A Crater By Any Other Name

It’s been just over two weeks since the MESSENGER spacecraft swooped past Mercury during its second flyby of the innermost planet.

Since the initial fervor, the MESSENGER team has been faithfully releasing images collected during the close encounter, some of which are providing data-hungry scientists with fodder for speculation about Mercury’s geologic processes.

Today’s offering highlights what I think must be one of the more frustrating aspects of being a planetary explorer: naming stuff.

Where in the universe—other than your local Barnes & Noble—can you find Arabic, Swiss, Ukrainian, and ancient Roman poets sitting next to a Baroque-era French composer being cut in half by one of Captain Cook’s ships?

That’d be Mercury’s southern side, which is just packed with craters first seen during the original Mariner 10 flybys in 1974 and ’75.


—Image courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Now, gone are the days when being the first person to see something and, whenever possible, stick a flag in it grants you the automatic right to bestow upon it a name. In astronomy they’s got rules, and the rules for naming things can get pretty specific.

[Thank goodness for this, by the way, or the list of gas giant planets in our solar system might have been Jupiter, Saturn, Neptune, and George.]

For Mercury, the International Astronomical Union states that all craters must be named for famous dead artists, musicians, or writers. Rupes, or cliffs, are named after famous explorers’ ships.

Given these constraints, creating the list of approved crater names on heavily pockmarked Mercury must have really stumped even the most ardent trivia fans.

Consider too that most of these monikers were decided before we’d even gotten to see more than 45 percent of the planet’s surface.

In April the IAU added six crater names to Mercury’s approved list, and more are sure to come as the onslaught of MESSENGER images gets scrutinized.