Grown-up notes

Each line is marked Fact well established, Model a deliberate simplification, or Unsure not settled.

Play another way

Another connection: Where are we?

The idea

• FactThe Earth is a ball that turns right round about once every 24 hours.
• FactThe Sun lights only the half of the Earth that faces it. It is day where you are when your part of the Earth faces the Sun, and night when it has turned away.
• FactThe Sun does not go round the Earth. It looks as if it crosses the sky from east to west because the ground under us is turning from west to east.
• FactSeen from above the North Pole the Earth turns anticlockwise. The toy looks down on the South Pole, so that Australia is in view, and from there the same turning is clockwise. The grey arrow beside the Earth shows the real direction.
• FactFrom Sydney the midday Sun is in the northern sky. The Sydney picture looks north, so the Sun travels from the right (east) to the left (west).
• FactThe green dot in "Other side" is Rio de Janeiro in Brazil. When it is midday in Sydney it is about ten or eleven o'clock the night before in Rio.
• FactThe Moon does not make night. It shines by reflecting sunlight and is in the sky in the daytime about as often as at night, which is why the toy shows it on some afternoons.
• FactThe ground at Sydney is carried east at roughly 1,400 kilometres an hour. We feel nothing because the turning is smooth and everything around us moves along with us.

What the pictures simplify

• ModelNot to scale. The Sun is about 109 Earths wide and nearly 12,000 Earth-widths away. On this scale it would be a ball several houses tall, far down the street.
• ModelNo tilt. The real Earth leans over by about 23 degrees. That makes summer days long and winter days short, and gives us seasons. The toy leaves it out, so each turn is exactly half light and half dark. Real daylight is only approximately half a day near the equinoxes; the atmosphere and the Sun's apparent size affect sunrise and sunset.
• ModelShe can turn it backwards. The real Earth only ever turns one way. Turning it back by hand is like rewinding. Let go and the toy only ever coasts the real way.
• ModelShe can stop it. The real Earth does not stop. Stopping it freezes the day in this toy, which leaves out Earth's journey around the Sun. A real non-spinning Earth would still change its orientation to sunlight during that yearly journey.
• ModelThe Moon is held still a quarter of the way round from the Sun, as a half Moon. The real Moon goes round the Earth about once a month, so it rises later each day and its shape changes.
• ModelOne spin, one day. Measured against the Sun a day is 24 hours. Measured against the stars the Earth turns once in 23 hours 56 minutes; the extra four minutes come from the Earth moving along its path round the Sun.
• ModelThe still Sun. The Sun is itself moving through our galaxy and carries the Earth with it. It does not move round us.
• ModelRough drawing. The land shapes are cartoons, the sky colours are simplified, and the stars do not drift.

Questions she may ask

• Where does the Sun go at night? FactNowhere. It is still shining, on the other side of the world. We have turned away from it.
• Why can't we feel the Earth spinning? FactWe, the ground and the air are moving together. Earth's turning changes too gently for us to notice unaided. It is not perfectly steady: its rate varies, and tides slowly change it over long times.
• Will we fall off? FactNo. The Earth pulls everything towards its middle, so "down" means towards the middle wherever you stand.
• Why can I see the Moon in the daytime? FactThe Moon is up for about half of every day, and it is bright enough to see against a blue sky.
• Why is it still light at bedtime in summer? FactBecause the Earth leans. In summer our half leans towards the Sun and spends more of each turn in the light. That is a story for another day.
• Why does the Earth spin at all? FactIt inherited spin from the material and collisions that formed it. The Moon's tides have gradually slowed Earth's rotation over long times. UnsureExactly how the young Earth came to spin the way it does is not settled. A leading idea is a giant collision long ago that also made the Moon.

Words this guide teaches

Earth: the huge ball we all live on. Spin: to turn round and round on the spot. Sunrise: the moment our part of the Earth turns to face the Sun.

Go further

Sydney Observatory on Observatory Hill, Millers Point, runs guided tours with telescopes, and has family tours for ages six and up. Tours must be booked, and conservation works may close some areas, so check the Observatory's page before you go. The park around it is free and is a good place to watch a sunset.

Sources

• NASA, "What We Learn About Earth By Studying the Moon": tides gradually slow Earth's rotation.
• NASA Space Place, "How Long Is One Day on Other Planets?": a day against the Sun is about 24 hours; against the stars, 23 hours 56 minutes.
• NASA StarChild, "Why do we have day and night?": the Earth turns us towards and away from the Sun.
• Wikipedia, "Earth's rotation": eastward turning, anticlockwise seen from the north, and about 1,675 km/h at the equator.
• Powerhouse, Sydney Observatory: visiting.

Checked November 2026. The speed at Sydney, the height of the midday Sun, the Rio time difference and the Sun's size and distance are worked out from standard figures rather than taken from a linked page.