Originally published February 22, 2009
The nearer one gets to the North and South Poles, the quicker it gets lighter, day by day, as winter turns to spring. And spring arrives there so quickly that the buds on the trees can burst and open fully in a day.
This accelerated growth is needed because the plants and trees have to cram everything into a short season, before the sun travels towards the other Pole.
Thinking of the northern hemisphere as spring approaches, the rapid increase in the length of the day as the sun moves further away from the equator, and heads north towards the tropic of Cancer sees its light galloping north around the curve of the Earth at an ever-increasing rate.
It is as though the light has climbed up the steep slope leading from the equator, and now it is speeding across the gentle slope towards the top of the world.
There is something of that in every curve. In one direction it is an easy downhill ski slope, becoming steeper as it progresses. Looked at the other way, it is like a tough climb that tops out in an easy clamber over a grassy slope.
Now that the days are already becoming lighter, things look brighter. In the depths of winter. In Roundly Park in Leeds at 52° north, it seemed just a couple of short weeks ago that the dreary darkness would last forever. Now the bare tree branches have a tinge of green. Soon the buds will open.