The universe is a magnificent thing. It has captured our minds for centuries. Everything about it is interesting and mysterious. From its size, the different celestial bodies it contains, the all-consuming black holes, to the ever-present possibility that there is extraterrestrial life somewhere out there, scientists always have something new to study.
But a solar eclipse, especially a total solar eclipse, has captured our imaginations more than anything else. In the early days, a syzygy (a straight line conjunction of three objects) was considered magical. Whenever it occurred people thought that it was supposed to bring forth some divine or demonical entities, that somewhere some interdimensional portal may have been opened.
Today, people flock together in bunches to observe something that they considered a once in a lifetime phenomenon- when in all honesty it is going to happen again in about 20 months, give or take a couple of months.
The next eclipse is scheduled for 2019, and people can observe it as it passes over the Pacific Ocean. The reason most people think they are so rare is that a lot of time needs to pass before it occurs in the same location again. It takes hundreds of years for an eclipse to occur in the same place again. Unless you are ready to travel to different locations around the globe, you are bound to miss most of them. So generally, most people only see one during their entire life. But even that one eclipse is beautiful enough and makes people feel special as they witness it.
If a person was diligent enough, it is possible for them to see an eclipse every 18 months. And that is only if you chase total eclipses. If you take partial and annular eclipses into consideration, that number becomes even bigger. A partial eclipse occurs, as its name implies, when the moon only partially covers the sun. On the other hand, during an annular eclipse, the moon is directly in the way of the sun but it is not close enough to Earth in order to completely block out the Sun.
Why Does an Eclipse Occur?
A total eclipse similar to the one that happened during the month of August over America is possible only when the moon is close enough to the Earth and directly aligned with the Sun. So the most important part here is the moon and the way it goes around the Earth. All this is connected to the phases of the moon, specifically to the new moon and full moon phases. During its trajectory, the moon goes around the Earth every 28 days. It passes from full to new and back again. The only part of the moon visible during its pass over Earth is the part that is illuminated by the Sun. Some people might think that the moon emits its own light, when in fact it only reflects the Sun’s rays. As it passes by the Earth, the moon reflects a quarter, then half, and finally the entire amount of rays directed towards it. This means a full moon is visible only when the moon is behind Earth. This does not make complete sense, and if the moon is behind the Earth a total lunar eclipse should be visible. This is true but only until you take all factors into consideration. Similar to the total eclipse, a total lunar eclipse only happens if the moon is at a set distance from the Earth. This is also something that does not occur on a monthly basis. And when it does happen the moon is blood red. This is because of the Earth’s atmosphere and the way it reflects the Sun’s rays or any other light that passes through it in fact. The reason this does not happen every month is that the Earth, the Sun, and the moon have to be aligned in the same plane, and this is simply not the case.
For an eclipse to occur everything has to be lined up perfectly. The reason this does not happen is that the Sun and our moon do not travel in the same, even plane. The moon orbits around the Earth at an angle, and because of this, it is a couple of degrees off whenever the three celestial objects are supposed to be aligned. Due to this misalignment, even as the sun casts a shadow, the shadow itself misses the Earth. This is when a partial eclipse occurs, and they are much more common than their total counterparts.
This is what makes the eclipse, be it a solar or lunar one, so interesting and captivating. Everything has to align perfectly; it has to be at the perfect angle and an exact time. Such occurrences are hard to recreate in a lab, let alone to have them happen naturally.
The Final Eclipse
Unfortunately, solar eclipses are not here to stay. The moon is constantly drifting away from the Earth. Whenever the moon pulls the tide towards it, Earth slows down its rotation the tiniest bit. As this happens, the moon’s orbit grows in size. This is down to the transfer of momentum between the two bodies. Due to this momentum, the moon drifts away from the Earth some two centimeters every year.