Hello friends! In this article, we would be providing answers to the question “why don’t we have a solar eclipse every month?”.
If that is what you’re looking or searching for, then congratulations, you’ve made it to the right place.
Quite contrary to what a lot of people think, eclipses are quite common on Earth.
It is estimated that the Earth experiences 2 to 5 eclipses a year (so that makes about 66 eclipses in a century, so they definitely aren’t rare).
Still, judging from the literal definition of an eclipse and how common it is on earth, we should have at least 1 eclipse a month.
But sadly that is not the case, and there’s a reason why.
This article is all about eclipses, you’ll be learning a lot. So I advise you to get a glass of something chill and enjoy reading.
The reason we don’t have a solar eclipse every month is simple: most times the angle of inclination of the moon to earth is higher than the ecliptic plane.
What Are Eclipses and How Do They Work?
The best start to answering the question “why don’t we have a solar and lunar eclipse every month?”
Would you choose to understand in detail, the literal definition of an eclipse or rather understand what an eclipse is all about?
So what is an eclipse? Well, an eclipse is a big event.
It occurs when a heavenly body or spacecraft or astronomical object is obscured or blocked temporarily by another heavenly body or astronomical object.
This is achieved by passing through the shadow of the heavenly body or by having a different heavenly body pass between the viewer and it.
We can call this alignment of three Celestial or heavenly bodies a ‘syzygy’.
Note: An eclipse can also occur when a spacecraft positions itself in such a way that it would be able to observe two heavenly or celestial bodies that are in alignment.
Different Kinds of Eclipse
Now when it comes to eclipses, two particular types come to mind, the Solar eclipse and the Lunar eclipse.
They are both special events but trust me like we already established they are quite common as at least one of each occurs a year.
There are other forms and types of eclipses, for instance, a binary star produces an eclipse if its constituent star’s plane of the orbit is intersected by the position of the viewer.
For now, however, let’s focus on the two types of eclipses.
The Lunar Eclipse: A Brief Overview
The first type of eclipse we would be looking into would be the Lunar eclipse. Now this kind of eclipse event can occur in a variety of ways.
One would be when the moon positions itself in the shadow of the earth.
Another would be through syzygy (remember syzygy?).
When the Moon, the Sun, and the Earth are in exact alignment or at least, very closely aligned.
But some conditions need to be met.
- First, the Earth has to be aligned in between the other two celestial bodies (i.e, between the moon and the sun).
- Secondly, It has to be a full moon night.
You can view a lunar eclipse from any side of the Earth that happens to be at night time during the duration of the Lunar eclipse.
And on average, a total Lunar eclipse could last as long as 2 hours.
This is in contrast to the Solar eclipse which only lasts a few minutes. This happens because the shadow of the Moon is a lot smaller than the Sun’s shadow
Note: The exact type of lunar eclipse that occurs, and how long it lasts depends on the closeness of the moon to any of the other heavenly bodies in the syzygy alignment.
As the title has already pointed out, there are basically two types of Lunar eclipses in existence, the total lunar eclipse, and the central lunar eclipse.
The Central Lunar Eclipse
During the Central lunar eclipse, the moon would pass through the middle of the Earth’s shadow.
Meeting the Earth’s antisolar points. Usually, this type of lunar eclipse is quite rare.
The length of a solar eclipse can be affected by the relative distance of the Earth from the moon during the solar eclipse.
Most especially when the moon is close to the apogee, which can be defined as the farthest point in orbit from the earth, its orbital speed is the slowest.
The Earth’s umbra diameter does not decrease significantly with changes in the orbit distance of the Moon.
Therefore, a fully eclipsed moon near the apogee will lengthen the overall period
The Total Lunar Eclipse
A total lunar eclipse occurs when the Earth’s umbra entirely covers the moon.
When the moon enters the total lunar eclipse, the entire surface becomes brighter almost evenly.
Then, when the sun hits the far end of the moon, the entire disk darkens again.
This happens because the brightness of the edge of the moon as seen from Earth is generally larger than the brightness of other parts of the surface.
This is due to the reflections from the irregularities of many surfaces within the edge.
The sunlight that hits these irregularities would always be reflected more than it hits.
The more central part, and therefore the edge of the full moon, generally looks brighter than the rest of the lunar surface.
The solar eclipse usually occurs during the passing of the moon between the Sun and the Earth.
This passing of the moon partially or totally blocks the view of the sun from the Earth.
The new moon usually coincides with such an alignment, this indicates that the moon is so close to the Earth’s orbital plane.
During the total solar eclipse, the sun's disk is completely covered by the moon.
Only part of the sun is hidden during the annular and partial solar eclipses.
Here, you’ll find a detailed explanation of the different types of eclipses we have.
The Total Solar Eclipse
This sort of solar eclipse happens when the moon’s dark silhouette completely blocks the Sun’s very intense bright light, revealing the much darker sun corona.
The Partial Solar Eclipse
For the partial eclipse to occur, the Earth’s alignment with the Moon and the Sun won’t be perfect.
The moon would only partially hide the sun causing its rays to spill out.
This phenomenon is usually visible from most of the Earth outside the total or annular solar eclipse pathway.
Note: It could be really dangerous to look directly into a partial solar eclipse.
A partial eclipse could intensify the rays of the Sun so it is advised you wear protective eyeglass.
From all that has been said, it has been established that a solar or lunar eclipse occurs each time there’s an alignment between the Earth, Sun, and the Moon.
Now from what we know, the moon usually takes a month to orbit but we clearly don’t have eclipses every month.
So, Why Don’t We Have a Solar Eclipse Every Month?
Well, it’s all about the angle of alignment. You see, to get an eclipse, the Moon, Sun, and Earth would have to be perfectly aligned.
But this is not the case, as most times the Moon is usually on an inclined plane when compared to the Earth.
To simplify this for you, picture the solar system as a flat disk, where all the planets in the solar system are arranged on.
You can call this the Ecliptic plane.
Now also picture the Moon as being on another disk that is inclined at 5.14 degrees to the Earth.
Now following the Moon’s orbit around the Earth, It could sometimes be below the Ecliptic plane and sometimes be above the Ecliptic plane.
So most times, the Moon’s shadow that is cast, misses the Earth or vice versa. We do however get eclipses when the syzygy is perfect.
So that’s it, all you need to know about eclipses to help you better understand and answer questions like “why don’t we have a solar eclipse every month?”
Eclipses are quite beautiful events that most people would love to experience. And it’s quite sad that we only get to experience them twice or thrice a year.
Regardless, we still appreciate these beautiful astronomical events as they make us marvel at the creation story.
I advise you to check out our previous articles, you might learn something new, for now, stay safe.