A Solstice Guide

Ok, today, being the 21st of June, is the summer Solstice here in the Northern Hemisphere, and the Winter solstice in the Southern, and well, I thought that a brief explanation of what they are, and why they occur might be in order, as it seems to be an event that is almost taken for granted during the modern era.

Well, as to why it occurs, this is also due to the reason that seasons occur, and equinoxes happen as part of this. They all occur because the Earth is tilted upon its axis by between 22.1 and 24.5 degrees. This tilt, whilst being a relatively small angle has the ability to ensure that the two hemispheres of the Earth (northern and southern) have different exposure to the sun at all times during the year, causing the natural seasons to occur.

It also means that, on certain days in the year sunrise and sunset occur roughly 12 hours apart, these being called equiluxes, and these are usually mistaken for exquinoxes. Rather, an equinox is when the sun is aligned with the Earths equator, meaning that the axis is tilted neither away nor towards the sun. Hence the equinoxes occur in spring and autumn.

Right, so let us now return to Solstices, as this is our main topic today. The sun appears to be at its most northern and southernmost points in the sky, depending on which hemisphere you are in (if you are in the northern hemisphere, when the sun is at its most northern point, this is the summer solstice, and is the winter solstice for the southern hemisphere. And when the sun is at its most southern position, it is the winter solstice for the northern hemisphere, and the summer solstice for those living south of the equator.) It’s is called a solstice, from the Latin meaning "sun to stand still", due to the apparent movement of the sun in the sky stopping, before reversing direction.

It occurs because of the tilt of the earth’s axis, which means that each hemisphere is either facing away or towards the sun, and these solstices happen when the process reaches its extremes, so when the northern hemisphere is facing the sun at its maximum exposure, this is a summer solstice for the northern hemisphere, and a winter one for the southern hemisphere, and vice versa.

I hope that this has cleared up any existing confusion about solstices, equinoxes and equiluxes.