According to D Marble, a proud flat-earther, they have been lying to you all along: the earth is flat. He even went to the trouble of taking a spirit level on a plane to prove that our planet has no curvature.

The man filmed himself during a flight from North Carolina to Seattle. His goal was to prove that the bubble on the spirit level would not move.

According to D Marble, if the bubble didn't move, then that would be absolute proof that the earth is flat. If the bubble moved, however, then that would be proof that we live on a spinning blue marble.

If The Earth Was Curved, Why Didn't The Bubble Move?

The flat-earther reasoned that if the earth was round, the bubble would move as the plane moved.

But if it was flat, then the bubble would stay at the same point, which is precisely what happened.

The guy, who clearly has no idea how the earth's gravitational lines of force are aligned on this or any other planet, came to the quick conclusion that the earth is flat after this experiment.

After the flight, he was very proud of himself. In fact, he shared this update to help convince more people to become into flat-earthers:

"I recorded a 23 minute and 45 seconds time-lapse, which by those measurements means the plane traveled a little over 203 miles (326km). According to curvature math given to explain the globe model, this should have resulted in the compensation of 5 miles (8km) of curvature. As you'll see there was no measurable compensation for curvature."

The YouTube video drew a lot of reactions. A commenter wondered if the guy was even serious.

Another was baffled by the fact that in this day and age, people like him still exist.

Another lamented that there was no laugh reaction on YouTube.

Whatever the case, the hilarious "proofs" by flat earthers that the world is not round continue to emerge and they grow increasingly ridiculous by the day.

Many people at this point just sit back with frustrated resignation without bothering to argue against the obstinate flat-earth theorists.

Several others consider this movement an embarrassing indictment of our education system.