What Is a Blood Moon?

The phrase “Blood Moon” has an eerie ring and tends to make us think of the mysterious effects of the Earth’s moon on our lives. However, while a Blood Moon is undoubtedly fascinating, it’s also an entirely natural astronomical phenomenon that occurs on a predictable and regular basis.

Indeed, Blood Moon is an unscientific term for a total lunar eclipse, a unique event when the moon is entirely in the Earth’s shadow. Earth is the only planet in our solar system with total lunar eclipses because it’s just the right size for its shadow to cover the moon entirely.

Earth’s inhabitants are lucky to experience these lunar eclipses, particularly the spectacular Blood Moon.

Understanding Lunar Eclipses

Before we can get into all the details regarding the Blood Moon and whether it has any critical significance, we first need to understand what lunar eclipses are in the first place.

A lunar eclipse occurs when the Earth is wholly or partially aligned between the moon and the sun, thus casting a shadow onto the moon’s surface.

This can only occur during a full moon when the moon is opposite the sun during its orbit around the Earth. While we might observe a full moon for a few days, astronomers regard it as a singular, precisely defined occurrence.

The Earth can block the sun’s light from reaching the moon partially or fully. Either way, this event is referred to as a lunar eclipse. The sun’s light still manages to reach the moon, and that’s why we can see it, but the moon’s visibility is reduced.

You might wonder why you don’t see a monthly lunar eclipse. That’s because not every full moon is simultaneously a lunar eclipse. The moon takes 29.5 days to circle the Earth, but its orbit is tilted at about 5 degrees in respect to our planet’s orbit around the sun.

The moon frequently goes below or above the Earth’s shadow as it orbits. But when the Earth’s and the Moon’s planes coincide, the total lunar eclipse or the Blood Moon occurs.

Three Types of Lunar Eclipses

When the Earth eclipses the sun, it casts two types of shadows that land on the moon. The larger shadow is called the penumbra, and the smaller shadow is called the umbra. Considering the Earth’s shadows, we can classify three types of lunar eclipses.

Penumbral Eclipse

As the name implies, the penumbral eclipse occurs when the moon passes the Earth’s larger shadow. It’s important to point out that this cosmic event is quite subtle and nearly invisible to the naked eye. During the penumbral eclipse, our moon will appear only slightly darker than it usually does.

Partial Lunar Eclipse

Unlike the penumbral eclipse, you can easily notice the partial lunar eclipse. This type of eclipse happens when the Earth, sun, and the moon aren’t perfectly aligned, and only one section of the moon passes through the umbra shadow.

You can see a very dark shadow on one side of the moon, but the rest of the moon appears precisely as the full moon does typically.

Total Lunar Eclipse

Finally, the total lunar eclipse, or the Blood Moon, occurs when the Earth, sun, and moon are perfectly aligned. As a result, the moon is fully enveloped in the Earth’s umbral shadow, darker than the penumbral shadow, making the moon appear rusty red or ruddy brown.

The red wavelengths of light of the Earth’s atmosphere are bent inward in the moon’s direction, making it appear a deep-red color. However, the exact hue of the red can drastically differ depending on several factors.

Pollution, dust, cloudiness, and the current general condition of the Earth’s atmosphere all impact the visibility and appearance of the Blood Moon. For example, recent volcanic activity can make the Blood Moon appear much darker, sometimes dark gray or black.

How Often Does a Blood Moon Happen?

Did you know the first recorded total lunar eclipse was in China around 3,000 years ago? Mention of the “Red Moon” appear throughout history and even have a special reference in the voyages of Christopher Columbus.

Is a Blood Moon a rare occurrence?

One could argue that the Blood Moon is a relatively rare astronomical event. But scientists are reluctant to see it that way, especially compared to other, more infrequent events, such as Halley’s Comet, which passes the Earth every 75-79 years.

The good news is that most people will be able to see the Blood Moon because they can happen on average twice every three years. It’s also not uncommon for a Blood Moon to occur twice in the same calendar year.

It’s essential to remember that this is the average spacing of the Blood Moon event, which is not precise. However, astronomers can predict when the total lunar eclipses happen, even decades into the future, giving you a chance to plan and see it when it happens.

How Long Does a Blood Moon Last?

There’s a common misconception that lunar eclipses last only a few minutes, which is not unusual, given that solar eclipses are typically that short.

On the other hand, lunar eclipses, including the Blood Moon event, can last anywhere from 30 minutes to three hours, though the average duration is around one hour.

The longest lunar eclipse was recorded in 1440, lasting 3 hours, 28 minutes, and 46 seconds.

When the next Blood Moon approaches, astronomer communities typically highlight all the details about the starting point and the duration of the event, allowing people to plan for the viewing accordingly.

What Is a Super Blood Wolf Moon?

You might have heard the term “Supermoon,” which describes the event when the moon is closest to the Earth and appears somewhat more prominent and brighter.

When the Supermoon occurs during the first full moon of a calendar year, it’s called the “Wolf Moon.”

If the total lunar eclipse appears during the Wolf Moon, that is called Super Blood Wolf Moon. This event is understandably rare, and the last recorded instance occurred on January 21, 2019.

Does the Blood Moon Have Any Special Significance?

In strictly scientific terms, the Blood Moon doesn’t hold any particular significance. It’s a regularly occurring astronomical event that, regardless of its spectacular appearance, doesn’t offer any remarkable scientific insight.

But for humans, the Blood Moon has historically held significant meaning, and that’s true even today. The Blood Moon is mentioned in religious books and remains an important segment of astrology.

The Blood Moon was feared and seen as a bad omen due to its appearance and color. But these days, as we know precisely what the Blood Moon is, it allows us to appreciate this phenomenon better.

How to Watch the Blood Moon

Unlike the solar eclipse, you can observe the lunar eclipse with the naked eye, as there’s no fear of damaging your eyesight. You also don’t need special equipment to enjoy the moon going through the Earth’s umbra, though binoculars or a telescope may enhance the experience.

There’s typically no need to stay up very late to see the Blood Moon, as the process starts right around sunset and ends an hour or so later.

Keep in mind that each Blood Moon event is visible from one half of the planet at a time, so if it’s your turn, all you need to do is stand outside and enjoy the fantastic color transformation of the moon.

What Is a Lunar Tetrad?

Astronomers sometimes talk about the Blood Moon in the context of four total lunar eclipses, an event referred to as lunar tetrad. However, these consecutive total lunar eclipses can occur every six months, which is rare.

The frequency of lunar tetrads varies, though they can be predicted. For example, from 1582 to 1908, there were no lunar tetrads, but in the next 250 years, there were 17 of them. The 21st century will have eight lunar tetrads, two of which have already occurred.

What Is a Blue Moon?

Learning about the Blood Moon, or the Red Moon as it’s often called, might make you curious about the Blue Moon’s significance. The phrase “once in a Blue Moon” indicates that it’s a rare occurrence, but is it really?

The Blue Moon isn’t blue. It’s merely a term introduced in the 16th century to describe something impossible. But when the Krakatoa volcano erupted in 1883, there were reports that the moon looked blue. So the term “Blue Moon” went from representing something impossible to something rare.

In scientific terms, a Blue Moon is a second full moon in one calendar month. Usually, one year has 12 full moons, but every two and a half years, we also get full moon number 13, also known as the Blue Moon.

Some might consider that a Blue Moon happening every two and a half years isn’t that rare, but at least we know how it got its name.

Appreciating the Moon and All Its Colors

The moon has always fascinated humans, and even with scientific discoveries that have helped us know more about it, we continue to appreciate it. The Blood Moon is a beautiful, mysterious, and familiar cosmic event.

The Earth’s umbral shadow eclipses its only satellite planet, and the result is a sunset-red color that we can admire with the naked eye. To enjoy it, all you need to do is glance through the window or find a nice spot in the yard and hope for the clouds to clear.