♂ Mars

Named for the Roman god Mars (Greek: Ares)

War Farmland The Roman army

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Mars by Diego Velázquez
Mars Diego Velázquez, c. 1640 Museo del Prado, Madrid Mars sits wearing a helmet, with a shield and armor on the ground at his feet. Public domain, via Wikimedia Commons

The god of war and guardian of farmland, and the father of Rome’s founders.

The god

Mars was the Roman god of war and also a guardian of farmland, a combination typical of early Rome, and the foremost of the Roman army’s gods. He was the divine father of Romulus and Remus, the founders of Rome, and his sacred animals were the woodpecker and the wolf; a she-wolf nursed the twins. Most of his festivals fell in March, the month named for him, and in October, the start and end of the season for war. Each March his priests, the Salii, went in procession around the city, dancing and singing, in charge of twelve bronze shields; legend said the first fell from heaven in the reign of King Numa. The Campus Martius, the “Field of Mars,” took its name from him, and Augustus built a temple to Mars Ultor, “Mars the Avenger,” in 2 BCE.

How the planet got its name

The Romans named the planet for their god of war because its reddish color reminded them of blood; the Egyptians called it Her Desher, “the red one.” Babylonian astronomers associated it with their god Nergal. Its two small moons, discovered by Asaph Hall in 1877, are Phobos and Deimos, named for twin sons of Ares; Phobos is the god of fear and panic.

Symbols

Spear Helmet Shield Wolf Woodpecker

The planet

A cold desert world with a very thin atmosphere, mostly carbon dioxide, nitrogen and argon. Iron minerals in its dirt rust, which makes it look red. Mars has seasons, polar ice caps, extinct volcanoes and canyons, including Olympus Mons, the largest volcano in the solar system, which dwarfs Mount Everest, and Valles Marineris, a canyon system long enough to stretch from California to New York. Ancient river valleys, deltas and lakebeds show that it once had water.

Diameter
6,792 km 0.53 × Earth
Mass
0.642 × 10²⁴ kg 0.11 × Earth
Gravity
3.7 m/s² 0.38 × Earth's
Length of day
24.7 hours sunrise to sunrise
Length of year
687 Earth days one trip around the Sun
Distance from the Sun
228 million km 1.52 AU (Earth = 1)
Average temperature
-65 °C -85 °F
Moons
2
Rings
No

Figures from NASA’s Planetary Fact Sheet; the temperature is its “mean temperature.” Comparisons with Earth are worked out from the same sheet.

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