Why don't we weigh more at the poles than we do at the equator? © Getty Images

Why don’t we weigh more at the poles than we do at the equator?

We do! But when you do the maths it's not enough to make us take note...

Asked by: Brian McDonach, Sligo

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We do, although you’d barely notice. There are two effects, both due to the spin of the Earth. ‘Centrifugal force’ due to the spinning lowers your body weight by about 0.4 per cent at the equator relative to its weight at the poles. The Earth’s spin also causes the planet to bulge, so that at the equator you’re about 21km further from the Earth’s centre of gravity and so weigh around 0.1 per cent less. Overall you’d weigh around 0.5 per cent less – about a third of a kilo for most of us.


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