Artificial structures visible from space
Artificial structures visible from space without magnification include highways, dams, and cities.
Whether an object is visible depends significantly on the height above sea level from where it is observed. The Kármán line, at, is accepted by the World Air Sports Federation, an international standard-setting and record-keeping body for aeronautics and astronautics, as the boundary between the Earth's atmosphere and outer space. However, astronauts typically orbit the Earth at several hundreds of kilometres; the ISS, for example, orbits at about above the Earth, and the Moon orbits at about away.
Examples
From US Space Shuttles, which typically orbited at around, cities were easily distinguishable from surrounding countryside. Using binoculars, astronauts could even see roads, dams, harbors, even large vehicles such as ships and planes. At night, cities are also easily visible from the higher orbit of the ISS.Metropolitan areas are clearly visible at night, particularly in industrialized countries, due to a multitude of street lights and other light sources in urban areas.
Cooling pond of Chernobyl
The long cooling pond of the Chernobyl Nuclear Power Plant is visible from space. In April 1997 it was photographed from the Mir space station, which was in orbit somewhere between and.The Greenhouses of Almería
The greenhouse complex that covers about in the province of Almería, Andalucía, Spain is visible from space. It is sometimes referred to as the "Plastic sea" due to the high concentration of these greenhouse structures.This area produces much of the fruit and vegetables that are sold in the rest of Spain and Europe. Apart from the area depicted in the photo, other zones of the province of Almería have large concentrations of white-plastic greenhouses too.
Bingham Canyon Mine
The Bingham Canyon Mine, more commonly known as Kennecott Copper Mine, is an open-pit mining operation extracting a large porphyry copper deposit southwest of Salt Lake City, Utah, in the Oquirrh Mountains. The mine is the largest human-made excavation in the world.Misconceptions
The Great Wall of China
The claim that the Great Wall of China is the only man-made object visible from the Moon or outer space has been debunked many times, but remains a common misconception in popular culture. According to astronauts Eugene Cernan and Ed Lu, the Great Wall is visible from the lower part of low Earth orbit, but only under very favorable conditions.Different claims were historically made for the factoid that the Great Wall is visible from the Moon. William Stukeley mentioned this claim in his letter dated 1754, and Henry Norman, 1st Baronet|Henry Norman] made the same claim in 1895. The issue of "canals" on Mars was prominent in the late 19th century and may have led to the belief that long, thin objects were visible from space. A viewer would need visual acuity 17 000 times better than the norm to see the Great Wall from the Moon.
The centimetre-band Spaceborne Imaging Radar of STS-59 and STS-68 was able to detect not only the Great Wall but also invisible buried segments of it.