3 ms·
> Both the stellar day and the sidereal day are shorter than the mean solar day by about 3 minutes 56 seconds. This is a result of the Earth turning 1 additiona
by rawling 5y ago
> Both the stellar day and the sidereal day are shorter than the mean solar day by about 3 minutes 56 seconds. This is a result of the Earth turning 1 additional rotation, relative to the celestial reference frame, as it orbits the Sun (so 366.25 rotations/y).
https://en.wikipedia.org/wiki/Earth's_rotation https://en.wikipedia.org/wiki/Earth's_rotation
- implements 5y agoSo we would need 367 unique date identifiers … but we’ve only got 366 (Feb 29th being the non-annual one). I get I may be being unintelligent, but isn’t the author confusing the rolling coin paradox with an obscure astronomical reference system and coming up with a ‘mistakenly technically correct’ result that doesn’t match experienced reality?
- kgwgk 5y agoWhy 367 dates? Dates are not used to count Earth revolutions. They are counting days/nights and there are only a bit more that 365 of those in one year.
- rawling 5y agoIt matches experienced reality if you look at the stars rather than the sun, or if you use something like a Foucault pendulum to measure the rotation speed.
- mmmmmbop 5y agoImagine you're standing on a set point on the surface on the outer coin, e.g. the one touching the inner coin. As the outer coin rotates around the inner coin, your experienced reality will be that you see n-1 rotations. In the example of the outer coin having 1/3 the radius of the inner coin, as the outer coin rolls around the inner coin 4 times, you would actually only touch the inner coin 3 times.
- python273 5y agoI made a visualization for > Circle A has 1/3 the radius of circle B, and circle A rolls one trip around circle B. How many times will circle A revolve in total? https://www.shadertoy.com/view/7ddSR2 https://www.shadertoy.com/view/7ddSR2