The Martians are coming! Actually, they’ve been here for a long time, sort of. The ancient Egyptians were already observing the red planet in the 2nd millennium BCE, while the Chinese were recording its motions. Babylonian astronomers devised a way to predict its future positions, and Greek, Indian and Islamic philosophers all weighed in on different aspects of the celestial sphere. The amount of information gleaned on Mars in antiquity served as the basis for modern science to take over the study of this planet with great success. Now, for example, we know that the Martians won’t be coming at all since there are none, and the only denizen of Mars is, well, Mars, the god of war, also known as Ares in Greek, and long gone from this and any other world, religious or not. But the fertile myths and fantasies that the planet Mars has inspired, has filled humanity with wonderment, dread and, yes, hope of life elsewhere in the universe. And that’s why Orson Wells’ 1938 War of the Worlds broadcast was such a frightening hit. Here are some things you should know about Mars.