A spinning Earth story
Why Day Turns Into Night
Earth turns like a slow ball. One side faces the Sun. The other waits.
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Step 1 of 5
The Sun does not turn off.
It shines all the time, in every direction, without pausing. Nothing about the Sun changes when your evening arrives.
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Step 2 of 5
Sunlight can only light up one half.
A ball lit from one side has a bright half and a dark half. Earth is a ball, so half of it is always in daylight and half is always in night.
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Step 3 of 5
Earth spins all the way round each day.
Our planet turns on its axis like a slow top. Where you are standing gets carried from the dark half into the lit half and back again.
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Step 4 of 5
Sunrise is you turning, not the Sun rising.
The Sun looks like it climbs out of the ground in the morning. Really the ground you stand on is rotating forward to face it.
At the equator you are being carried around at about 1,600 km per hour — and you feel nothing, because everything moves with you.
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Step 5 of 5
One full turn is one day.
Earth takes about 24 hours to spin once. That single number is where the whole idea of a day comes from.
The short version
Day and night are not the Sun switching on and off — they are you being spun toward it and away.
Try it yourself
Shine a torch at an orange in a dark room and turn the orange slowly. Watch a mark on its skin travel through morning, noon and night.
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