Mars 101

Cold and distant

Mars is a cold, dry, desert landscape of sand and rocks (Figure 1). Many land features on the present-day surface of Mars, such as volcanoes, canyons, and valleys, make it look very similar to Earth, but humans could not survive in the present environment on Mars. The average surface temperature is -63 degrees C (-81 degrees F), and nighttime temperatures on Mars can plunge to -110 degrees C (-170 degrees F). By comparison, the lowest temperature ever recorded on Earth was -89 degrees C (-130 degrees F) at Vostok, Antarctica in July, 1983. One reason Mars is much colder than Earth is its distance from the Sun. On average, Mars orbits the Sun at a distance of about 228 million km (about 142 million miles). This is about 1.5 times farther from the Sun than the Earth. Mars’ greater distance from the Sun also gives it a longer orbital period, or year. One year on Mars is 686 Earth days (Figure 2). Although one Mars year is almost twice as long as an Earth year, Mars’ rotational period, or day, is only 40 minutes longer than the Earth’s.