At what altitude can you start seeing the curvature of the Earth? Can you see it, for example, on top of a skyscraper? Or atop a mountain? Or from a passenger plane? From a high-altitude balloon? From space only?

Most people don’t realize how large the earth is compared to the height of a mountain or the altitude of a passenger aircraft. It’s easy to think we’re really high up when we are atop a high mountain or in a passenger plane, but comparatively, even in the case of the plane (planes fly higher even the highest mountain on Earth – Mount Everest, commercial aircraft typically fly between 31,000 and 38,000 feet – about 5.9 to 7.2 miles – high), we’re just skimming the surface of our planet. So, how high do you have to be to see the curvature of the Earth?

What do you mean by the “curvature of Earth”?

Technically, you can see the curvature of Earth even at sea level. Even the ancient Greeks knew that the Earth is round: a ship on the horizon moving toward the viewer will gradually appear with the masts first, followed by the superstructure, then the hull.

Curvature of the Earth
This image of Thorntonbank Wind Farm (near the Belgian coast) with the lower parts of the more distant towers increasingly hidden by the horizon, demonstrates the curvature of the Earth. By Lieven – Own work, CC BY-SA 4.0, Link

From just 3 meters (10 feet) above the surface, you can see the horizon 6.2 km (3.85 mi) apart. If you’re 30 meters (100 feet) high, you’ll be able to see up to 20 km (12.5 mi) away. This is one of the reasons ancient civilizations understood that the Earth was curved, not flat, at least from the sixth century BC.

So, the real question here is: “at what altitude can you start seeing the curvature of your horizon“.

Spoiler: you have to be a lot higher than that flat-earther ‘Mad’ Mike Hughes who died while trying to reach an altitude of 5,000 feet (1,525 meters) while riding his steam-powered rocket to “prove” the Earth is flat. He could climb a mountain to reach a higher altitude than launching himself onboard his homemade stupid “rocket”. He still wouldn’t see the curvature of Earth (actually curvature of the horizon), though, but that would prove nothing. Earth is big.

How high do you have to be to see the curvature of Earth? Earth from a weather balloon
How high do you have to be to see the curvature of the Earth?

The curvature of the Earth: at what altitude can you start seeing it?

There’s actually a study answering this question titled “Visually discerning the curvature of the Earth” and here’s the abstract of the study:

“Reports and photographs claiming that visual observers can detect the curvature of the Earth from high mountains or high-flying commercial aircraft are investigated. Visual daytime observations show that the minimum altitude at which curvature of the horizon can be detected is at or slightly below 35,000 feet (10,600 meters – about the cruising altitude of a passenger aircraft), providing that the field of view is wide (60 degrees) and nearly cloud-free.”

Scott Manley also created a video about this.

How high do you have to be to see the curvature of the Earth? Video by Scott Manley.

Manley says: “It’s well understood that from the surface of the Earth the curvature of the planet is not readily visible, but, as you travel higher the shape of the world becomes apparent to a casual glance.”

“So I wanted to actually quantify this in a visual form using YouTube’s 360° Video feature, it’s obviously best experienced through a VR headset or a ‘Cardboard’ style viewer, but you can also use the web browser if you just want to appreciate the visuals.”

Sources and further readings

  • “How high must one be for the curvature of the earth to be visible to the eye?” on Stack Exchange
  • At what altitude do you see the curvature of the Earth? on Quora
  • Study: “Visually discerning the curvature of the Earth” on Research Gate
M. Özgür Nevres

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  1. Özgür Nevres

8 Comments

    1. I Was On A Plane From mpls To Chicago And The Bend was Clearly Visible Can Not Flat Earth People Afford 59 $ For A plane Ticket ???

      1. Good point. I think they never left their home. That flat earther who made a homemade rocket to reach an altitude of 5,000 feet should buy a plane ticket, instead, or even climb a mountain.

      2. Funny how when looking out of a plane window before you take of things already start to curve at the edge of the window. And if they dont they wont at any part of the flight. Interesting.

  1. My guess would be really high, because I am high all day, and I’ve never seen it with my own eyes.

  2. While in Air Force I have flown on B52s at over 48,000 feet, curvature was very visible from the cockpit.

  3. I believe this is simply not true – nor is that pub med article true. A pair of eyes are a pretty incredible system. One does need an unobstructed view and a very wide view at that. But saying one has to be at a certain specific elevation to “detect” something visual is an obvious problem. How could there be a specific point, when humans differ in their acuity in various and unknown ways. Does the Pub Med paper author mean some supposed “average” person? One thought is that, in most situations, where there are likely to be fog, clouds or land obstructions, it can be more difficult because of those factors. The other is that different people can “discern” with different amounts of accuracy. If you are used to making the observation, you can see the curvature at much lower altitudes than most people are saying. For example, overlooking Death Valley, on San Gorgonio, which is roughly 11,500 feet, it is pretty apparent that the Earth is curved. But then again, that’s an ideal viewing condition. (During my hikes there I could visibly, without equipment, notice it a bit lower, at maybe around 10,000 feet, but that point is still very much below thick tree cover so climbing a tree or a boulder was necessary. On the other hand, with surveying tripod, level, some care, one can start to make it out a bit lower. Is it obvious to a person who has a lot of ideas flowing and distracting them from making a careful, long observation? No, probably not. Is it visible at 5000 feet? The chance of someone with that amount of perceptual ability is dubious in my opinion. In an airliner at 35,000 it is VERY obvious, so to say that it just THEN becomes visible is ignoring the common logic that many things in life are relative and gradual – there is no SUDDEN point. So I question the article on Pub Med, and find it a bit suspicious.

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