Welcome to part 2 of our ongoing effort to stamp out the scourge of flat-Earthery. Is that a word? Well it is now. Nice. Click here for part 1. Let’s jump right in:

PART II.  MATH AND SCIENCE ARE HARD SOMETIMES

6) Some dude took a level on a plane to prove the Earth was flat.

Sooooo….. wow. This guy brought what looks like a 2 foot level on a plane and recorded it on his phone for over 20 minutes (presumably until the flight attendant yelled at him or his phone ran out of battery). Our flat Earther said that since the level read as “level” the entire time, this means that the plane’s flight wasn’t accounting for the curvature of the Earth. This proves nothing, and here’s why:

Over the course of 1 foot, the curvature of the Earth would change by less then 30 millionth of an inch. You cannot detect this with a level you bought at Home Depot. If you had a 1000 foot long level, you would still need to detect less than 3 hundredths of an inch difference. Do you have any idea how hard it would be to manufacture a level that is 1000 feet long AND is so precisely straight AND strong enough that it doesn’t bow under its own weight that could detect such a small curvature? I am not an engineer, so I have no idea, but I am certain it would be the most expensive level in the history of mankind. As near as I can tell, no one has even tried.

Our friend is also assuming that planes only move forward when they fly.  This is not true – it’s not even remotely close to true. For example, as a plane lands, the pilot keeps the nose up so the rear landing gear hits first.  If you put a level on the floor of the plane during landing, it will tell you the plane is pointing up, but it is clearly descending. I think you get the point – the angle of the cabin of the plane does not necessarily tell you about the direction it is traveling.

There are other reasons this makes no sense, but we at UYBFS will take the high road and not pile on to the trashing this poor fellow is taking on online.  We’ll just say that the only thing he proved is the need for better science education in this country.

7) The Star Trail Proof. When you take pictures of the night sky, all the movement of the stars can be explained by the rotation of the Earth, so why wouldn’t the stars move as the Earth moves? The “trails” would smudge if the Earth was moving so fast around the sun.

OK, space is big – really big – and because the size of space is so hard to comprehend, people sometimes make mistakes. Whether this “proof” is a mathematical mistake or just a lazy assumption, I cannot say, but it’s easily disproved with actual correct math. We can calculate how much apparent movement (as captured by the camera on Earth) the distant stars would experience as the Earth moves around the sun. If you left the aperture of your camera open for 6 hours (way longer than most star trail photos) the Earth would travel over 600,000 km. That’s a lot! However, the nearest star (Alpha Centauri) is over 40 trillion km away. Because of this, the difference in the position of this, the closest star in the photo, would be less then 100th of a pixel width on your fancy new digital SLR. It would take almost a month for the movement to be greater than 1 pixel, and of course you can’t take a star trail picture that long unless you are standing near a pole during winter – because the sun would come up and overexpose the entire picture.

8) The fall off the bottom proof. If the Earth were round, the people in the southern hemisphere would fall off.

Here’s another example of flat Earth and gravity not playing nice.  I will also say, for the record, that this “proof” makes me sadder than all the others, because the total lack of understanding of gravity required to believe this is… well, it’s just so sad. We covered gravity when we discussed the water proof (see part 1, proof number 2). Since the Earth is so massive, it’s gravitational pull keeps all of us – along with animals, rocks, buildings, the atmosphere, and everything else on the Earth that has mass – on the ground. There is no “bottom” or “top” to the Earth in the sense that you & I experience – bottom is always down towards the center of the Earth – the direction gravity pulls us. The version of the globe we all see online and in textbooks shows the north pole at the top, but this is a fabrication – there is no “top” to the Earth in the cosmic sense, because there is no “top” or “bottom” of our solar system or universe to compare it to. If the Chinese inventors who developed the compass had lived in the southern hemisphere instead of the northern one, we would probably think of north as down. In actuality, the Earth’s magnetic field reverses from time to time,so it was just happenstance that human civilization developed to the point of recognizing the polarity of the Earth during a time in which compasses pointed north anyway.

Gravity is real. It is nothing short of madness that I should have to make such a statement over 45 years after we used our knowledge of gravity to slingshot people to the frickin’ moon. But here we are. Gravity is the reason we can stand on the Earth without falling off, it keeps our atmosphere here so we can breathe, it keeps the moon close and drives tides, it keeps us near our sun so we don’t all freeze to death, and it pushes down on our planes forcing them to burn more fuel to keep themselves in the air. It’s also the reason it’s easier to walk downhill than uphill and why is hurts when you fall. Though it is the weakest of the four fundamental forces, on the scale that you & I see, it is the most influential and easily observable force – just drop something and watch it fall. There are no other theories with even the slightest scientific credibility.  To be clear – any suggestion that gravity is not real is a baseless, fabricated, conspiracy-laden claim.

9) The Lighthouse Proof.  If you look up how far light from almost all the lighthouses in the word can be seen, the distances are far greater than would be possible if the earth was curved.  

This is an interesting one, because while many of the calculations performed by the flat Earthers are wrong, the general conclusion that most lighthouses list the distance their lights can be seen as farther than would actually be possible if the Earth was a sphere is true. So what gives? In this case, a few minutes of legwork on the internet yields the result – the distance given is a measure of the brightness of the light rather than the true distance that the light, when installed on top of the lighthouse, can be seen. I know, it sounds confusing, but there is a reason it is done this way: the lights on lighthouses need to be strong enough to see beyond the horizon, because of fog, which reduces the distance light can travel. The distances given in these references are not meant to tell you how far away from a lighthouse you will actually see it’s light, just how strong the light is. So some flat Earther looked up these numbers and immediately accepted/distributed this as “proof” the Earth is flat. It is not. In practical terms, you can estimate how far you can see on a clear day by multiplying the square root of the height of the observers eye above sea level by 1.32 miles (this number takes into account the curvature of the Earth and refraction – the bending of light by our atmosphere, explained in excruciating detail here). So if you are swimming in the ocean with your eye right at sea level, you could see a 100 foot lighthouse 13 miles away from you. Based on this, you could never see most lighthouses beyond 20 miles, which contradicts the published distance for many lighthouses referenced by flat Earthers.

But wait!  It gets more complicated than that! You’ll see farther if you get to a higher vantage point on a boat.  On a large modern cargo ship, you could easily be 200 feet above the water in the bridge (where the captain helms the ship), and even higher if the ship is empty, and thus floating higher in the water.  In this case, you could see that 100 foot lighthouse from over 30 miles away. If you were looking at the Statue of Liberty (which is over 300 feet tall) from that container ship?  You could see that light from over 40 miles away.

So in the end this proves nothing other than math can be tricky. If someone tells you you shouldn’t be able to see a lighthouse from that far out – remind them that this is not a calculation you can do without knowing how high the observer will be on the ship in question. If they persist, just ask them to sail out into the open ocean to test out their theory for his/herself. They probably won’t, but if they do, they’ll prove themselves wrong.

10) The Vantage Point Proof. If the Earth were round, you wouldn’t be able to see things in the distance, or see as far as we can because of the curvature of the Earth. There is a famous rapper who believes this!

This is really the same as the lighthouse proof but less fun because it has no water and boats. Flat-Earthers assume that the curvature of the Earth is a disadvantage with regards to seeing far, since things would get lost behind the horizon, but it’s actually an advantage, and here’s why:

Everyone knows that as you climb higher you get a better view. This would be true for a flat or round Earth so long as there isn’t something higher than you blocking your view. Most people assume we see more from higher up because we are climbing above the tall obstacles in our way. However, on our round Earth, climbing higher brings the added benefit of changing your line of sight in such a way that your horizon moves back further – the horizon you see at 5 feet above sea level is not the same as the horizon you see at 1000 feet above sea level.  This would not be true for a flat Earth, where the only advantage of climbing higher is to see over taller things in front of you.  Here’s a cartoon of how it works:

Click here for part 3 of UYBFS’s flat earth series.

Got a flat Earth proof you’d like debunked?  Add to the comments below.