You may have heard the news about how the crew of NASA’s Artemis II mission named a crater on the Moon “Carroll.” The name honors Carroll Wiseman, the late wife of the mission’s commander, Reid Wiseman. It was a moving, heartfelt moment, showing how impactful it is that astronauts bring their full humanity into exploration. It might also make you wonder: who gets to name things in space, and how does it work?
The short answer is that every new name for a natural object in space is decided by the International Astronomical Union.
The long answer is much more interesting.
Gods in the skies
The very first planetary bodies to be named were those visible to humans thousands of years ago, long before the International Astronomical Union (IAU) got involved.
Aside from Earth, the Moon, and the Sun, which were given names in the earliest languages, the first planets to be named were those clearly visible in the night sky with the naked eye: Mercury, Venus, Mars, Jupiter, and Saturn.
These planets have different names around the world, often linked to mythology. In some East Asian languages, their names relate to the five elements — Mercury as water, Venus as metal, Mars as fire, Jupiter as wood, and Saturn as earth.
In English, as well as many European languages, the visible planets are named after Roman deities. This stems from ancient Greek culture, in which each planet was deemed sacred to a particular god based on compatible characteristics. The planet that moves across the sky the most quickly, for example, was associated with the swift messenger for the gods. The fiery red planet was associated with the angry god of war.
Ancient Roman culture adopted this tradition from the Greeks, assigning each planet to the corresponding god from their own mythology — Mercury, the messenger god; Mars, the god of war, etc.
Because Roman culture and language dominated Europe for centuries, these names made their way into most modern European languages.
New worlds, ancient names
When the telescope was invented, astronomers started finding new objects in need of names — moons of Jupiter and Saturn, the more distant planet Uranus, and more.
At first, astronomers wanted to name their finds after the patrons who supported their work. Galileo Galilei wanted to name Jupiter’s four major moons, which he discovered in 1610, after the wealthy Medici family. When Giovanni Domenico Cassini spotted several of Saturn’s moons in the late 1600s, he called them Sidera Lodoicea (“Stars of Louis”), honoring King Louis XIV of France. In 1781, when William Herschel discovered Uranus, he wanted to name it after England’s King George III.