Published on: 14 Jan '09Published in: Astrophysics
Mars has surely been scrutinised since the dawn of humankind. In the 16th century Tycho Brahe made accurate observations of the position of Mars that enabled Johannes Kepler to obtain his first two laws of planetary motion. In the 17th century the first telescope observations were made, but very little surface detail could be discerned. Throughout the 18th and 19th centuries telescopes improved, revealing many dark areas on the red tinted surface. After the close opposition of 1877 Giovanni Schiaparelli announced about 40 canali on Mars. This led to the saga of the canals of Mars, laid to rest in 1971 when Mariner 9 made observations from Martian orbit showing that the canali/canals of Mars do not exist. Belief that there was life on Mars was widespread in the 19th century, including the view that the dark areas were some form of plant life. This view persisted until Mariner 4 flew past Mars in 1965 and discovered a far thinner atmosphere than previously thought, with impact craters dominating the images. It was Mariner 9 that revealed much more promising landscapes. Thus, the contemporary era of Mars exploration began. Our picture of Mars today is not only much more complete that that before Mariner 4, in several ways it is quite different. The belief however, that there may be life on Mars persists - subsurface life cannot be ruled out and, failing that, there might be ancient fossils on Mars.