At what altitude can you start seeing the curvature of the Earth? Is it visible from the top of a skyscraper, a mountain peak, or a passenger plane? Can a high-altitude balloon provide a clear view, or is it something you can only witness from space?
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 standing on a mountain peak or flying in a passenger plane. However, even at these heights, we’re just skimming the surface of our planet. For perspective, commercial aircraft typically fly between 31,000 and 38,000 feet (about 5.9 to 7.2 miles) high, which is higher than even Mount Everest, the tallest mountain on Earth.
So, how high do you have to be to see the curvature of the Earth?
Key Takeaways:
- The curvature of the Earth (actually the curvature of the Earth’s horizon) becomes visually discernible from an altitude of around 35,000 feet (10,600 meters), assuming clear conditions and a wide field of view.
- Ancient civilizations inferred Earth’s curvature through observations like disappearing ships on the horizon. Contrary to common misconception, educated people in ancient times did not believe the Earth was flat.
- You can’t see the curvature of the Earth from a homemade rocket. The Earth’s massive size makes its curvature difficult to observe at lower altitudes.
What Do You Mean by the “Curvature of the Earth”?
You can observe the curvature of the Earth even at sea level. The ancient Greeks knew the Earth was round: a ship moving toward the viewer on the horizon will gradually appear with the masts first, followed by the superstructure, and finally the hull.
From just 3 meters (10 feet) above the surface, you can see the horizon 6.2 km (3.85 miles) away. If you’re 30 meters (100 feet) high, you’ll be able to see up to 20 km (12.5 miles) away. This is one of the reasons ancient civilizations understood that the Earth was curved, not flat, as early as the sixth century BC.
Look at the photos below: these three photos vividly illustrate the curvature of the Earth. In the first photo, taken from Old Fort Niagara in Youngstown, NY, across Lake Ontario to Toronto, Canada, only the tops of the buildings are visible, with their bottoms hidden below the horizon 37 miles [60 km] away.
Similarly, the second photo shows the barely visible top of the Boston skyline from Cape Cod, a phenomenon also due to Earth’s curvature.
The third image of Thorntonbank Wind Farm near the Belgian coast demonstrates this curvature even more clearly, as the lower parts of the distant towers are increasingly obscured by the horizon. These observations occur because the Earth’s surface curves away from the observer, gradually concealing the lower parts of objects at a distance.
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 the curvature of the horizon), though, but that would prove nothing. Earth is big.
So, at what altitude can you start seeing the curvature of the Earth?
There’s 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.
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?” 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
Note: I also published this content on my blog.
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- What Is Max-Q and Why Is It Important During Rocket Launches? - January 16, 2025
- Top 10 Tallest Rockets Ever Launched [2025 Update] - January 16, 2025
13 replies on “How High One Must Be to See the Curvature of the Earth?”
Bedford Level Experiment debunks Mystery religion nonsense.
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 ???
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.
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.
Excellent! Short, sweet and to the point. Thanks.
My guess would be really high, because I am high all day, and I’ve never seen it with my own eyes.
Cut out smoking that stuff, Michael!
While in Air Force I have flown on B52s at over 48,000 feet, curvature was very visible from the cockpit.
Thanks for the comment, Marty! It must be an amazing experience, flying at 48,000 feet…
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.
Hi Brandon,
Thanks for the comment. I think you’re right. When I look at the Black Sea on a sunny day (under ideal viewing conditions), even when I am 5-6 meters high from sea level, I think I can always see the curvature of the horizon – albeit vaguely. But I always doubt if I really can see it, or my mind is playing a trick. On an airplane, without a doubt, the curvature is there.
If you have a TI Calculator, you can use the graphing function to ‘zoom in on a curve’ and show it’s flat (ground level) then zoom out to reveal the curve. I understand the argument Flat Earthers have, and it’s very interesting, but if you accept the physics that created the flying jet, and that is indisputable, as we know they exist and can fly on one, then accordingly, one should accept the mathematics that created it. I would like the discussion about how the curvature of earth is ‘disproved’ by long-distance photography addressed though, as that seems to be quite a controversial topic. Also, where the hell are those thousands of ‘lost tapes’ NASA seemed to misplace from the moon landings? If you trust the US Government at this point, you are an idiot, and that is glaringly obvious to anyone with an IQ over room temperature.
INTERESTING!