From Universe Today A year on Mars lasts almost 689 days. In other words, a Martian year is 1.88 times as long as an Earth year. For every time Mars completes a single orbit around the Sun, Earth has almost gone around twice.
A Mars Opposition occurs when planet Earth passes in between the Sun and planet Mars. Because of their orbits, this situation happens about every 2 years and 2 months – 779.94 to be precise.
During this opposition time, Mars becomes one of the brightest objects in the night sky. Easy to see with the unaided eye, and very large and bright in a small telescope. With a better telescope you can even make out features on the surface of the planet, and even the polar ice caps.
Want to organize your schedule for the next time Mars will be close to Earth? Here are some upcoming dates:
May 22, 2016
July 27, 2018
October 13, 2020
December 8, 2022