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You can see the borders of North Korea with China and South Korea at night from the ISS since unlike their neighbours, they have almost no light. That got me thinking, which other country borders (of directly adjacent countries with no large bodies of water in between) are visible from space?

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    $\begingroup$ The former inner German border may have been visible at night from orbit. The control strip of this border was illuminated at night by high-intensity floodlights. But luckily this about 30 years ago. $\endgroup$ – Uwe Jan 12 at 21:21
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    $\begingroup$ Your question got me thinking: within the Schengen space*, I've rarely seen a border between two countries while standing directly on it! (*this qualifies the comment as space exploration right?) $\endgroup$ – Pavel Jan 14 at 10:33
  • $\begingroup$ "are visible from space?" Could you clarify that please? As this would also classify a satellite being in low orbit, just for the sake of taking high resolution pictures. And in that case I'd say any. Also, do you ask for capture devices, releasing their pictures to the public sometimes, so we can give reference as existing answers do? Or do you just want to know, from which borders there is actually light reflected into space? $\endgroup$ – Zaibis Jan 16 at 6:46
  • $\begingroup$ @Zaibis: Since there's lots of borders you can't even see from earth, "any" surely isn't right. As for the clarifications: assume visible with naked eye from ISS, or with with a reasonable camera/lens astronauts use on ISS. And I just mean borders that can somehow be seen, be it because the border is lighted at night, has a large (visible) difference in lighting, visible change in vegetation exactly at the border, etc. The top voted answers here already catch the spirit. $\endgroup$ – DarkDust Jan 16 at 8:03
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    $\begingroup$ @Zaibis: It does qualify since you can see it using one of the cameras aboard the ISS. Have a look at some fotos Alexander Gerst took on the ISS to get an idea what resolution is achievable with DSLRs on the ISS. $\endgroup$ – DarkDust Jan 16 at 10:13
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The border between India and Pakistan is one of the most heavily guarded and well-lit borders in the world, so much so that it can be seen from space at night. It covers an immense distance from the Arabian Sea to the Himalayan foothills.

Here is how it looks from ISS. India-Pakistan Border at Night from NASA Earth Observatory

The winding border between Pakistan and India is lit by security lights that have a distinct orange tone. The port city of Karachi is the bright cluster of lights facing the Arabian Sea. For scale, the distance from Karachi to the foothills of the Himalaya Mountains is 1,160 kilometers (720 miles)

Indo-Pak Border

Another interesting historical divide that can be seen even today is the effect of the Berlin wall. Despite the reunification, the remnants can be still seen today. Berlin at Night by ESA astronaut André Kuipers. A zoomed-in version of the original image from the Washington Post is shown below.

The former division between East and West Berlin can be seen. The yellow lights correspond to East Berlin and the greener tones show West Berlin. The difference in colour is due to yellow/orange sodium lamps in erstwhile East Berlin and white-green mercury lamps in West Berlin

Thanks to @winny for pointing out the reason for the difference in the hues.

Berlin at night

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Another border which is visible due to the lack of light is the Haitian border with the Dominican Republic:

Haiti at night

The area highlighted on the left is Haiti, of which only Port Au Prince can be seen at night. The bright island on the right is Puerto Rico.

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    $\begingroup$ And during the day you can tell them appart from the lack of vegetation on the Haitian side. $\endgroup$ – Quentin Hayot Jan 15 at 12:55
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    $\begingroup$ That's a good example. What was the source for this image? $\endgroup$ – Jason R Jan 15 at 14:08
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You did not specify if you are thinking of any border or only an anthropogenic one.

Anthropogenic (they will likely be visible due to different levels of economic development):

  1. Egypt and Israel (different level of development visible on both sides)

  2. Haiti and Dominican Republic (less vegetation in Haiti)

Natural ones (rivers and mountain ranges can be seen from space):

  1. Mexico and USA (Rio Grande)

  2. Germany and France (Rhine)

  3. Germany and Poland (Oder)

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  • $\begingroup$ A part of the Rhine is only a part of the border between Germany and France. $\endgroup$ – Uwe Jan 16 at 11:04
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While LED lighting is taking over (and is likely CW), plenty of outdoor street lights in cities and highways still use high pressure mercury and sodium discharge lamps running on mains AC voltage. They don't rectify and so will produce two pulses per cycle of AC.

Therefore any technique that can chop up time, a rolling shutter effect or simple aliasing in time from a video device, or even a spinning piece of paper with slits on the end of a space-rated paperclip would be able to distinguish a 50Hz country from a 60Hz country.

So Suriname|French Guyana or Argentena+Chile+Uraguay+Paraguay+Boliva|north thereof or Saudi Arabia|Neighbors or perhaps Liberia|Neighbors (needs better data)

For even more fun, just have a look within Japan, Tokyo prefecture and north is 50 Hz, and south of it is 60 Hz!

enter image description here

Source


Two screen shots from the YouTube video 50 Hz vs 60 Hz vs 400 hz A.C. Hum Sound Comparsion converted into GIF:

enter image description here

click/open separately to view full size

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    $\begingroup$ The street lights on the two sides of Cypress are different colors. It’s really visible when flying at night, so perhaps is visible from space too. $\endgroup$ – Bob Jacobsen Jan 13 at 6:38
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    $\begingroup$ @BobJacobsen The island is Cyprus; a cypress is a coniferous tree. $\endgroup$ – David Richerby Jan 13 at 18:13
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    $\begingroup$ @DavidRicherby when capitalized as a proper noun, it's a semiconductor manufacturer $\endgroup$ – uhoh Jan 13 at 22:22
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Most of the answers were concerning night time pictures. Let me add some nice example of day time pictures, of Israel.


enter image description here

Plenty of grazing animals on the Egyptian side of the border, but none on the Israeli side. Gaza is distinct from both, evident by the densely populated areas and small subdivisions of farms. Compare to the larger farms in Israel, and no farms in Egypt (except along the coast).


enter image description here

The Israeli Golan Heights are pretty much empty and most of the area is grassland. On the other hand, the Syrian side of the border has many small villages and roads, and grassland is affected by grazing.


enter image description here

The Yatir Forest in Israel is an artificial planted forest. Naturally, it stops at the border.

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A part of the border between Austria, Switzerland and Germany may be seen from orbit.

For the biggest part of the Lake Constance, the Upper Lake, the location of the borders within the water is not defined. Therefore the lake itself is the border, a very wide one, easily to be seen from orbit at day and night.

Within a smaller part, the Lower Lake, the border within the water is defined.

See Wikipedia for International borders of Lake Constance or this chart of the Bodensee.

Another part of the border between France and Germany is the river Rhein between the towns Basel and Karlsruhe, see this chart.

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The outline of Lesotho can be seen by the distinct mountain texture (80% of the country being above 1800 m) setting it apart from the surrounding South Africa.

enter image description here

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  • $\begingroup$ Is this really true? Or isn't it just a different photography technique? $\endgroup$ – Sebastian Jan 16 at 15:16
  • $\begingroup$ @Sebastian What do you mean by true? I was never in space, I cannot know if the borders of Lesotho are visible from space. This is just a screenshot of google maps and the border is marked, but I think that the mountain texture is visible there. $\endgroup$ – Trilarion Jan 19 at 12:43
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Belgium, sort of:

enter image description here

Belgium has road lighting on almost all of its roads. The neighboring countries don't. The southern Netherlands, the Ruhrgebiet and the Lille area are densely populated so the distinction is less clear here.

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    $\begingroup$ And of course the SE of Belgium would have to be disregarded here as the lighting there is no different from that in neighbouring areas of Germany or France. $\endgroup$ – jwenting Jan 14 at 6:53
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Looking at this high resolution image of the Earth at night, here are a few borders I could find.

US/ Mexico can be partially seen, particularly in the Western US. enter image description here

Guatamala and its southern neighbors of Honduras/ El Salvador enter image description here

India/ Pakistan is VERY noticeable.

enter image description here

North/ South Korea is also VERY obvious.

enter image description here

Italy seems pretty obvious, but it is probably because the northern end of the country isn't very habitable.

enter image description here

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    $\begingroup$ This shows the the extent of the Po Valley rather than the border of Italy. $\endgroup$ – René Nyffenegger Jan 15 at 9:15
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    $\begingroup$ Besides Italy, India/Pakistan was already covered very nicely and North Korea/South Korea was already covered as "obvious" the first sentence of the question. US/Mexico shows a gradient, but if you don't already know where the border is, I don't think there's a clear border line there at all. Same with Guatamala; in this case I am sure I don't know where the border is and I can not see any clear line representing a border. $\endgroup$ – uhoh Jan 15 at 10:14

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