7

Is the Great Wall of China visible from space?

This is quoted every now and then in film and television (e.g. The Truman Show), purportedly placing it among a rare class of single object that are both man-made and visible from space.

ANNOUNCER: Coming to you now from Seahaven island, enclosed in the largest studio ever constructed, and along with the Great Wall of China, one of only two man-made structures visible from space, now in it's thirtieth great year, it's The Truman Show!

Is this descriptor true, or been true previously? If true, is it the only such that qualifies?

  • 8
    This has been addressed so often, the simplest Google search gives dozens and dozens of articles explaining it. I can't see much we could add that would make the Internet a better place. – Oddthinking Sep 1 at 17:12
  • 3
    @DanielRHicks: The FAQ recommends checking yourself before commenting about notability. There is no doubt that this is a notable claim. – Oddthinking Sep 2 at 5:41
  • 4
    The USA 224 spy satellite has a resolution of 10 cm so anything larger than 10x10 cm will be visible from space. forbes.com/sites/jonathanocallaghan/2019/09/01/… – liftarn Sep 2 at 7:37
  • 1
    With the naked eye, you can barely see it while flying over it in a regular airplane. – Janus Bahs Jacquet Sep 2 at 8:10
  • 2
    Note that The Truman Show is quite an old movie. They just wanted a cool reference, and people believed the claim which was based on basically the Chinese saying "Our Great Wall is the only thing visible from space!". – Luaan Sep 2 at 9:04
19

"Space" and "visible" are poorly defined, but the broad question has been widely addressed already.

Can you see it from the Moon, with a naked eye?

No:

  • NASA

    "The only thing you can see from the Moon is a beautiful sphere, mostly white, some blue and patches of yellow, and every once in a while some green vegetation," said Alan Bean, Apollo 12 astronaut. "No man-made object is visible at this scale."

  • Universe Today

  • Ripley's

  • Livescience

  • Snopes

The moon is about 360,000 km away.

Can you see it from the International Space Station (ISS), with a naked eye?

No:

  • Universe Today

    “The Great Wall of China is not visible from orbit with the naked eye,” Hadfield said via Twitter. “It’s too narrow, and it follows the natural contours and colours [of the landscape].”

  • Ripley's

  • Live Science

  • GBTimes

The ISS is about 400 km away.

Can you see it from low earth orbit, with a naked eye?

It is very difficult:

  • NASA

    Expedition 10 photo showing Great Wall of China The visible wall theory was shaken after China's own astronaut, Yang Liwei, said he couldn’t see the historic structure.

  • Scientific American

    The unglamorous truth is that the 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.

    [...]

    "I have spent a lot of time looking at the Earth from space, including numerous flights over China, and I never saw the wall," asserts former NASA astronaut Jeffrey Hoffman, who flew on five space shuttle missions from 1985 to 1996. "The problem is that the human eye is most sensitive to contrast, and the color of the wall is not that different from the ground on either side of it."

    [...]

    Some U.S. astronauts, notably Eugene Cernan and Ed Lu, have said they've seen the wall from low orbit. But it tends to show up only in certain lighting conditions. When the sun is low on the horizon, for example, the wall casts extended shadows that make it possible to discern its silhouette.

  • Universe Today

  • Live Science

Low Earth Orbit is a broad range, anything below around 2,000 km away. It includes the ISS orbit. So this has limited meaning.

Can you see it from ISS, with a telephoto lens?

Yes, with difficulty:

  • NASA

  • Scientific American

    In 2004 American astronaut Leroy Chiao snapped a photo from the International Space Station of a swath of Inner Mongolia, around 200 miles (320 kilometers) north of Beijing, while the sun's angle was favorable. NASA experts later confirmed that the photo appears to show the wall. But Chiao admitted that he wasn't sure what he was seeing from space.

  • Ripley's

  • Live Science

  • GBTimes

  • CNet

  • 1
    Very nice collection! – DevSolar Sep 2 at 6:53
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    Conclusion: we need to paint the entire Great Wall a vivid shade of hot pink. – Janus Bahs Jacquet Sep 2 at 8:10
  • 1
    @JanusBahsJacquet: Which assumes the Great Wall is "entire" - another myth. – Oddthinking Sep 2 at 14:24
  • 1
    @Oddthinking Well, I meant the entirety of what we have available as the Great Wall. The unfinished or crumbled parts obviously won’t be so easy to pinkify. – Janus Bahs Jacquet Sep 2 at 14:32
6

"Next to impossible with the naked eye"

great wall from space

Source:Space in Images

DETAILS
Title Great Wall of China
Released 22/06/2018 11:00 am
Copyright ESA
Description
ESA astronaut Alexander Gerst took this photo from the Cupola on the International Space Station on 19 June 2018. Gerst posted the image on social media with the comment: "I think I finally found the answer to a question I've been asked a 1000 times. "Can we see the Great Wall of China from the ISS?" Next to impossible with the naked eye. But I tried with an 800 mm tele lens. Still tough to spot. What do you think, is this it?"

Alexander Gerst is currently on his second mission to the International Space Station for Expeditions 56 and 57. The mission is part of ESA’s vision to use Earth-orbiting spacecraft as a place to live and work for the benefit of European society while using the experience to prepare for future voyages of exploration further into the Solar System.

  • The wall is the grey curve roughly from the bottom middle to the right-middle if I'm not mistaken. Indeed many (nearby) roads are far more visible. – Fizz Sep 20 at 21:20

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