On November 28, 1964, the Mariner 4 spacecraft was launched. It continued on toward Mars and was the first probe to return close range images of that planet. As a result of this successful mission, November 28 is known as Red Planet Day. So let’s take a few minutes to learn a bit about Mars.
The planet Mars has been known since antiquity, and its rusty color gave our ancestors the idea that it was associated with blood and, by extension, the god of war.
In more modern times, the telescope was used to try to study Mars. One notable scientist was Giovanni Schiaparelli. Because Mars, even when at its closest to Earth, appears much smaller than the Moon (about 1.3% the apparent size of the Moon), it is difficult to see detail on Mars from Earth. When humans look at something near its resolution limit, the brain tends to “fill in the gaps” and create optical illusions of lines and features that aren’t really there. Schiaparelli used the word “canali” to describe some of the lines he thought he saw. The word “canali” means “channel,” and due to a mistranslation, was translated as “canals.” Suddenly Mars had canals and the speculation about life on Mars began. Intelligent lifeforms were struggling to survive on the dry desert world and must have built canals to funnel water from the polar caps to survive.
Well, today we know that the “canals” don’t exist, but many features on Mars are real and have been well studied, such as the largest mountain and valley in the solar system, Olympus Mons and Valles Marineris. Strange that some of the largest features in the solar system exist on a planet that is only about 1/3 the size of Earth. Its two moons are tiny by comparison, being irregularly shaped lumps of rock both less than 14 miles across.
The atmosphere of Mars is very thin (comparable to Earth’s atmospheric pressure at about 50,000 ft altitude), and what little there is is composed mainly of carbon dioxide. Temperatures are cold by comparison with Earth, with an average surface temperature near -53°F.
Recent efforts have sent a flurry of robotic missions to study one of Earth’s nearest neighbors. The most recent mission to Mars is the media favorite and nuclear-powered Curiosity Rover. This year, while you celebrate Red Planet Day, you can look up at Mars knowing that a car-sized robot from Earth is actively sending us information, much like the Mariner 4 mission did back in 1964.