Solar eclipses occur when the moon moves between the Sun and the Earth, temporarily obscuring sight of the Sun. For many, they are awe-inspiring events that bring the realities of nature and the universe around us to our doorstep. There are four main types of solar eclipses and they are explained below.
1) Total eclipse. The event where the Sun is completely blocked by the moon is known as a total eclipse. The moon’s dark shadow completely overtakes the sun in the sky, with a faint corona. The corona is the “plasma atmosphere” of the sun. During an eclipse, only a small region of the surface of the Earth is able to see the total eclipse. A total eclipse occurs somewhere on Earth every 18 months, on average. However, many of these can occur over regions of ocean or the antarctic, making viewing nearly impossible. Mathematically, a region is estimated to see a repeat total eclipse every 370 years, making this a very rare occurrence. They last only a few minutes long, with very few lasting more than 7 minutes (once every 100 years).
2) Annular eclipse. An annular eclipse occurs when the moon is blocking part of the sun and is perfectly in line, but the size of the moon is such that it does not cover the entire sun. The bright ring that is formed by the sun is referred to as an annulus.
3) Hybrid eclipse. These rare occurrences are when certain regions of the Earth can see a total eclipse and other regions can only see an annular eclipse.
4) Partial eclipse. A partial eclipse occurs when the moon only partially blocks the sun because the two bodies are not perfectly in line. Large portions of the Earth can usually see this when a small portion is witnessing the annular or total eclipse. Because of the angle of view, some partial eclipses are only visible as partial eclipses, without an accompanying annular or total eclipse.
Because of the relatively well understood nature of the movement of the moon, Earth and the Sun, eclipses are relatively easy to predict. Many worldwide travel to regions to witness the rarer of the eclipse events, specifically the total eclipses. Because of the elliptical nature of planetary orbits, certain months of the year favor total eclipses over alternative eclipse events. The aphelion, in July, is the period when the Earth is farthest from the Sun and often results in total eclipses (the Sun is smaller relative to the moon and can be fully obscured). In January, known as the perihelion, the Sun is closer and annular eclipses are much more likely.