We explain what a lunar eclipse is, how and when this phenomenon occurs. We also explain the types that exist and what a solar eclipse is like.
What is a lunar eclipse?
Eclipses, both lunar and solar, are astronomical events that occur periodically. In the case of a lunar eclipse, the Earth comes 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 shadows the moon, and not the other way around. For this to happen, in addition to the alignment, the moon must be full.
On the other hand, a solar eclipse occurs when the moon comes between the sun and Earth, causing the sun to be obscured from our planet. In this case, the moon must be new, and the three celestial bodies must also be aligned. Must Read About Color Once.
According to experts, between one and four, five, or even six lunar eclipses are recorded each year.
How does a lunar eclipse occur?
As previously explained, a phenomenon like a lunar eclipse occurs when the full moon is obscured by the shadow cast by planet Earth. There is one fact worth clarifying: it is thanks to sunlight that we can see the moon from our planet.
This is why, when there is a lunar eclipse, we see the Earth’s shadow begin to advance, obscuring 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 hidden in shadow—and therefore imperceptible—in the case of the penumbra, the shadow is fainter. Must Read About Color Theory Once.
How often does a lunar eclipse occur?
Although the moon orbits the Earth every month, lunar eclipses don’t occur 12 times a year. The explanation is simple: the path the moon makes around the planet is tilted about five degrees compared to the path the Earth makes around the sun. This means the moon isn’t always caught in the Earth’s shadow.
The moon can be behind the Earth and still receive sunlight. Therefore, it all depends on where the person is on Earth at the time: they must be on the half of the planet where it’s nighttime. Otherwise, they won’t notice it.
Therefore, although lunar eclipses occur one to four, five, or even six times a year, several eclipses can be seen from the same location on the planet, as long as they occur at night. This is different from solar eclipses, which, according to NASA, can be seen from the same location once every 375 years, on average.
Types of Lunar Eclipse
Depending on the extent to which the Earth’s shadow is projected onto the surface of the moon, as well as the part (umbra or penumbra) it reaches, 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.
- Penumbral eclipse: This event occurs when the moon barely passes through the penumbra—and not the umbra. This is why this event is less noticeable. Within the penumbral eclipse, there are two subtypes. A total eclipse occurs when the entire surface of the moon is covered by the penumbra, while a partial eclipse occurs when only part of the moon is covered by the umbra. In a given year, it is estimated that one in three eclipses is of this type.
- Partial eclipse: This event occurs when only a portion of the surface is covered by the umbra.
Solar Eclipse
Conversely, a solar eclipse occurs when the moon obscures the sun. When does this occur? When the moon is aligned between the Earth and the sun.
A total solar eclipse is defined as one when the lunar shadow covers the entire surface. This phenomenon lasts no more than a couple of minutes. A partial solar eclipse occurs when the lunar shadow doesn’t cover the entire surface. This is why, from Earth, only a bright fragment of it is visible.
An annular solar eclipse, on the other hand, occurs when the moon and sun are aligned, but since the moon is smaller, a kind of ring of light is visible. Finally, some people speak of a hybrid solar eclipse, which occurs when, from certain angles of the Earth’s surface, the eclipse appears annular, while from other angles, it appears total.
Total solar eclipses occur every 500 days, or approximately every year and a half. Partial eclipses are more frequent: twice a year, on average.
Unlike lunar eclipses, seeing a solar eclipse is a challenge. At least two conditions must be met. First, the person who wants to see it must be somewhere on the planet within the path of the moon. Second, it must be daytime in the location where that person is located when the three celestial bodies align.
It is important that, when viewing a phenomenon like this, one should not look directly at the sun, as this can damage one’s eyesight. Instead, filters or different techniques can be used to appreciate them. Alternatively, different projection techniques suggested by specialists can be used. Must Read About Comparative Table Once.
References
All the information we offer is backed by authoritative and up-to-date bibliographic sources, ensuring reliable content in line with our editorial principles.
- “Facts you need to know about the blood moon eclipse” on Ecoosfera.
- “Eclipses” on Astrosurf.
- “Eclipses” at NASA Space Place.
- “Outreach” at the Canary Islands Institute of Astrophysics.
