Take all the time that you need to understand this
I took all the time I needed a few years ago to calculate how far can be seen at any given height along with the apparent arc and how far below eye level the horizon line sits. Rather than trusting what anyone else said, I dusted off my high school trigonometry to figure out how this all works.
At 6 feet (tall person) or 30,000 feet (looking out airplane window) the horizon line will be curved too slightly to be seen by a human. You can’t look out an airplane window and confirm with the naked eye that the horizon line is a degree or so below eye level. You would need to travel several miles up into the air before the curvature becomes readily perceptible. Most of us will never get to do that, and are left to our calculators.
The Earth is large enough that we won’t see a curve regardless of whether it is flat or round.
but the slope is steep (do you really know it or are you just repeating what NdGT said? From 30,000 feet, you can see about 200 hundred miles, and the drop over that distance is....26,657.7237 feet thats room for a huge mountain of curvature to notice.
So, yes, it is established that you would notice from 30,000 feet, because you could see a drop off of miles.
Using your own numbers:
If we are 30,000 above sea level looking out 200 miles where the horizon line meets the earth, and the drop-off is 26,657 feet, then the horizon line will be about 3 degrees below eye level.
arcsin(56657 / (200 * 5280)) = 3.257 degrees
Nobody looking out a plane window would be able to say whether the horizon line is at eye level or 3 degrees too low. If I recall the drop-off is actually less than this - I'm simply using the numbers you gave me.
no, you heard this and you repeated it. thats all
Funny how I get this same response regardless of whether I'm speaking to a fellow questioner or anybody else.
Punching in your numbers gives me a little over 6 degrees.
asin(240338 / 2244000) = 6.15 degrees
Again, I'm just plugging your 425 mile and 22 dropoff figures. My own calculations were different than that.
would you notice 13 degrees?
Probably. I might able to recognize 6 degrees or the even the lesser angle I calculated myself a few years ago. I do find it surprising how little the horizon line should drop even at such great heights.
This is exactly the point I'm trying to make. A person would have to travel over 20 miles up before they could even begin to perceive the arc of the Earth.
Think about it differently. you are about 5.5 miles high and are looking out across 200 miles, and there is 5 miles of drop in all directions, dropping slightly at first but getting steeper as you look to the horizon. still saying the same thing, and you are saying you would not notice this and i am saying you would.
From an airplane you wouldn't be able to perceive anything other than a straight line at eye level. If we were standing on a more stable structure which is 6 miles high, then perhaps a level could be used to show that the horizon is slightly lower than straight ahead.
look at this
I clicked around the video, and have watched others like it. The apparently flat horizon is what I would expect to see at that height whether the Earth is flat or round. Consider the calculations we just made. The horizon would be a few degrees below level in all directions, and appear flat. You would need to travel much higher before an arc could be seen.
I took all the time I needed a few years ago to calculate how far can be seen at any given height along with the apparent arc and how far below eye level the horizon line sits. Rather than trusting what anyone else said, I dusted off my high school trigonometry to figure out how this all works.
At 6 feet (tall person) or 30,000 feet (looking out airplane window) the horizon line will be curved too slightly to be seen by a human. You can’t look out an airplane window and confirm with the naked eye that the horizon line is a degree or so below eye level. You would need to travel several miles up into the air before the curvature becomes readily perceptible. Most of us will never get to do that, and are left to our calculators.
The Earth is large enough that we won’t see a curve regardless of whether it is flat or round.
Using your own numbers:
If we are 30,000 above sea level looking out 200 miles where the horizon line meets the earth, and the drop-off is 26,657 feet, then the horizon line will be about 3 degrees below eye level.
arcsin(56657 / (200 * 5280)) = 3.257 degrees
Nobody looking out a plane window would be able to say whether the horizon line is at eye level or 3 degrees too low. If I recall the drop-off is actually less than this - I'm simply using the numbers you gave me.
Funny how I get this same response regardless of whether I'm speaking to a fellow questioner or anybody else.
Punching in your numbers gives me a little over 6 degrees.
asin(240338 / 2244000) = 6.15 degrees
Again, I'm just plugging your 425 mile and 22 dropoff figures. My own calculations were different than that.
Probably. I might able to recognize 6 degrees or the even the lesser angle I calculated myself a few years ago. I do find it surprising how little the horizon line should drop even at such great heights.
This is exactly the point I'm trying to make. A person would have to travel over 20 miles up before they could even begin to perceive the arc of the Earth.
From an airplane you wouldn't be able to perceive anything other than a straight line at eye level. If we were standing on a more stable structure which is 6 miles high, then perhaps a level could be used to show that the horizon is slightly lower than straight ahead.
I clicked around the video, and have watched others like it. The apparently flat horizon is what I would expect to see at that height whether the Earth is flat or round. Consider the calculations we just made. The horizon would be a few degrees below level in all directions, and appear flat. You would need to travel much higher before an arc could be seen.