SOLAR SYSTEM

How Did That Crater Get Its Name?

- from Red Planet Connection, October 1998

Nomenclature (no-men-clay-chur): A system or way of naming things or places.

Human beings are interesting creatures. We like to name things. We attach names to everything that walks and grows around us, flies above us, or crawls and swims below us. Even in ancient times, people named the stars, constellations, and planets that they observed in the night sky.

All of the planets in our solar system, except for Earth, are named after Roman or Greek gods. For example, the planet Mars was named by the Romans after their god of war. The god Mars was known to enjoy bloody warfare and violence. The symbol for Mars represents a shield and a spear, weapons fit for the god of war.

When humans began observing the Red Planet with telescopes in the 1800s, they viewed distinct areas and features. When they started making maps of Mars, it became necessary to name regions of the planet.

An Italian astronomer named Schiaparelli created some of the first maps of Mars. He named features using words from biblical and mythical geography. Some of these names, such as Argyre, Hellas, and Tempe, are still used on maps and globes of Mars.

In the 1970s, after the Mariner spacecraft flew by Mars, many new images were returned to Earth. A special group of people was formed to decide on names for the newly discovered features. This group also set up rules for naming future discoveries.

All features on Mars have two names. The first is a formal name following the international rules that have been established. The other is a geologic name. The second name tells us what type of geologic feature it is. Following are some examples of geologic names:

Mons: mountain
Crater: circular depression
Dorsum: ridge
Planum: plateau or high plain
Fossa: depression (hole)
Valles: valley

For example, Olympus Mons is a mountain formed by a volcano. It is named after Mount Olympus in Greece. Sometimes the name order is reversed. For example, in Valles Marineris, the geologic name comes first. Valles Marineris is a valley named after the Mariner spacecraft that first flew by Mars.

Anyone can submit a name for a specific feature on Mars! The group meets once each year to consider appropriate names. If you would like to suggest a name for a feature on Mars, send your suggestion to the U.S. Geological Survey, Branch of Astrogeology, Room 409, 2255 N. Gemini Drive, Flagstaff, AZ 86001.

New missions to Mars typically result in the discovery and naming of new features. The Mars Pathfinder landed in the Ares Vallis on Mars in July 1997. Lots of rocks were named.

The Mars Pathfinder team decided to have a little fun. They named some of the interesting rocks at the landing site after cartoon characters that the rocks resembled. The rocks became known as Casper, Yogi Bear, Scooby Doo, and countless other wacky characters.

Rules for Naming Martian Features

Large craters are named after deceased scientists who have contributed to the study of Mars.

Gusev (Maturei M., 1826-1866, Russian astronomer)
Lowell (Percival, 1855-1916, American astronomer)

Small craters are named for villages and towns of the world with populations less than 100,000.

Aspen (Town in Colorado, USA)
Bira (Town in Russia)
Isil (Town in Spain)
Jama (Town in Tunisia)
Kakori (Town in India)

Large valleys are named for the word used for Mars in various languages of the world.

Ares Vallis (word for Mars in Greek)
Mangala Valles (word for Mars in Sanskrit)
Marte Vallis (word for Mars in Spanish)
Mawrth Vallis (word for Mars in Welsh)
Nirgal Vallis (word for Mars in Babylonian)
Tiu Vallis (word for Mars in Old English)

Small valleys are named for classical or modern names of rivers.

Indus Vallis (river in Pakistan)
Naktong Vallis (river in Korea)
Warrego Valles (river in Australia)

All other features retain the names given by Schiaparelli or Antoniadi, another Italian astronomer.

Amazonis Planitia (classical name)
Libya Mons (classical name)
Olympus Mons (classical name)

Rules for Naming Craters

Naming rules exist for most features on planets, moons, and asteroids. The following are the regulations for craters:

Craters on Mercury are named after famous deceased artists, musicians, painters, or authors.
Large craters on Venus are named after famous women.
Small craters on Venus are given common female first names.
Large craters on Earth's moon are named after famous deceased scientists, scholars, or artists.
Small craters on the moon are given common first names.
Craters on Jupiter's moon Europa are given names of Celtic gods and heroes.
Craters on Jupiter's moon Ganymede are named for gods and heroes of the ancient Fertile Crescent people.
Craters on the asteroid Ida are named for caverns and grottos of the world.

Nomenclature information courtesy of U.S. Geological Survey and International Astronomical Union.