欧博娱乐The Planetary Society
Spotting Mars at night
Mars can be seen from Earth with the naked eye. As the fourth planet from the Sun, it is one of the closest worlds to Earth and one of the brightest planets in the Solar System. Venus and Jupiter are typically the only planets brighter than Mars in the night sky.
You can spot the planet Mars by its distinctive red color. Some ancient peoples associated this color with blood and named Mars after their god of war. Today, we use the name of the Roman god of war to describe Mars itself, but the Greek names of two figures related to Mars, Phobos and Deimos, to describe the planet’s two moons.
Humans have sent more spacecraft to Mars than any other planet beyond Earth. Today, there are several missions operating on or around the planet.
The United States and the Soviet Union both began trying to send robotic probes to Mars in the 1960s. Each country failed at first. Then, in 1965, NASA achieved a milestone when its Mariner 4 spacecraft became the first to successfully fly by Mars. The probe revealed a barren landscape, but later Mariner missions refined that picture. NASA’s Mariner 9, for example, spotted Mars in the throes of a giant dust storm that covered almost the entire planet. After the dust storm cleared, Mariner 9 discovered Valles Marineris, the largest canyon in the Solar System. The eventual discovery of other dry canyons, deltas, lakebeds, and river valleys would go on to suggest that liquid water once flowed on the Martian surface.