Artificial structures visible from space

From US Space Shuttles, which typically orbited at around {{convert|135|mi|km|abbr=on}}, cities were easily distinguishable from surrounding countryside. Using binoculars, astronauts could even see roads, dams, harbors, even large vehicles such as ships and planes.[http://starryskies.com/articles/2003/10/earth.visible.html Starry Skies website] 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 (see light pollution).

File:Chernobyl from MIR.jpg in 1997]]

The {{convert|10|km|mi|adj=on}} 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 {{cvt|296|km|mi}} and {{cvt|421|km|mi}}.

File:Almeria-Invernaderos.jpg, Andalucía, Spain]]

{{Main|Intensive farming in Almería}}

The greenhouse complex that covers about {{convert|26|e3ha|e3acre sqmi|abbr=off}} in the province of Almería, Andalucía, Spain{{Cite web | url=http://geographyfieldwork.com/AlmeriaClimateChange.htm | title=A Greenhouse Effect has cooled the climate of Almeria}} is visible from space.{{Cite web | url=http://www.popularmechanics.com/home/improvement/lawn-garden/worlds-18-strangest-gardens-greenhouses-of-almeria#slide-5 |title = The World's 18 Strangest Gardens|date = 11 August 2010}} It is sometimes referred to as the "Plastic sea" ("Mar de plástico" in Spanish) 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 (and also the south of Spain) have large concentrations of white-plastic greenhouses too.

File:Bingham Canyon Mine from ISS 2007.jpg near Salt Lake City, Utah from the International Space Station in 2007]]

The Bingham Canyon Mine, more commonly known as Kennecott Copper Mine,{{cite web|last1=Mcfarland|first1=Sheena|title=Kennecott Copper Mine recovering faster than predicted|url=http://www.sltrib.com/sltrib/money/57068438-79/mine-kennecott-jones-rio.html.csp|website=The Salt Lake Tribune|access-date=28 April 2015}} 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.{{Cite web|url=http://www.deseretnews.com/article/865649211/Kennecott-laying-off-200-workers.html|archive-url=https://web.archive.org/web/20160304040259/http://www.deseretnews.com/article/865649211/Kennecott-laying-off-200-workers.html|url-status=dead|archive-date=March 4, 2016|title=Kennecott laying off 200 workers|last=Lee|first=Jasen|website=DeseretNews.com|date=3 March 2016|access-date=6 March 2016}}

The two 8km x 2km rectangular east-west aligned Baray Lakes east and west of Angkor Wat have been created in the 11th century. They are visible with the bare eye from the 410km altitude of the ISS.

File:ISS070-E-071793.jpg

{{See also|List of common misconceptions#Astronomy and spaceflight}}

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.{{cite magazine |last=Hvistendahl |first=Mara |date=February 21, 2008 |title=Is China's Great Wall Visible from Space? |url=http://www.scientificamerican.com/article.cfm?id=is-chinas-great-wall-visible-from-space |magazine=Scientific American |quote=[T]he wall is only visible from low orbit under a specific set of weather and lighting conditions. And many other structures that are less spectacular from an earthly vantage point—desert roads, for example—appear more prominent from an orbital perspective. |accessdate=2024-08-14}}

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,The Family Memoirs of the Rev. William Stukeley (1887) Vol. 3, p. 142. (1754) "Chinese wall, which makes a considerable figure upon the terrestrial globe, and may be discerned at the moon." and Henry Norman made the same claim in 1895.Norman, Henry, The Peoples and Politics of the Far East, p. 215. (1895) "Besides its age it enjoys the reputation of being the only work of human hands on the globe visible from the moon." 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."[http://www.great-wall-china.cn/great-wall-faq/great-wall-of-china-from-space.html How is Great Wall of China from Space?]" A viewer would need visual acuity 17 000 times better than the norm to see the Great Wall from the Moon.{{cite journal | title=Is it Really Possible to See the Great Wall of China from Space with a Naked Eye? | author=Norberto López-Gil | journal=Journal of Optometry | year=2008 | volume=1 | issue=1 | pages=3–4 | url=http://www.journalofoptometry.org/Archive/vol1/pdf/02%20Vol1-n1%20Letter%20to%20the%20Editor.pdf | doi=10.3921/joptom.2008.3 | url-status=dead | archive-url=https://web.archive.org/web/20091007224439/http://www.journalofoptometry.org/Archive/vol1/pdf/02%20Vol1-n1%20Letter%20to%20the%20Editor.pdf | archive-date=7 October 2009 | pmc=3972694 }}

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.[http://www.jpl.nasa.gov/news/news.php?feature=5401 JPL, April 18, 1996, Space Radar Reveals Ancient Segments of China's Great Wall]

The human naked eye has an angular resolution of approximately 280 microradiansMiller, David; Schor, Paulo; Peter Magnante. "Optics of the Normal Eye", pg. 54 of Ophthalmology by Yanoff, Myron; Duker, Jay S. {{ISBN|978-0-323-04332-8}} (μrad) (approx 0.016° or 1 minute of arc), and the ISS targets an altitude of 400 km.{{Cite web|url=https://www.nasa.gov/mission_pages/station/expeditions/expedition26/iss_altitude.html|title=NASA - Higher Altitude Improves Station's Fuel Economy|website=www.nasa.gov|language=en|access-date=20 May 2019}} Using basic trigonometric relations, this means that an astronaut on the ISS with 20/20 vision could potentially detect objects that are 112 m or greater in all dimensions. However, since this would be at the absolute limit of the resolution, objects on the order of 100 m would appear as unidentifiable specks, if not rendered invisible due to other factors, such as atmospheric conditions or poor contrast. For readability of text from the ISS, using the same trigonometric principles and a recommended character size of about 18 arcminutes,{{Cite web|url=https://www.hf.faa.gov/webtraining/visualdisplays/text/size1a.htm|title=Text Size|website=www.hf.faa.gov|access-date=20 May 2019|archive-url=https://web.archive.org/web/20181127163003/http://www.hf.faa.gov/webtraining/visualdisplays/text/size1a.htm|archive-date=27 November 2018}} or about 5,000 μrad, each letter would need to be about {{cvt|2.016|km|mi|1|adj=ri0}} in size for clear legibility in good conditions.

• First images of Earth from space
• Naked-eye planets
• Deck the Halls, a 2006 film that features a man who attempts to get his Christmas lights display visible from space

• [https://eol.jsc.nasa.gov/ Gateway to Astronaut Photography of Earth]

Category:Urban legends

Category:Megastructures

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