News that the European Space Agency’s latest venture to study gravity was successfully underway reached me as I was reading about a related topic today.
According to the book, Beyond the Moon by James Greig McCully, the extra mass and consequently gravitational force at the equator caused by the earth’s spin is near perfectly counteracted in weight terms by the extra centrifugal effect of spinning faster there than at higher latitudes. Nearly perfectly, but not quite.
What does this mean? Well the counteracting effects leave a net result of a person feeling ever so slightly less heavy at the equator than at the poles, less than one fifth of one percent so not a great deal. Still, slightly odd to think that we become heavier by walking north in the northern hemisphere and vice versa. Worth bearing in mind if you’re a boxer or fatfighter at a crucial weigh-in, perhaps.