Whether at sea-level, the top of Mount Everest, or flying over a hundred thousand feet in the air, the always horizontal horizon line always rises up to meet the eye-level of the observer and remains perfectly flat. You can test for yourself on a beach or hilltop, in a large field or desert, aboard a hot-air balloon or helicopter; you will see the panoramic horizon ascend with you and remain completely level all around. If the Earth were actually a big ball, however, the horizon should sink as you ascend, not rise to your eye-level, and it would dip at each end of your periphery, not remain flat all around. Standing in a rising balloon, you would have to look downwards to the horizon; the highest point of the ball-Earth would be directly beneath you and declining on each side.
In an editorial from the London Journal, July 18, 1857, one journalist described quite the opposite in his hot-air balloon ascent, “The chief peculiarity of the view from a balloon at a considerable elevation was the altitude of the horizon, which remained practically on a level with the eye at an elevation of two miles, causing the surface of the earth to appear concave instead of convex, and to recede during the rapid ascent, whilst the horizon and the balloon seemed to be stationary.” J. Glaisher wrote in his, “Travels in the Air,” that “On looking over the top of the car, the horizon appeared to be on a level with the eye, and taking a grand view of the whole visible area beneath, I was struck with its great regularity; all was dwarfed to one plane; it seemed too flat.” M. Victor Emanuel, another hot-air balloonist, wrote that, “Instead of the earth declining from the view on either side, and the higher part being under the car, as is popularly supposed, it was the exact opposite; the lowest part, like a huge basin, being immediately under the car, and the horizon on all sides rising to the level of the eye.” Yet another American hot-air balloonist, Mr. Elliot wrote, “The aeronaut may well be the most skeptical man about the rotundity of the earth. Philosophy forces the truth upon us; but the view of the earth from the elevation of a balloon is that of an immense terrestrial basin, the deeper part of which is directly under one’s feet.” And in Mayhew’s “Great World of London,” one aeronaut recorded that, “Another curious effect of the aerial ascent was, that the Earth, when we were at our greatest altitude, positively appeared concave, looking like a huge dark bowl, rather than the convex sphere such as we naturally expect to see it. The horizon always appears to be on a level with our eye, and seems to rise as we rise, until at length the elevation of the circular boundary line of the sight becomes so marked that the Earth assumes the anomalous appearance as we have said of a concave rather than a convex body.”
Amateurs have sent balloons to heights of over 121,000 feet and you can watch video online of the horizon rising with the camera-level and remaining perfectly flat 360 degrees around. NASA videos and other “official” sources, however, such as the recent Red Bull skydive at 128,000 feet have been caught adding fake curvature to the Earth via wide-angle lenses and post-production work. Panoramic photos atop Mount Everest also often claim to be displaying Earth’s curvature, but this is simply the result of distortions and limitations inherent in wide-angle lenses. I have exposed the full extent of NASA’s camera trickery and doctored CGI sphere Earth pictures/videos here, here and here.
“The camera distorted horizons have always been a misleading factor with those who have not freed their minds from the ‘planet’ or ‘globe earth indoctrination.’ Three or four years ago, the U.S.I.S. booklet ‘Science Horizons,’ carried a note to the effect that the Americans hoped to produce a lens which would NOT distort level horizons. So far I am not aware that such aid to truer photography has yet been made available. Flat Earthists however can prove that due to the known laws of perspective, the horizon, optically rises and remains level with the observer’s, or the camera’s eye, no matter what height is achieved. In fact the earth immediately beneath balloon, airplane, rocket or capsule, presents a dish-shaped or concave appearance. The point of earth immediately below the vehicle is the lowest. It is NOT the highest point of your ‘globe’ earth with the dip or curvature of the ‘ball’ sweeping away downwards to a horizon far away below the eye level.” -Samuel Shenton, “The Plane Truth”
If the Earth were actually a big ball 25,000 miles in circumference, the horizon would be noticeably curved (even at sea-level), and everything on or approaching the horizon would appear to tilt backwards slightly from your perspective. Distant buildings along the horizon would all look like leaning towers of Piza falling away from the observer. A hot-air balloon taking off then drifting steadily away from you, on a ball-Earth would slowly and constantly appear to lean back more and more the farther away it flew, the bottom of the basket coming gradually into view as the top of the balloon disappears from sight. In reality, however, buildings, balloons, trees, people, anything and everything at right angles to the ground/horizon remains so regardless the distance of the observer.
“The marine horizon, from whatever position it is viewed, always appears to be, and is, in fact, a perfectly level line, and since this appearance is the same in all parts of the world, its surface must be level; and therefore the Earth is a Plane. This may be proved to be the case, by erecting at a suitable elevation on the sea shore, a duly-levelled board, or a string – at right angles to a plumb-line – tightly stretched between two vertical poles. On looking towards the sea, the horizontal line for a distance of 20 miles may be easily observed, and throughout its entire length it will be found to coincide with the straight-edge, or string: but if the earth were a globe, the horizontal line would form an arc of twenty miles in length, curveting both ways from the center, at the rate of eight inches, multiplied by the square of the distance. Hence the horizontal line at either end of the distance ought to be depressed some 66 feet below the horizon in the center. But as no such appearance is ever presented, it necessarily follows that the earth cannot be a globe, or other than a plane.” -B. Chas. Brough, “The Zetetic” Volume 1 Number 1, July 1872
Anyone can prove the sea-horizon perfectly straight and the entire Earth perfectly flat using nothing more than a level, tripods and a wooden plank. At any altitude above sea-level, simply fix a 6-12 foot long, smooth, leveled board edgewise upon tripods and observe the skyline from eye-level behind it. The distant horizon will always align perfectly parallel with the upper edge of the board. Furthermore, if you move in a half-circle from one end of the board to the other whilst observing the skyline over the upper edge, you will be able to trace a clear, flat 10-20 miles depending on your altitude. This would be impossible if the Earth were a globe and the surface of water convex! If the Earth were actually a globe 25,000 miles in circumference, the horizon would align over the center of the board but then gradually, noticeably decline towards the extremities. Just ten miles on each side would necessitate an easily visible curvature of 66.6 feet from each end to the center.
“It is known that the horizon at sea, whatever distance it may extend to the right and left of the observer on land, always appears as a straight line. The following experiment has been tried in various parts of the country. At Brighton, on a rising ground near the race course, two poles were fixed in the earth six yards apart, and directly opposite the sea. Between these poles a line was tightly stretched parallel to the horizon. From the center of the line the view embraced not less than 20 miles on each side making a distance of 40 miles. A vessel was observed sailing directly westwards; the line cut the rigging a little above the bulwarks, which it did for several hours or until the vessel had sailed the whole distance of 40 miles. The ship coming into view from the east would have to ascend an inclined plane for 20 miles until it arrived at the center of the arc, whence it would have to descend for the same distance. The square of 20 miles multiplied by 8 inches gives 266 feet as the amount the vessel would be below the line at the beginning and at the end of the 40 miles.” -Dr. Samuel Rowbotham, “Zetetic Astronomy, Earth Not a Globe!” (20)
From the highland near Portsmouth Harbor in Hampshire, England looking across Spithead to the Isle of Wight, the entire base of the island, where water and land come together composes a perfectly straight line 22 statute miles long. According to the ball-Earth theory, the Isle of Wight should decline 80 feet from the center on each side to account for the necessary curvature. The cross-hairs of a good theodolite directed there, however, have repeatedly shown the land and water line to be perfectly level.
On a clear day from the highland near Douglas Harbor on the Isle of Man, the whole length of the coast of North Wales is often plainly visible to the naked eye. From the Point of Ayr at the mouth of the River Dee to Holyhead comprises a 50 mile stretch which has also been repeatedly found to be perfectly horizontal. If the Earth actually had curvature of 8 inches per mile squared, as NASA and modern astronomy claim, the 50 mile length of Welsh coast seen along the horizon in Liverpool Bay would have to decline from the center-point an easily detectable 416 feet on each side!
“But as such declination, or downward curvation, cannot be detected, the conclusion is logically inevitable that it has no existence. Let the reader seriously ask whether any and what reason exists in Nature to prevent the fall of more than 400 feet being visible to the eye, or incapable of detection by any optical or mathematical means whatever. This question is especially important when it is considered that at the same distance, and on the upper outline of the same land, changes of level of only a few yards extent are quickly and unmistakably perceptible. If a man is guided by evidence and reason, and influenced by a love of truth and consistency, he cannot longer maintain that the earth is a globe. He must feel that to do so is to war with the evidence of his senses, to deny that any importance attaches to fact and experiment, to ignore entirely the value of logical process, and to cease to rely upon practical induction.” -Dr. Samuel Rowbotham, “Zetetic Astronomy, Earth Not a Globe!” (28)