# How far up must you go to recognize outlines of continents? **URL:** \ **Category:** Factual Questions\ **Created:** [October 15, 2010, 11:16pm UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300 "2010-10-15T23:16:17Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![rostfrei](https://avatars.discourse-cdn.com/v4/letter/r/7bcc69/32.png) [@rostfrei](https://boards.straightdope.com/u/rostfrei)\ **Post date:** [October 15, 2010, 11:16pm UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/1 "2010-10-15T23:16:17Z")
The space tourism discussions that I’ve been seeing on the news lately have me wondering… How far up into the sky would one have to go in order to see recognizeable features of the earth, like the outline of Florida, etc. How far up woul you have to go to see more than one continent at a time? Dozens of miles? Hundreds of miles? And is it true that from the Concorde, you could see the curvature of earth? ---
**Author:** ![OldGuy](https://avatars.discourse-cdn.com/v4/letter/o/3bc359/32.png) [@OldGuy](https://boards.straightdope.com/u/OldGuy)\ **Post date:** [October 15, 2010, 11:29pm UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/2 "2010-10-15T23:29:36Z")
You can certainly see any two of Europe, Asia and Africa or North and South America at the same time from a height of essentially 0. I believe you can see Asia and North America at the same time (though certainly not from Palin’s house) ---
**Author:** ![robert\_columbia](https://avatars.discourse-cdn.com/v4/letter/r/e79b87/32.png) [@robert\_columbia](https://boards.straightdope.com/u/robert_columbia)\ **Post date:** [October 15, 2010, 11:33pm UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/3 "2010-10-15T23:33:11Z")
I’ve seen the outline of Lake Michigan clearly when flying into Chicago. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [October 16, 2010, 12:46am UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/4 "2010-10-16T00:46:46Z")
Flying from Europe to the northeastern US takes you over the characteristically scalloped eastern edge of North America, with Nova Scotia and Cape Cod quite obvious and with a little imagination part of the grand curve out to the next big cape, Hatteras. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [October 16, 2010, 1:34am UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/5 "2010-10-16T01:34:02Z")
Well, if the OP means the ability to discern the whole continent as opposed to some recognizable fraction of it (which frankly depends on how well the person viewing can extrapolate a tiny bit into the larger picture) then: According to [this page](http://www.ringbell.co.uk/info/hdist.htm) which calculates distance to the horizon and assuming the US is [3,400 miles wide](http://wiki.answers.com/Q/What_is_furthest_distance_east_to_west_in_the_United_States) at its widest point then to see all of it I get (roughly) 1,900,000 feet (about 360 miles up). For reference the Space Shuttle will [orbit as high as 385 miles](http://www.vibrationdata.com/space/Shuttle.html) up (although often lower…depends on the mission). Of course at lower altitudes the shape of the US is easily discernible but if that calculator above is correct to see the whole US at once the Space Shuttle would need to be close to its maximum altitude. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [October 16, 2010, 1:37am UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/6 "2010-10-16T01:37:26Z")
> [@robert\_andrews](#): > > I’ve seen the outline of Lake Michigan clearly when flying into Chicago. On a clear day I can see enough of the lake from the top of the [John Hancock](http://www.visitingdc.com/city/john-hancock-center-address.asp) to get a good sense of its shape as I have seen it on a map. ---
**Author:** ![matt\_mcl](https://avatars.discourse-cdn.com/v4/letter/m/7ab992/32.png) [@matt\_mcl](https://boards.straightdope.com/u/matt_mcl)\ **Post date:** [October 16, 2010, 1:52am UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/7 "2010-10-16T01:52:21Z")
I can easily see the recognizable shapes of the outline of the Island of Montreal when coming in for a landing at the airport. ---
**Author:** ![Ximenean](https://avatars.discourse-cdn.com/v4/letter/x/aca169/32.png) [@Ximenean](https://boards.straightdope.com/u/Ximenean)\ **Post date:** [October 16, 2010, 2:22pm UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/8 "2010-10-16T14:22:43Z")
I think at typical aeroplane altitudes, atmospheric haze is going to be the limiting factor, the absolute limit being something like 200-250 miles. But that would require exceptional visibility, keen eyesight, and a good knowledge of what you were looking at. I have identified fetaures about 120 miles away from a plane cruising quite high, at 42,000 feet, but at that distance it’s a question of differentiating one shade of blue-grey haze from a slightly different shade. The features I saw were islands, which are a bit easier because the reflections from the surrounding sea help delineate them. Mountain peaks could be identified from considerably further, I should think. ---
**Author:** ![sunstone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunstone/32/3372_2.png) [@sunstone](https://boards.straightdope.com/u/sunstone)\ **Post date:** [October 16, 2010, 8:15pm UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/9 "2010-10-16T20:15:43Z")
Here is a cool way to answer your question: Open Google Earth. Center your view of the earth on the middle of a continent. Zoom all the way in, and then zoom back out slowly…paying attention to the altitude numbers that you can see in the bottom bar. When you can recognize the continent, that is your answer…which will vary with other persons experience. ---
**Author:** ![pmwgreen](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@pmwgreen](https://boards.straightdope.com/u/pmwgreen)\ **Post date:** [October 16, 2010, 9:57pm UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/10 "2010-10-16T21:57:29Z")
It’s possible that once you have gotten far enough away to see the continents, the atmosphere gives you enough haze that you can’t see the outlines. Look at the NASA pictures of Earth taken by Moon bound flights. It’s hard to get anything out of them other than blue and white. ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [October 16, 2010, 10:44pm UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/11 "2010-10-16T22:44:27Z")
If you’re curious about this sort of thing you have to check out the Orbiter Space Flight Simulator. Just Google for those words and you’ll find it. It’s free and it’s fun, although for the purposes of your question it would be better suited to a world without haze or clouds. IRL coastlines tend to be natural generators of atmospheric haze and clouds, so it’s very rare that an astronaut can look down and see all of Florida, or all of Europe. Fly safe. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [October 18, 2010, 8:08am UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/12 "2010-10-18T08:08:41Z")
> [@Whack-a-Mole](#): > > Well, if the OP means the ability to discern the whole continent as opposed to some recognizable fraction of it (which frankly depends on how well the person viewing can extrapolate a tiny bit into the larger picture) then: > > According to [this page](http://www.ringbell.co.uk/info/hdist.htm) which calculates distance to the horizon and assuming the US is [3,400 miles wide](http://wiki.answers.com/Q/What_is_furthest_distance_east_to_west_in_the_United_States) at its widest point then to see all of it I get (roughly) 1,900,000 feet (about 360 miles up). > > For reference the Space Shuttle will [orbit as high as 385 miles](http://www.vibrationdata.com/space/Shuttle.html) up (although often lower…depends on the mission). > > Of course at lower altitudes the shape of the US is easily discernible but if that calculator above is correct to see the whole US at once the Space Shuttle would need to be close to its maximum altitude. Except at that height, there are nearly always clouds in the way that will block your view of part of the continent. ---
**Author:** ![janeslogin](https://avatars.discourse-cdn.com/v4/letter/j/df788c/32.png) [@janeslogin](https://boards.straightdope.com/u/janeslogin)\ **Post date:** [October 18, 2010, 9:44pm UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/13 "2010-10-18T21:44:21Z")
You may be interested in Dish Earth, usually channel 287 on Dishnetwork. Someone you know almost certainly has Dish. It looks like [this](http://blogs.discovermagazine.com/cosmicvariance/files/2009/04/earth1.gif)many days. Someone may know, is this low earth orbit? 2000km? On this channel you can sometimes see the moon and eclipses sometimes make a dark spot not to crisp. ---
**Author:** ![Saltire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saltire/32/553_2.png) [@Saltire](https://boards.straightdope.com/u/Saltire)\ **Post date:** [October 19, 2010, 3:46pm UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/14 "2010-10-19T15:46:09Z")
Dish Earth is a picture from EchoStar XI, which is in geosynchronous orbit 35,786 kilometers (22,236 miles) above the equator. This is far higher than low earth orbit, which is defined as less than 2000 kilometers up. ---
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [October 19, 2010, 10:33pm UTC](https://boards.straightdope.com/t/how-far-up-must-you-go-to-recognize-outlines-of-continents/557300/15 "2010-10-19T22:33:54Z")
> [@rostfrei](#): > > And is it true that from the Concorde, you could see the curvature of earth? I forget the exact figures, but if I recall correctly, normal plane flights do not afford much in the way of viewing the curvature of the Earth. However, at pretty much any altitude, including standing on a beach, the horizon appears curved, such that it will be pretty hard to tell whether the curvature you are seeing at greater heights is the horizon or the actual Earth curvature, unless you can also see a pretty big chunk of the planet.