The red appearance of the planet Mars is caused by oxidised iron on its surface - basically rust. The ancient Egyptians were the first to name it after its colour. They called it 'Har Decher', the Red One. The Assyrians called it the 'Shredder of Blood'. The Greeks called it Ares and the Romans called it Mars - in both cases the names of their gods of war.
The two moons of Mars were discovered by American astronomer Asaph Hall in 1877 and named Phobos (fear) and Deimos (panic), after the horses that pulled the chariot of the Greek god of war.
The average temperature on Mars is -63°C.
Belief in intelligent life on Mars was fuelled by the mistaken claim in 1877 of Italian astronomer Giovanni Schiaparelli that he had discovered canals on its surface.
The temperatures on Mars vary between -130°C and +20°C. The atmospheric pressure is less than one per cent of that on Earth, so, even at those low temperatures, water would instantly boil into vapour. A day on Mars lasts 24hr 37min - almost the same as an Earth day - but a year is 686.7 Earth days. Utopia is a large, smooth lying area of Mars.
Mars has the biggest volcano in the Solar System, Olympus Mons - large enough to cover Spain, and three times the height of Everest. If you weigh 150lb on Earth, you will weigh 57lb on Mars.
In a controlled experiment performed by psychologists in Cambridge in 1982, only one rat out of eight preferred a Mars bar to cheddar cheese.
Economists have used the "Mars Bar Standard" to compare prices in terms of the number of Mars bars something costs. A Rolls Royce is 347,000 Mars bars.