summer may be here

The weather forecasts suggest that summer may be arriving. The suggestion is it's going to be warm and sunny for the rest of the week at least, and possibly beyond.

The is slightly weird, because yesterday, Monday the 21st of June, was the official mid-point of summer. The day itself was the Summer Solstice, which is the day with the longest period of sunlight and is apparently named because the Sun (the "Sol" part) appears to hang in the air at mid-day (the "stice").

Each of the seasons are exactly 1 quarter of a year long (so about 3 months) and their centres are marked by the solstice's and the equinox's. The Solstice's mark the 'maximums' of the year, with Summer having the longest day and winter having the longest night.

The Equinox's are the points of equality(Equi - Equal + Nox - Night) where the day and night are exactly the same length. They mark the mid-points of Spring and Autumn.

But hat causes these and what causes seasons? Well, many people believe that summer and winter are caused by the proximity of the Earth to the Sun. I'm not sure where this comes from, but could be because the Earth's orbit is not perfectly circular, but is instead an ellipse.

However, this isn't what causes the seasons or the change of the length of the day. That's due to the fact that the Earth's axis is tilted. Because it's tilted, that means that the northern and southern hemisphere are exposed to different amounts of sunlight.

Now if you think of the earth like a chicken on a spit-roast over a fire, you can see that if the spit was tilted, the chicken would not cook evenly. Well those are the seasons - the tilting means each hemisphere spends disproportionately longer in the sun than the other as the year goes on. It's also why once you get far enough north or south you have days where the sun never sets and never rises.

I'm not sure quite why I'm blathering on about this stuff, other than I find it fascinating.

I also guess I'm going to have to start using the old aircon. Luckily a side effect of all the sorting out has been that my aircon is now set up and ready to go - I won't need to spend a sweaty half hour moving crap out of the way so that I can turn it on this evening.