We explain what a lunar eclipse is, how and when this phenomenon occurs. In addition, the types of lunar eclipse and how is a solar eclipse.
What is the lunar eclipse?
Eclipses, both lunar and solar, are astronomical events that occur from time to time. In the case of the lunar eclipse, the Earth stands between the moon and the sun and the three celestial bodies remain aligned for a time in that order. Thus, for a few minutes, it is the Earth that overshadows the moon, and not vice versa. For this to happen, in addition to the alignment, the moon must be full.
Instead, a solar eclipse occurs when the moon stands between the sun and the Earth , which makes the sun from our planet cover. In this case, the moon must be new and the three celestial bodies must also be aligned.
According to experts, each year, one to four, five or even six lunar eclipses are recorded.
How does a lunar eclipse occur?
As previously explained, a phenomenon such as the lunar eclipse occurs when the full moon is covered by the shadow generated by the planet Earth. Is that there is a fact that is worth clarifying: it is thanks to the sunlight that from our planet we can see the moon.
That is why when there is a lunar eclipse, we see how the Earth’s shadow begins to advance, covering the lunar surface . Within that shadow we speak of two different parts: the penumbra and the umbra. While the latter is the area of the moon that is completely covered under the shadow – and, therefore, it is imperceptible -, in the case of the penumbra the shadow is more tenuous.
How often does a lunar eclipse occur?
Although the moon revolves around the Earth every month, lunar eclipses do not occur 12 times a year. The explanation is simple: the path that the moon makes around the planet is inclined about five degrees, if compared with the path that the Earth makes around the sun. This means that the moon is not always reached by the earth’s shadow.
The moon can be behind the Earth and even receive sunlight. That is why everything will depend on where on Earth the person is at that moment : it must be in the middle of the planet at night. Otherwise, you will not register it.
That is why, although lunar eclipses are events that occur from one to four, five or even six times in a year, from the same place on the planet you can see several eclipses, as long as they occur at night . This is different from what happens with solar eclipses that, according to NASA, can be seen, from the same place, once every 375 years, on average.
Types of lunar eclipse
According to the proportion in which the Earth’s shadow is cast on the surface of the moon, in addition to the part (umbra or penumbra) the scope, different types of lunar eclipses can be identified:
- Total eclipse. In this case, the Earth’s shadow manages to cover the entire surface of the moon.
- Eclipse penumbral. This event happens when the moon barely crosses the area of the penumbra – and not that of the umbra. That is why this event becomes more imperceptible. Within the penumbral eclipse there are two subtypes. The total, which is when the entire surface of the moon is reached by the penumbra, while, in the partial, only part of the moon. In one year, it is estimated that one of each eclipses are of this type.
- Partial eclipse. This event is recorded when only a portion of the surface becomes reached by the umbra.
Conversely, the solar eclipse develops when the moon hides the sun. When does this happen? When the moon is located between the Earth and the sun aligned .
There is talk of a total solar eclipse when the lunar shadow manages to cover the entire surface . This phenomenon lasts no more than a couple of minutes. Meanwhile, the partial solar eclipse is when the lunar shadow fails to cover the entire surface. That is why, from the Earth you see a fragment of it, bright.
The annular solar eclipse , on the other hand, is when the moon and the sun are aligned , but, since it is smaller, a kind of ring of light is perceived. Finally, there are those who speak of the hybrid solar eclipse, which is when, from certain angles of the earth’s surface it is seen as annular, while, from other angles, as a total.
The total solar eclipses occur every 500 days , ie every year and a half, approximately. While partials are more frequent: two a year, on average.
Unlike lunar eclipses, seeing a solar one is a challenge . It is that there are two, at least, the conditions that must be given. On the one hand, the person who wants to see it must be somewhere on the planet from which the moon’s path is located. On the other hand, it has to be daytime in the place where that person is at the moment the three celestial bodies line up.
It is important that, when you want to appreciate a phenomenon like this, you should not look directly at the sun, because it can damage your eyesight . Instead, you can filter or different techniques to appreciate them. Or else, using different projection techniques suggested by specialists.