Reproduced with permission from the neOnbubble Know You Some Science series of student learning guides.
What is Neptune?
Neptune is the outermost planet in our solar system. Pluto used to sometimes be the outermost planet (its orbit and that of Neptune crossed over occasionally) but it was relegated from the list of planets after going into administration during the recession of the early 21st century.
Neptune is a gas giant world named after the Roman god of the sea and the first planet to be detected using mathematics rather than eyeballs. Its presence was later confirmed by eyeballs because nobody trusts mathematics. Oh, mathematics says it’s your friend and it will turn up but then it lets you down.
What is a moon?
A moon – or satellite – is a body that has been captured gravitationally by a planetary body. Moons typically orbit planets trying to gather enough speed to escape the pull of the planet to which they’re bound because only by being set free can they possibly hope to be re-classified as a rogue or dwarf planet of their own and that’s where the big money sponsorship deals are made.
What are Neptune’s moons?
Neptune has thirteen known moons but most of them are small and boring. Here are some of the more interesting ones:
Triton is the largest of Neptune’s moons and is named for the god of the sea’s most-treasured possession, the trident. The person who did the naming had a cold, though, and was misheard on the phone.
Triton orbits Neptune in the opposite direction to all the other satellites. Some people believe that this is because Triton is an artificial construct put in place to determine whether we have advanced as a species far enough to question the absurdity of its presence. But these people are nutcases. More likely, Triton is simply a non-conformist rebelling against the man.
Triton’s surface is mostly chalk. It couldn’t be more different from our moon, although that’s not because our moon is made of cheese; it’s simply that our moon’s surface isn’t mostly chalk.
Photographed by Voyager 2 in 1989 as it passed Neptune and its moons, this picture shows Proteus, the largest of Neptune’s satellites after Triton. Proteus has an irregular shape as it is still growing but in time it will become a beautiful, spherical moon just like all the other great moons in the solar system.
The black dots on the image do not actually exist on the surface of Proteus. In 1989 Voyager 2 had attained level 2 of sentience and was attempting to encourage its creators back on Earth to play dots and boxes with it. NASA scientists do not play dots and boxes.
Thalassa is the second innermost of Neptune’s moons and irregularly-shaped (as shown in the simulated image above). It is composed of the re-accreted rubble of other moons that have been torn apart by Triton as it shows no respect for its siblings in its headlong rampage around Neptune in a retrograde orbit.
Thalassa’s orbit is unstable and it will eventually plummet into Neptune’s atmosphere. This has given Thalassa a rather bleak outlook on life but it has channelled some of those feelings into writing dark poetry that some critics have rated very highly. Not me, though. I think it’s emo rubbish.
Daphne is the moon of Neptune nobody else talks about. Named by its discoverer Nigel Hamstring in 1983 allegedly for the naiad in Greek mythology it later transpired that the amateur astronomer has also tried and failed to name a comet for Scrappy Doo, an asteroid after Velma, and a stellar nursery near Cygnus “The Mystery Machine”. As punishment all references to the moon were stricken from official records.