This has probably been done before… but not since search was available. My apologies if it’s a chestnut.
A number of questions about what one would actually see as one approaches space:
How high above sea level does the sky turn black during the daytime?
Can any commonly used aircraft fly comfortably (normal engine power, enough lift from wings to stay there) at that altitude?
What happens while approaching that point? I’d guess that a circle of black gradually enlarges from the zenith until, at a certain altitude, it appears to reach the ground.
All stuff you’d think you could just find without asking anybody, but so far no luck.
I’m not sure what altitude you’d have to reach before the sky turns black, but I do know, from geeking out on a bunch of photographs, that the sky at around 70,000 feet is really deep purple, and at 100,000 feet is almost entirely black. Now, there’re very few aircraft that can reach that altitude without difficultuy, and none are in particularly common use. Most of them are reconnaissance planes and high-performance fighter jets. Not your typical Southwest Airlines 737.
Even in an everyday commercial flight at 35 or 40,000 feet, if you look up through the window, you can see that the sky isn’t as bright blue as when you’re on the ground. I don’t know when exactly it’s pitch black, though.
This picture was taken at about 3 pm on a bright sun-lit day, near the middle of summer, less than 10 metres above sea-level. I suspect that the colour of the sky can be deceptive in photographs, since the sky did not look nearly black to me at the time.
From a Lear jet at 55,000 feet it’s quite dark, but I wouldn’t say black. Contrails of commercial jets flying about 25,000 lower are dark gray, not white as viewed from the ground.
The OP is about 13 years old now; hopefully they’ve found their answers somewhere, but just in case…
It’s hard to define an altitude where the sky “turns” black. It’s not like you flip a switch, it’s just a gradual transition. Some years ago James May hopped a ride on a U-2, and his video shows that the sky is pretty dark, almost-black, at around 70,000 feet (see at 6:50):
As for “commonly used” aircraft, that also depends on your definition. most fighter jets have a max service ceiling of around 60,000 feet (as did the Concorde). In the early days of the space age, some military fighter jets could “zoom climb” to altitudes where they could not sustain level flight:
The only planes I’m aware of that can sustain level flight at black-sky altitudes are the U-2 (80,000 feet) and the SR-71 (85,000 feet):
The blackbirds are no longer flying, but the dragon ladies are still in service.
As far as what you see during your ascent to black-sky altitude, James May’s U-2 flight seems to show something like what you describe: the ambient blue of the atmosphere recedes to form a tall, fuzzy wall at the horizon. The apparent height of that wall decreases as you climb, and the visual fuzziness of it gets reduced. By the time you get to low earth orbit (far higher than the U-2 flight), that blue wall is just a thin , bright blue tinge on the rim of the earth:
