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The rotation of the earth on its axis
-It is late, Pirate Pete.
Can't you sleep?
Are you cold?
And a bit afraid of the dark, is that it?
It is perfectly normal to be afraid of things that you do not understand.
Do you want me to turn the light on?
When it is nighttime, just say to yourself that it is daytime on the other side of the planet.
Do you know why?
Because the Earth is round like this ball, and the Sun, like this lamp, can only light up one side at a time.
Can you see the side where it is daytime?
Great, and the side where it is nighttime?
Now, imagine that you could walk on this ball.
It is a strange planet, do you not think?
On one side, it is always daytime and on the other, nighttime.
Is that what it is like on our planet?
Of course, not.
On Earth, the day always comes after the night.
And you know why?
Brilliant idea, Pirate Pete!
Do you think the Sun orbits the Earth?
That is exactly what Ptolemy thought.
He was one of the cleverest astronomers of Ancient Greece.
He said that the Earth was at the center of the universe, and all the other planets revolved around it.
The Moon was the closest and the Sun was the farthest away.
It was a good idea, but completely wrong, unfortunately.
We had to wait over 1 000 years for a Polish genius, Nicolaus Copernicus, to discover that the Earth was not the center of the universe, that the Sun was a star and that the planets revolved around it.
And he based this discovery on a new and revolutionary idea.
Yes, when you look at it from the Sun's position, it is obvious.
The Earth is spinning.
It is spinning around an imaginary line that runs through its center.
This axis is not straight.
It is tilted at an angle.
We call this the Earth's rotation, which causes the succession of day and night.
Now, you know that the Earth is rotating.
The Sun is coming up.