You weigh 1% less at the equator than at the poles. Earth’s spin is trying to fling you off like being on the outer edge of a merry-go-round. How would you quantify the effect, and differentiate between the poles and equator? I’m sometimes thinking of ways to help flat earthers re-embrace science and this came to mind.
We can calculate the effect from earth’s radius and its spin rate. Someone who weighed 200 pounds at the poles would weigh about 198 pounds at the equator. Don’t worry about gravitational density and the oh-so-slightly flattened shape of our earthly orb.
Measuring the Effect
You don’t have to go to extremes to measure the effect. You weigh less in Miami than New York city, for example, but it’ll be a smaller number.
- Find your latitude on Google maps mobile. Zoom in, then press and hold a point. Most times it will show latitude and longitude although you may have to try different locations that aren’t an address. The first number is latitude which is what we’re after. For example, right now I’m in Memphis, TN which is about 35 degrees North Latitude.
- What’s 1% of your weight? For a 200 pounder it’s 2 pounds. We’ll call that the weight difference.
- Find the effect amount at your latitude. It’s 1% at the equator decreasing to 0% at the poles. Type “cos xx degrees” (in our example that’s “cos 35 degrees”) into Google’s search bar.
- Multiply effect amount (0.81915) by weight difference (2 pounds) to see more exactly how much less you’ll weigh at this latitude than the pole.
Our 200 pounder in Memphis would have a weight difference of about 1.6 pounds. So he would weigh 1.6 pounds more in Memphis than at the poles.
You could do this for Anchorage, AK that is a lot closer to the North Pole which is at 61° N latitude. Cos 61° = 0.48 x 2 pounds = 0.96 pounds. So about a pound less there. 200 pounds at the pole, 199 pounds at Anchorage, 198.4 (200 – 1.6) pounds in Memphis, and 198 pounds at the equator.
There you have it. Sleep well.