The Red Planet is, in many ways, the planet that is most like Earth, which is probably why our science fiction is filled with
stories of Martians. Percival Lowell even drew maps of the canals built by Martians. In the early 20th century, an organization
offered a cash prize , (worth $300,000 in today’s dollars), to the person who first communicated with an alien civilization. But
Mars was excluded because, at that time, everyone knew that Mars was inhabited by intelligent creatures! Radio producer
Orson Welles managed to alarm listeners of his famous ‘War of the Worlds’ broadcast.
But our first close-up images of Mars from Mariner 4 were a little disappointing to those who imagine Mars to be inhabited.
Subsequent pictures have shown Mars to be a place that may have once been hospitable. It is now believed that Mars once had an
extensive ocean. Mars may have even had plate tectonics in the past.
Mars has approximately the same period of rotation as Earth. One synodic rotation is called a sol. What is the time on Mars at the Curiosity
rover right now? You can have the time on Mars displayed on your computer.
It has polar ice caps which consist of frozen water and carbon dioxide. We occasionally see clouds in Mars' thin atmosphere. In the spring on
Mars, the carbon dioxide in the polar cap sublimates and the increase in atmospheric pressure causes huge dust storms to form. Occasionally, one
sees dust devils moving across the surface. The surface temperature is never higher than about 10 degrees Celsius.
