Although images taken from spacecraft show the spherical nature of our planet, Earth is in fact not perfectly spherical – instead, the Earth’s shape is described as an ‘oblate spheroid’.

Earth is around 43km wider when measured at the equator than when measured from pole to pole. If the Earth had to be shrunk down to a diameter of around one kilometre at the equator, the pole-to-pole diameter would be around 997 metres – around three metres short of the equatorial diameter.

This discrepancy arises as a result of the centrifugal force, due to our planet’s constant rotation. Although the Earth takes 23 hours, 56 minutes and four seconds to complete one full rotation, that translates to a whopping speed of around 460 metres every second at the equator!

The resulting bulge at the equator, although relatively small, is still more than twice the largest discrepancies in the Earth’s surface due to the highest mountains or the deepest trenches.

Earth is not the only planet that experiences such a bulge either. Jupiter has an extremely prominent bulge – its equatorial diameter is 142, 984km, an astounding 9,276km more than its pole-to-pole diameter of 133,708km. This is due to its extremely fast rotation rate – Jupiter completes one full rotation in just nine hours and 55 minutes!