Recently Google has expanded its online mapping services, offering ordinary users the chance to explore the surface of an alien planet for the very first time. Google Mars allows users to view the surface of the Red Planet either by a colour coded altitude map, black and white photographs, or an infrared map. The launch follows the success of Google Earth, which allows detailed exploration of the earth’s surface. Another service, Google Moon, lets users view the sites of moon landings. The maps used on Google Mars were made from images captured by Nasa probes Mars Odyssey and Mars Global Surveyor, both currently orbiting the planet. Google launched the service to mark the 151st anniversary of the birth of Percival Lowell, an astronomer who mapped and studied Mars in the 19th century.