Hexbyte – Tech News – Ars Technica |
To be pedantic, daylight/sunrise/sunset times are actually a little bit different than being able to use straight up trig functions.
You know how the planets’ orbits are actually elliptical (oval shaped)? The planet moves faster in its orbit when it’s in the part of the orbit nearer the sun and slower when it’s at the far end.
For Earth, it’s happens that the nearer to the sun or faster part of the orbit occurs in January and the far/slow part happens in July.
The planet is still spinning at the same rate but it’s “scooting” around the orbit at that point in Jan. That means the Earth is moving a little bit more than 1/365 of the way around the sun in a day at the fast part of the orbit so it takes an the Earth an additional few minutes to rotate past 360 degrees fpr the sun to appear at the same spot in the sky. The effect to us with 24 hour clocks is that sunrise happens at the same time but sunset occurs later.
So the clock is faster than the sun in the spring and symmetrically slower in the fall. And the effect is smaller in late spring through early fall when th