We want to know from children what questions they are worried about. We answer one every week. This question comes from Yara, 4 years old.
In the middle, at the equator, the Earth is a little wider than at the poles. Photo: imago
If you look at photographs of the Earth or a globe, the Earth appears round. It is a sphere that orbits the sun like the other planets. But why is it like this?
It's because of gravity. This is the same force that causes an apple to fall to the ground when you drop it. When the Earth formed, there was only dust and rocks around the sun. Gravity attracted the largest pieces of rock to each other and little by little the earth was formed..
The pressure on the pieces was so great that they heated up and turned into liquid. This liquid material could spread easily and gravity caused it to become a sphere: if a piece stuck out somewhere, it was attracted to the rest. Until the surface of the earth was smooth and round.
The ancient Greeks
You may have heard that people in the Middle Ages thought the Earth was flat. But that is not correct. Actually, back then people already knew that the Earth was round.
Even the ancient Greeks, many thousands of years ago, suspected it. For them then it was more difficult than for us today: we can send satellites and people into space and see the Earth from above. Back then they could only look at the sky from the ground.
But the ancient Greeks had a trick that might help you see that the Earth is a sphere: The next time you're by the sea, watch a sailboat heading toward the horizon. At some point, the helmet disappears first. But you will be able to see the candles for much longer. Precisely because the earth is round and not flat.
This text comes from Laborable day. Our left-wing weekly! Every week, wochentaz is about the world as it is and as it could be. A left-wing weekly with a voice, attitude and a special vision of the world. New every Saturday on newsstands and of course by subscription.
500 years ago, a Portuguese ship called “Victoria” sailed around the world. Back then, that took several years. This circumnavigation proved that the Earth is really round.
But wait, it's not completely round. In the middle, at the equator, the Earth is a little wider than at the poles. Like a ball when you take it in your hands and squeeze it lightly from above and below. This is due to centrifugal force. You'll notice it when you ride the chain carousel.
When the carousel spins, the seats float. And you feel like they push you out and you fly away. This also happens with the land. Because it rotates once a day, it is a little bulbous in the middle.