A WPF 3D simulation to inspect the Equation of Time
Most people living in the northern region of the earth know that on about December 21 winter begins and the days are getting longer again. I always assumed that this is also the day of latest sunrise and earliest sunset, but to my big surprise, this isn't true!
There are several websites around where you can get the times for sunrise and sunset for your geographic location and it turned out that December 12 is the day of earliest sunset, whereas December 30 is the day of latest sunrise.
The reason for this is simple, but not obvious: the days in December are 30 seconds longer than 24 hours! This phenomenon is called 'Equation Of Time' and there are many articles about it in the world wide web.
Some of them are just math - which helps in a certain way, if you just want to do some calculations. Most of them contain pictures - which helps to see what's going on, but none of them did help me to really understand the why.
So I started to write this interactive 3D simulation - and in the end it helped at least me to demystify this strange behaviour. You can use the application to just play around with the sun-earth system, or you can take a demo tour which covers the physics of the Equation Of Time.
