Mars and Spica. Optical image of the planet Mars (orange, lower left) next to the bright star Spica (Alpha Virginis). North is at top. Mars appears orange as its surface is covered in a red rocky desert, which takes its colour from iron- rich compounds similar to rust. It is the fourth planet out from the Sun, and takes 687 days to complete one orbit. Spica, in the constellation Virgo, is the 16th brightest star in the sky excluding the Sun. Photographed on the 9th June 1999, when Mars was at its closest to Spica.