From the May 2015 issue

Send astronauts to Zappafrank

Exploring how we name the universe.
By | Published: May 25, 2015 | Last updated on May 18, 2023
Celebrities know that names have power. That’s why Robert Zimmerman and Cherilyn Sarkisian decided to call themselves Bob Dylan and Cher. Yet little poetry or stateliness was employed when it came to naming the universe’s contents. Indeed, astronomy possesses the most inconsistent nomenclature in all of science. Here’s a primer for newbies — and a refresher for the rest of us.

The brightest stars enjoy proper names, though just a few dozen remain in use today. Some have punch, like Sirius and Arcturus. Such names also serve to recall ancient mythologies. Medium-bright stars are referenced by a different system created in the 17th century, when 1,564 stars got mostly Greek letter designations, like Gamma (γ) Arietis.

The majority of stars — over a million have been cataloged — remain unnamed or at best possess long strings of license plate-like letters and numbers. The star orbiting the black hole Cygnus X-1 is HDE 226868 but also called BD+34 3815.

Move to the planets (beyond ours), and we get the names of Roman gods, although Uranus came from the Greeks. As for planetary features, major ones sport kindergarten labels like Neptune’s “Great Dark Spot” and Jupiter’s “Great Red Spot.” But smaller features like valleys possess disparate mind-numbing designations. Who’s responsible for that?

The International Astronom­ical Union (IAU), that’s who. The IAU is alone empowered to name the contents of the cosmic supermarket. Newly found mountain chains, craters, and the like follow the IAU’s strict guidelines. Its rules fill pages and pages. Consider a few of Saturn’s moons.

Different feature types have different naming requirements on Titan. For example, craters are named for gods of wisdom, while mountain peaks come from J. R. R. Tolkien’s fictional Middle-earth mountain ranges. All features on Iapetus must bear the names of people and places from Dorothy Sayers’ translation of La Chanson de Roland. Those on Rhea must be people and places from creation myths, while ones on Mimas must be people and places from Sir Thomas Malory’s Le Morte D’Arthur legends, specifically the 1962 Keith Baines translation. And on it goes. No movie stars or cartoon characters.


Moons named before the IAU arrived on the scene display an enjoyable inconsistency. The martian satellites Phobos and Deimos (the Greek personifications of fear and dread, respectively) take the “most depressing” prize. Uranus’ moons are mostly characters from Shakespearean plays, which is why there are actual celestial bodies named Puck and Juliet.

As for our Moon, many of the dark blotches or “seas” are bizarrely named for emotions (Sea of Tranquillity, Sea of Cleverness) or weather phenomena (Ocean of Storms, Sea of Clouds). Features on the lunar backside have Russian names, the embarrassing result of that country’s Luna 3 arriving there first, in 1959. As for Full Moons, TV newscasters sometimes urge viewers to watch the upcoming “Wolf Moon” or “Strawberry Moon.” But only the Harvest and Hunter’s Moons are official names. The 12 or 13 yearly Full Moons labeled by various Native American tribes are contradictory and mostly ignored, like this month’s Buck Moon.

Asteroids are another story. They started out derived from Roman and Greek mythology but then changed over to a free-for-all, with names proposed by the discoverer and approved by the IAU. Only 5 percent of numbered asteroids have names, a motley assortment of people and even their relatives. You’ll find asteroid 3252 Johnny (for Johnny Carson) and 3834 Zappafrank. Mainstream scientists were favored, but not controversial or unpopular ones. Classical asteroids are there too, like Eros. Craters on Eros are labeled for “mythological and legendary names of an erotic nature.” How did that category make it through the stodgy IAU council? Must’ve been a late-night session.

Meteor showers are named for constellations, meteorites for whatever place on Earth they smashed into. Comets are the only objects named for their discoverers, who then become the sole authority on the pronunciation.

The floating Rorschach tests called nebulae do not generally receive new names. But we retain the labels bestowed in olden times. Long ago, someone thought one gas cloud looked like a dumbbell from the weight room at the local gym, a place not generally frequented by astronomers. The “Dumbbell Nebula” label stuck, as did the results of early astronomers saying, hey, look at that: An Eskimo! And there’s a Crab!

As for the universe’s largest structures — galaxies — some 200 billion are visible and millions cataloged, but only a couple dozen are named. These star cities are honored by things like a hat (the Sombrero Galaxy), an injury (the Blackeye Galaxy), and a tobacco product (the Cigar Galaxy). But the vast majority merely have number designations like NGC 6217.

Obviously there’s a sizeable gap between the cosmos’ inspirational contents and its odd or mundane labels. Few beginners would be inspired upon hearing of a “B ring” or galaxy “NGC 205” in the “Local Group.” Nonetheless, this hodgepodge system is not going to change, and even has a strange appeal. It’s shared by no other science. As astronomers, we affectionately know that it’s ours alone.

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