Every single day the sky goes light and then dark again, and it is so ordinary that most people never ask why. The answer is not about the Sun at all. It is about the ground you are standing on.
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1. The Earth never stops spinning.
Right now, while you are reading this, the planet under your feet is turning. You cannot feel it because everything around you — the ground, the air, your chair — is turning with you.
2. One spin takes 24 hours.
That is where a day comes from. One full turn of the Earth, and you are back where you started.
3. Daytime is simply the side facing the Sun.
Half of the Earth is always lit up and half is always dark. As the planet turns, your half swings into the light, and that is morning.
4. Night is the side facing away.
Nothing switches off. Your part of the world has just turned away from the Sun, and the Sun is busy shining on somebody else.
5. The Sun does not move across the sky. You do.
It really looks as though the Sun crawls across from one side to the other. It doesn’t. The Earth is turning, and the Sun only appears to move because you are moving past it.
6. Your shadow changes all day for the same reason.
In the morning and evening, when the Sun is low, shadows are long. At midday, when it is high, they are short. Watch a shadow for a day and you are really watching the Earth turn.
7. The Earth spins around an imaginary line.
It is called the axis, and it runs straight through the middle of the planet from the North Pole to the South Pole. Nothing is actually there — it is just the line everything turns around.
8. It is never the same time everywhere.
When you are having breakfast in Britain, somebody in Australia is going to bed. That is why the world is split into time zones.
9. Spinning gives us days. Going round the Sun gives us years.
These are two different journeys. The Earth spins once every 24 hours, and it travels all the way round the Sun once every 365 and a bit days.
10. At the poles, the Sun can stay up for months.
Because the Earth is tilted, the far north and far south get summers where the Sun barely sets and winters where it barely rises. In parts of Norway the Sun does not go down for weeks.
📖 Words to know
- Rotate
- To spin around. The Earth rotates once every 24 hours.
- Axis
- The imaginary line a spinning object turns around. The Earth’s runs from pole to pole.
- Orbit
- The path one object takes around another. The Earth’s orbit goes round the Sun and takes a year.
- Shadow
- The dark shape left where something blocks the light.
⚠️ Watch out!
🎧 Listen and watch
- Will the Earth stop spinning? — what would happen if it ever did.
- Gravity — the force that keeps us all attached while the planet turns.
How much do you know about day and night?
What causes day and night?
- The Earth spinning round
- The Sun moving round the Earth
- The Sun switching off at night
- Clouds covering the Sun
Why does the Sun look like it moves across the sky?
- Because the Earth is turning
- Because the Sun orbits us
- Because the Sun is falling
- Because the Moon pushes it along
What is the Earth's axis?
- The imaginary line it spins around
- A giant metal rod through the middle
- The path it takes round the Sun
- The edge of its shadow
Want more? Try our Top 10 Facts about Earth, The Sun, The Moon and The Solar System.
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