The Curvature Fitting Game

The amount of curvature that appears in a photograph of a sphere depends on 1. The radius of the sphere, 2. Camera distance from the sphere, 3. Field of view of the camera, and 4. The distortion characteristic of the camera being used.

The ‘curvature fitting game’ has been flat-Earthers’ favorite pastime. They would try to fit a photograph of Earth’s curvature with another. If they find the result is not proportionally correct, they will make fun of it. They are wrong. Two different photos of a sphere can be taken differently and would show a different curve, even if the object being photographed is the same object.

Continue reading “The Curvature Fitting Game”

The Reasons Why Fisheye Lenses Are Used

Action cameras are being used in high-altitude balloons, rocket launches, and the ISS because they have some advantages compared to other cameras. And most action cameras are equipped with a fisheye lens.

Flat-Earthers allege that there is an evil intention behind every use of fisheye lenses, especially in space and high-altitude usages. They are wrong. The use of fisheye lenses is not unreasonable. And if a rectilinear result is desired, it is trivial to convert any fisheye footage to a rectilinear one.

Continue reading “The Reasons Why Fisheye Lenses Are Used”

Curvature of the Horizon in High-Altitude Balloon Footage

High-altitude balloon footage is often abused by flat-Earthers to show us that the Earth is flat when seen from a high altitude.

We analyzed more than two dozens of footage taken from high-altitude balloons on YouTube, and we can easily conclude the curvature is there and usually easy to spot, including in the cases where flat-Earthers use the video as ‘proof’ of a flat Earth.

Continue reading “Curvature of the Horizon in High-Altitude Balloon Footage”

Little Piggy Balloon Footage: Not An Evidence of A Flat-Earth, Not Even Close

Little Piggy is the nickname of a helium balloon launched by IndianaCaver. It reached the altitude of almost 37 km, before it finally ruptured and fell to the Earth. Before that, it took several hours of video, and IndianaCaver made these video available on YouTube.

Then, some flat-Earthers cherry picked bits of video where the horizon looks flat and presented it as ‘proof’ of flat-Earth. These are widely circulated in various memes and forms, even years after the originals were published.

But, can we really use these videos as ‘proof’ of flat-Earth?

Continue reading “Little Piggy Balloon Footage: Not An Evidence of A Flat-Earth, Not Even Close”

Fisheye Lenses and Earth Curvature

A good majority of pictures of Earth taken from space are being dismissed by flat earthers simply because they are taken using fish-eye lenses. They believe any curvature of Earth shown in these picture are caused by fish-eye effect, and thus, cannot be used as evidence of Earth curvature. They even take a step further: any picture showing curvature of Earth must have been taken by a fish-eye lens.

These claims are, of course, ungrounded. In some cases, we can conclude the curvature is there, even when a fish-eye lens is being used. We can use this useful property of any photographic lens:

A straight line will appear straight as long as it crosses the center point of the image.

Continue reading “Fisheye Lenses and Earth Curvature”