Spinning Sun

A boy and girl standing next to a small basket ball on top. In the background are yellow and blue information panels.
A boy and girl standing next to a blue and beige round table that has a small basket ball on top. In the background are yellow and blue information panels.

The Sun spins, causing it to bulge around its equator.

How it works

Spin the wheel and watch what happens to the model Sun.

Things to try or ask around the exhibit

  • What change in shape do you notice when the Sun ball is spinning, compared to when it's stationary?
  • If the ball was made from gas instead of solid material, how would that affect the spinning motion?

Background

The ball represents the Sun, so when it spins, it represents the Sun as it spins. The Sun spins very fast on its axis. The outer layers of gas tend to travel in a straight line and move further away from the centre (like spinning pizza dough). This causes a slight outward bulge at the Sun's equator of 1 to 6 kilometres, and flattens the Sun's shape slightly.

Finding the science in your world

Earth's equator also bulges slightly as it spins on its axis. Therefore, Earth is also shaped like a slightly flattened sphere.