Nomenclature rules can disrupt planetary scientists' fun, but they serve a purpose.

After the Soviet spacecraft Luna 3 retrieved the first pictures from the far side of the Moon in 1959, the justifiably proud Soviets started to call one of the lunar lava plains Mare Moscoviense, after their capital. The move seemed to defy a decades-old tradition that such maria are named after mental states (Tranquillitatis, for example, or Serenitatis), or words for water. At the 1961 meeting of the International Astronomical Union (IAU), French astronomer Audouin Dollfus was able to restore tranquillity in the astronomical community with a serene move. Moscoviense worked as a name, he said, because Moscow is, in fact, a “state of mind”.

To avoid further disputes as proud pioneers sought to thank benefactors, curry favour or merely indulge themselves, the IAU went on to establish working groups to set rules and conventions for nomenclature.

Procedures now make sure that mountains on Mercury are named with words for 'hot' in various languages, canyons on Venus christened after goddesses and small craters on Mars twinned with villages on Earth. Just last month, a 39-kilometre-wide Martian crater was named Moanda, after a town in Gabon.

However, as the News story on page 442 makes clear, those who seek to explore often remain (pleasingly) reluctant to follow the rules. The disputes are minor, but it is no surprise that those scientists working on NASA missions to Mars and Vesta, flushed with discovery, are annoyed by the apparently hidebound rules of the IAU. The row over Vesta centres, quite literally, not on a name but on issues of how to apply systems of longitude and latitude and mapping coordinates. On Mars, NASA researchers have taken to calling a prominent mountain that will be tackled by their Curiosity rover Mount Sharp, after a late colleague, rather than using the official title, Aeolis Mons.

Still, rules are rules. What's in a name? Quite a lot, actually. Think how it would have been had the namers of planets not yielded to tradition. After discovering Uranus in 1781, astronomer William Herschel wanted to name the planet after George III, the king of Great Britain. And what a loss that would have been to generations of sniggering schoolchildren.

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