The Red Planet was named after the god of war. The reddish color reminded people of blood.
According to Roman myth, Mars rode on the chariot pulled by two horses named Phobos and Deimos. The two small moons of Mars are named after these two mythical horses.
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Discovery
Mars is very bright in the sky and can be easily seen. Therefor, it is unclear who the first person was to discover the planet.
Specific discoveries were later made on the planet due to astronauts visiting the surface.
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Mars Compared to Earth
Mars (diameter 6790 kilometers) is only slightly more than half the size of Earth (diameter 12750 kilometers).
Mars' mass is 6.42 x 1023 kilograms, about 10 times less than Earth.
Since Mars has less mass than Earth, the surface gravity on Mars is less than the surface gravity on Earth. The surface gravity on Mars is only about 38% of the surface gravity on Earth, so if you weigh 100 pounds on Earth, you would weigh only 38 pounds on Mars.
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Mars Compared to the Sun
Mars' average distance from the Sun is roughly 230 million km (1.5 AU) and its orbital period is 687 (Earth) days. The solar day on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds.
Mars is 4.603 billion years old.
Mars has an average orbital speed 24 km/s.
Mars is the fourth planet from the Sun and orbits the Sun at an average distance of approximately 141 million miles
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Seasons on Mars
There are the familiar winter, spring, summer and fall, caused by the planet's tilt.
There are also two additional seasons, aphelion and perihelion, which occur because of Mars' highly elliptical orbit.
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Mars’ Atmosphere
The Martian atmosphere consists of approximately 96% carbon dioxide, 1.9% argon, 1.9% nitrogen.
The atmosphere is dusty, giving the Martian sky a light brown or orange-red color when seen from the surface.
Mars's atmosphere is composed of the exosphere, the upper atmosphere, the middle atmosphere, and the lower atmosphere.
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Mars’ Temperature
Average -81 degrees F - compared to Earth’s average temperature of 57 degrees F.
It can also vary from minus 195 F near the poles during the winter, to as much as a comfortable 70 F at midday near the equator.
At times, it even snows on Mars. The Martian snowflakes, made of carbon dioxide rather than water, are thought to be very small particles that create a fog effect rather than appearing as falling snow.
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Surface Features
The Martian surface has some large canyon systems, the largest being the Valles Marineris.
Mars has polar caps that wax and wane with the Martian seasons.
At one time Mars had 3 large volcanoes, but these are now extinct.
The atmosphere of Mars is thin, but it supports high velocity seasonal winds that are correlated with solar heating of the surface and that produce dust storms that lead to a lot of surface erosion