What’s in an astronomical name?

By Tom Burns - Stargazing

The science of astronomy likes to think that it is above the political and social battles that seem to rule our everyday lives these days. Most stars have alphanumerical or designations, not names. The goal is to be objective. The universe is deaf to human social problems and history. Science attempts to understand the universe, not to impose human foibles upon it.

That’s not to say that scientists aren’t under some political pressure to reflect the political beliefs of their patrons in the Federal government. Hard evidence convinced most NASA scientists that climate change is real. Many of them became persuaded from the early days when climate change was called “global warming.”

However, they are under pressure from powerful political and economic forces to say that the evidence is inconclusive. During the Bush administration, many of them looked at NASA’s multi-billion-dollar budget and stood mute. Now, their pleas are simply ignored by some politicians.

Such transgressions stretch backward into history. Until recently, scientists did not depend on Federal institutions like the National Science Foundation and private organizations to fund their research. Instead, they depended on patrons, rich and powerful individuals, to put food on their tables.

Such was the case for even the most famous of astronomers. For example, if the great Galileo Galilei had his way, the four brightest moons of Jupiter would be called the Medician Stars.

Look for Jupiter right now as a bright point of light high in the south amidst the much dimmer stars of Libra, the Scales, and quite near to one of Libra’s signature stars, the oddly named Zubenelgenubi.

Even simple pair of binoculars will usually reveal at least three of the four Medician Stars lined up around the planet.

In 1605, Galileo had been a mathematics tutor for Cosimo de’ Medici, son to the Grand Duke of Tuscany. In 1609, Galileo discovered with his telescope four points of light near Jupiter. They seemed to accompany the planet as it moved across the sky.

Coincidentally, Cosimo became Grand Duke around the same time. In order to gain financial support from his former pupil, Galileo proposed that the moons be named Cosimo’s Stars.

Cosimo demurred, however. He instead insisted that the moons be named the Medician Stars in honor of his three brothers and, of course, himself.

The weight of history and the derision of other astronomers eventually prevailed. In the end, Galileo, who had an ego the size of the enormous planet and its moons combined, would have been pleased. The moons are called the Galilean Satellites to this very day.

However, in a burst of objectivity and (probably false) modesty, Galileo wanted simply to number the individual moons, but I, II, III, and IV just don’t cut it emotionally. Humans love to name things. Letters and numbers just don’t have the public-relations impact of a well-chosen name.

The solution seems obvious in retrospect. After all, the academicians and scholars of the time were classically trained. They didn’t believe in the old Roman and Greek gods, but they were familiar with ancient mythology. They had read — in the original Greek and Latin, no less — the old stories about the ancient gods and the poets and scholars who wrote about them. Their severe, knuckle-busting teachers saw to that.

The tendency to think first of the defunct classical deities when naming solar-system objects continues, rather oddly, into the twenty-first century. Astronomers named one of the dwarf planets Eris after the goddess of strife and discord. Given the intense controversy surrounding the exclusion of Pluto and Eris from the list of “main” planets, the choice of the war-like goddess was, well, apt.

The choice of Greek and Roman gods has a limit that Renaissance astronomers could never have envisioned. Modern planetary scientists expect to discover more than a hundred dwarf planets. There simply aren’t enough classical gods to satisfy the need for names.

Luckily, cultures around the world have generated their own sets of gods. Thus, we begin to see names like Haumea, the Hawaiian goddess of fertility and childbirth, and Makemake, the creator of humanity and the god of fertility to the ancient inhabitants of Easter Island. Of astronomers’ seeming obsession with procreation, I shall remain mute.

Naming moons created a different set of problems. The moons orbited Jupiter and thus were not planets in their own right.

Around the same time, astronomer Simon Marius had discovered the same moons independently. He suggested they be called Io, Ganymede, Callisto, and Europa after very close personal “friends” of the god Jupiter (if you know what I mean and I think you do). Since both the mythological figures and the moons “revolve” around Jupiter, Marius’s name stuck.

Oddly, even the word satellite, the technical term for such an object, took some time to develop. We tend to take such words for granted as if the gods lowered them down from heaven on a string. But remember that until Jupiter’s moons were discovered, only one object in the universe had a moon. Earth’s moon was the moon.

Now there were four more. The new category needed a name. The moons obviously weren’t stars, so the “stars” part of “Medician Stars” was definitely out. One of Galileo’s disciples suggested Cosmipharus, again in honor of Cosimo, but that name kept the patronage angle intact. Apparently, no other astronomers wanted financial help from the Grand Duke. Besides, the term doesn’t really explain what the moons were doing there.

Johannes Hevelius suggested Jovis Circulatores, circulators or orbiters of Jupiter, which describes exactly what moons do around planets, but it doesn’t maintain the mythological angle. He also suggested Jovis Comites, companions of Jupiter. That one should have stuck, but it didn’t.

French mathematician Jacques Ozanam had the final say. He called them “satellites” from a Latin word meaning “escorts,” presumably of both the god and the planet.

Technically speaking, I suppose that it is incorrect to call the Jovian satellites “moons,” but the common usage of the term “moon” remains for the satellites of all the satellites of all the planets of our solar system.

I have no complaints about that usage. It seems strange to refer to Earth’s lonely satellite as the moon when there are so many of them in the solar system. If we are to remain consistent, it seems far more correct to refer to our moon by its real name, Luna, the Roman embodiment of our moon.

Thus, the planet Jupiter, a giant liquid ball, is named after a rapacious, if defunct, god. Its brightest moons are named after his illicit lovers. Satellite, the technical term for those — and all — moons of planets continues to have its obscurely mythological connection in our distinctly non-mythological modern world. In fact, one of the current meanings of “escort” has taken on a rather racy connotation.

Perhaps it is time to go back to the old way of naming astronomical objects after the kind patrons who give astronomers the money to ply their research. I now formally propose that the Galilean Satellites be renamed the Microsoftian Moons. Or how about the Wexnerian Worlds? The Gatesian Globes? I do so in the name of my former institution, Perkins Observatory, which is badly in need of the funding.


By Tom Burns


Tom Burns is the former director of the Perkins Observatory in Delaware.

Tom Burns is the former director of the Perkins Observatory in Delaware.