked another astronomer—Johann Gottfried Galle—to look for the planet using the Berlin Observatory’s refracting telescope, and on September 23, 1846, he found the planet Neptune. But because both Adams’ and Le Verrier’s predictions were so similar, heated debate between the British and French began over who should be hailed as the planet’s discoverer. At first, history came down on the side of Le Verrier, but now seems to be giving them equal credit; Neptune’s name is similarly controversial.
Galle suggested the name Janus; Challis wanted the name Oceanus, while Le Verrier himself immediately suggested Neptune only to soon recant in favor of naming the planet after himself. Of course outside of France, no one wanted to name the planet Le Verrier. So when the honored astronomer Friedrich Georg Wilhelm von Struve argued to the Saint Petersburg Academy of Sciences in December 1846 that the planet’s name should be Neptune, the international community agreed and began accepting that name. Or did they?
Although most countries use some form of the name “Neptune” for the planet, there are exceptions. In China, Japan, and Korea, the planet’s name translates to “Sea King Star” (owing to the fact that the Roman God Neptune is the King of the Sea). In Mongolia, they substitute the name of their own God of the Sea—Dalain Van—in place of Neptune. Likewise, Greeks call the planet Poseidon rather than Neptune, and the Māori call the planet Tangaroa after their version of the god of the sea. Rather than using a god of the sea, the Nahuati (or Aztec people of Central Mexico) call the planet Tlāloccītlalli after their rain god. And in 2009, Hebrews voted to call the planet Rahab after a Biblical sea monster in the Book of Psalms … so, yeah, there’s some deviation around the world on what to call the planet I know of as Neptune.
It’s not possible to see Neptune without a telescope, but the next time you do have access to a telescope (and it’s actually possible to view Neptune in the night sky), take a look and see what you think!