Here is The Weather Channel’s chart of average sunrises and sunsets for January. According to it, sunrise in my neck of the woods will continue to come later and later until the middle of January, when it will start to come earlier.
Even more freakishly, according to the December chart , December 29th is on average one minute shorter than December 28th, even though the days are allegedly getting longer after December 21. Also, the sunrises later just about every day in December, even after December 21.
What in the name of corn?!! I had always thought that the days get longer due to earlier sunrises and later sunsets, not later sunrises and (relatively) much later sunsets. Could anyone explain to me this bizarre astronomical/meteorologic phenomenon?
We need to know when he have to get up to watch the sunrise on the beach.
Well, it’s been almost an hour an not answer so here is an heuristic one. Maybe the Bad Astronomer or another astronomer will be along to do better.
The earth is rotating and let’s call the “night” the period from sunset to sunrise. At the same time that the earth rotates it is moving in orbit around the sun. Because of this orbital motion during the night, the earth has to rotate just a trifle more than would be the case for a non-orbiting earth and this delays the sunrise just a tad. The same thing happens, of course, curing the daylight period and the sunset is also delayed just a little bit
Now, around the solstice (sun stationary), the sun is almost stationary in north-south movement, but after the exact solstice the sun starts to come north so this delays the sunset just a little more than was the sunrise.
Because at time the around the solstice the sun is only moving northward very slowly the sunrise can be delayed whereas, latter on when the sun moves northward much faster this fast northward movement swamps out the slight delay in surise resulting from the orbital motion and sunrise also starts to get earlier.
Since I’ve been a long-time early morning runner, I know that where I live the sun rises the latest on January 11, and the time then is 7:34 EST. The days begin to get longer, however, around the winter solstice since the sun then begins to set later, and the time it sets later is greater than the time it continues to rise later.
