What Is Mars?
Mars is the fourth planet in the Solar System and is located between Earth and Jupiter, the third and fifth planets from the Sun, respectively. Also known as the "Red Planet," Mars appears to have a reddish hue due to significant amounts of iron oxide, which is red, on the surface of the planet. For this reason, it is easier to differentiate Mars from other bodies in the galaxy with the naked eye. In terms of size, Mars is the second-smallest planet in the Solar System, and has a diameter that is half the size of Earth's. Additionally, the planet has a lower density than Earth, which is why the gravity on Mars is less than that on Earth. Unlike Earth, which only has one moon, Mars has two moons: Phobos and Deimos.
History and Etymology
Ancient Egyptian civilizations first identified Mars as a wandering object in space in 1534 BCE, and noticed that it appeared to move in the opposite direction of other planets, which is called retrograde motion. Advances in astronomy by the time of the Neo-Babylonian Empire enabled Babylonian astronomers to determine that Mars made 42 circuits of the zodiac (or 37 synodic periods) every 79 years. Additionally, ancient Greek astronomers, including Aristotle, were studying Mars by the fourth century BCE.
The name "Mars" stems from the ancient Romans, who had identified seven bright objects in the sky. These objects were five bright planets, as well as the Sun and Moon. Roman astronomers named these planets after Roman gods, and Mars was named after the Roman god of war. The planet's two small moons, Phobos and Deimos, were named after the two horses that the God of War used to pull his red chariot. Phobos and Deimos translate to "fear" and "panic," respectively.
In other cultures, the planet is referred to by other names, such as Ares by the Greeks. According to Greek Mythology, Ares was the God of War. China called the planet "The Fire Star," while the Egyptians identified it as "Her Desher," which translates to, unsurprisingly, "the red one." Most cultures have associated Mars with masculinity and strength. In fact, the symbol used to denote the male gender is the symbol of Mars, which is a circle with an arrow in the upper right region. The arrow is attached to the circle and points outward.
Exploration missions to Mars were attempted as early as 1960. The earliest missions were launched by Soviet (OKB-1) and American (NASA) space programs, and then decades later by other countries including Japan, China, and India. These explorations have contributed to increased knowledge about Mars. An example of a successful mission is Mars Global Surveyor (MGS), launced by NASA from 1996 until 2006, which created maps of the entire planet, including both the atmosphere and surface.