How to prove to anyone that the earth is round

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

11 arguments, after which there will be no doubts.

We live in amazing times. Most of the celestial bodies of the solar system have been explored by NASA probes, GPS satellites circle over the Earth, ISS crews fly steadily into orbit, and return rockets land on barges in the Atlantic Ocean.

Nevertheless, there is still a whole community of people who believe that the Earth is flat. Reading their statements and comments, you sincerely hope that they are all just trolls.

Here are some simple proofs that our planet is round.

Ships and the skyline

If you visit any port, take a look at the horizon and watch the ships. As the ship moves away, it doesn't just get smaller and smaller. It gradually disappears behind the horizon: first the hull disappears, then the mast. Conversely, approaching ships do not appear on the horizon (as they would if the world were flat), but rather emerge from under the sea.

But ships do not emerge from the waves (with the exception of the "Flying Dutchman" from "Pirates of the Caribbean"). The reason that approaching ships look like they are slowly rising from the horizon is because the Earth is not flat, but round.

Varying constellations

Different constellations are visible from different latitudes. This was noticed by the Greek philosopher Aristotle back in 350 BC. NS. Returning from a trip to Egypt, Aristotle wrote that "in Egypt and Cyprus there are stars that are not visible in the northern regions."

The most prominent examples are the constellations Ursa Major and the Southern Cross. Ursa Major, a scoop-like constellation of seven stars, is always visible at latitudes above 41 ° north latitude. Below 25 ° South latitude, you will not see it.

Meanwhile, the Southern Cross, a small constellation of five stars, you will only discover when you reach 20 ° north latitude. And the farther south you move, the higher the Southern Cross will be above the horizon.

If the world were flat, we could observe the same constellations from anywhere on the planet. But this is not the case.

You can repeat Aristotle's experiment when you travel. Find constellations in the sky with these Android and iOS apps.

Lunar eclipses

Another proof of the sphericity of the Earth, found by Aristotle, is the shape of the earth's shadow on the Moon during an eclipse. In an eclipse, the Earth is between the Moon and the Sun, blocking the Moon from sunlight.

The shape of the shadow from the Earth that falls on the Moon during eclipses is perfectly circular. That is why the moon becomes a crescent moon.

Shadow length

The first to calculate the circumference of the earth was a Greek mathematician named Eratosthenes, who was born in 276 BC. NS. He compared the length of the shadows on the summer solstice in Siena (this Egyptian city today is called Aswan) and located north of Alexandria.

At noon, when the sun was directly over Siena, there were no shadows. In Alexandria, a stick set on the ground cast a shadow. Eratosthenes realized that if he knows the angle of the shadow and the distance between cities, he can calculate the circumference of the globe.

On a flat earth, there would be no difference between the length of the shadows. The position of the sun would be the same everywhere. Only the spherical shape of the planet explains why the position of the Sun is different in two cities at a distance of several hundred kilometers from each other.

Observations from above

Another obvious proof of the sphericity of the Earth: the higher you go, the further you can see. If the Earth were flat, you would have the same view regardless of your elevation. The curvature of the Earth limits our viewing range to about five kilometers.

Travel around the world

The first round the world trip was made by the Spaniard Fernand Magellan. The voyage lasted three years, from 1519 to 1522. To circumnavigate the globe, Magellan took five ships (of which two returned) and 260 crew members (of which 18 returned). Fortunately, in our time, in order to make sure that the Earth is round, it is enough to just buy a plane ticket.

If you've ever traveled by plane, you might have noticed the curvature of the Earth's horizon. It is best seen in flight over the oceans.

According to the article Visually discerning the curvature of the Earth, published in the journal Applied Optics, the Earth's curve becomes visible at an altitude of about 10 kilometers, provided the observer has a view of at least 60 °. There is still less visibility from the window of a passenger airliner.

More clearly, the curvature of the horizon is visible if you take off above 15 kilometers. It is best seen in the photographs from the Concorde, but, unfortunately, this supersonic aircraft has not been flying for a long time. However, high-altitude aviation is being reborn in Virgin Galactic's Space Ship Two, a passenger rocket plane. So in the near future we will see new photographs of the Earth taken in suborbital flight.

The plane may well fly around the globe without stopping. Travel around the world by airplane has been carried out several times. At the same time, the planes did not detect any "edges" of the Earth.

Observations from a weather balloon

Ordinary passenger airliners do not fly so high: at an altitude of 8-10 kilometers. Weather balloons rise much higher.

In January 2017, students at the University of Leicester strapped several cameras to a hot air balloon and launched it into the sky. It rose to a height of 23.6 kilometers above the surface, much higher than passenger airliners fly. In the pictures taken by the cameras, the horizon curve is clearly visible.

Shape of other planets

Our planet is pretty ordinary. Of course, there is life on it, but otherwise it does not differ from many other planets.

All our observations show that the planets are spherical. Since we have no good reason to think otherwise, our planet is also spherical.

A flat planet (ours or any other) would be an incredible discovery that would contradict everything we know about planet formation and orbital mechanics.

Time Zones

When it is seven in the evening in Moscow, it is noon in New York, and midnight in Beijing. In Australia, at the same time, 1:30 am. You can see what time it is anywhere in the world, and make sure that the time of day is different everywhere.

There is only one explanation for this: the Earth is round and rotates on its axis. On the side of the planet where the sun is shining, at the moment it is day. The opposite side of the Earth is dark, and there is night. This forces us to use time zones.

Even if we imagine that the Sun is a directional searchlight that runs over a flat Earth, then we would not have a clear day and night. We would still observe the Sun, even being in the shadows, as we can see spotlights shining on the stage in the theater, while being in a dark hall. The only explanation for the change in the time of day is the sphericity of the Earth.

The center of gravity

It is known that gravity always pulls everything towards the center of mass.

Our Earth is spherical. The center of mass of the sphere is, which is logical, in its center. Gravity pulls all objects on the surface towards the Earth's core (that is, straight down) regardless of their location, which we always see.

If we imagine that the Earth is flat, then gravity will have to attract everything on the surface to the center of the plane. That is, if you find yourself at the edge of a flat Earth, gravity will pull you not down, but towards the center of the disk. It is hardly possible to find a place on the planet where things do not fall down, but sideways.

Images from space

The first photograph of the Earth from space was taken in 1946. Since then, we have launched many satellites, probes and astronauts (or astronauts, or taikonauts, depending on the country) there. Some satellites and probes have returned, some remain in Earth orbit or fly through the solar system. And in all the photos and videos transmitted by spacecraft, the Earth is round.

The curvature of the Earth is clearly visible in photographs from the ISS. In addition, you can see photographs of the Earth, which are taken every 10 minutes by the satellite of the Japanese Meteorological Agency "Himawari-8". It is constantly in geostationary orbit. Or here are real-time photos from the DSCOVR satellite, NASA.

Now, if you suddenly find yourself in a flat-earth society, you will have several arguments in an argument with them.