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LOCATION: Fourth rock from the sun
DISTANCE FROM THE SUN: 128,409,598 to 154,865,853 miles (206,669,000 to 249,209,300 kilometers)
AVERAGE SURFACE TEMPERATURE: -81° F (-63° C)
LENGTH OF SPACE JOURNEY FROM EARTH TO MARS: 7 months
GRAVITY: If you weigh 100 pounds (45 kilograms) on Earth, you’d weigh 38 pounds (17 kilograms) here.
Astronomers peering at Mars in the 17th and 18th centuries saw signs of life everywhere. Seas! Continents! Canals that carried water to Martian farms! You spot none of these features as your spaceship deploys its parachutes for touchdown on this cold desert world—but then you never expected to. Mars has been the subject of many myths; you intend to separate science fact from science fiction as you step on the surface of the red planet.
For starters, the red planet isn’t even totally red! Browns, tans, golds, and flecks of green pop out as you scan the rocky, dusty, dune-laden landscape. Mars only looks red from far away because of rusting iron minerals in the rocks and soil. The soil blows into the air (occasionally in planetwide dust storms) to give the atmosphere a bloody tint. Water may have flowed on Mars long ago, in ancient seas and riverbeds that early astronomers confused for canals. That was back when the atmosphere was thicker. Now, the air here (mostly carbon dioxide) is too wispy to support water or hold much heat. If you took off your spacesuit and stood on the equator at high noon, your toes would feel toasty but your face would be freezing! The good news is summer here lasts for six months. The bad news: So does winter!
• The surface and orbit of Mars bustles with robotic vehicles and probes that are mining the planet for all sorts of info—including signs of life (none have been found so far).
• Mars is home to one of the largest canyons in the solar system (big enough to swallow the Grand Canyon) and the tallest volcano, Olympus Mons, which is nearly three times as tall as Mt. Everest.
• Radio listeners who tuned in late to a 1938 Halloween broadcast of H.G. Wells’ science-fiction book War of the Worlds thought the program was a genuine news report of a Martian invasion!
• In 2015 scientists confirmed water flows on Mars, raising questions about whether life could exist on the red planet.