A lunar eclipse is a major astronomical phenomenon that happens as the full moon falls into the Earth’s shadow. The shadow, or umbra, blocks the sun’s light that is ostensibly reflected on the moon.

Facts About Lunar Eclipse
Image by adege from Pixabay

The moon’s position relative to its orbital nodes impacts the lunar eclipse type and duration. The full moon is reddish-brown during a lunar eclipse, because the light of the Sun bends through the Earth’s atmosphere and reflects off the moon.

Since the occurrence of a lunar eclipse is very normal, broadening our knowledge about such astronomical phenomenon is important. This way, if ever anything happens, people would have an understanding of the situation. Here are some fun facts about the lunar eclipse. 

1. Occurrence

There are 85 total lunar eclipses during the 21st century; a single geographic position on the Earth’s surface would be able to see an average of 40 to 45 complete lunar eclipses, or around one every 2,3 years. Contrast this with a total eclipse of the sun, which occurs on average about every 375 years as seen from a specific geographical location.

The explanation for the substantial difference is clear. To see a complete eclipse of the sun, you must fortuitously place yourself in the path of the dark shadow of the moon (the umbra), which can extend for several thousands of miles but cannot be much wider than 167 miles in diameter.

The area of illumination for a complete lunar eclipse, on the other hand, stretches to more than half the Earth allowing billions to share in the lunar series.

2. Types

A lunar eclipse is of three types: total, partial, and penumbral. The most dramatic of these is the total lunar eclipse. It’s called the blood moon since during the eclipse the moon appears reddish.

3. Thermal Shock

When the shadow of the Earth overflows the lunar landscape, the temperature decreases dramatically. The subsequent “thermal shock” can potentially cause lunar rocks to crumble and gases to escape from within the moon. Usually, the decrease in temperature is incremental as the sun gradually sets on the surface. Yet if sunlight is cut off while the sun is up in the lunar horizon, the decrease is much faster – within just a period of 10 to 30 minutes.

Temperatures were tracked at two Apollo landing sites during a lunar total eclipse in 1971. The temperature fell from 168.3 degrees Fahrenheit (75.7 degrees Celsius) at the Apollo 12 site on the Ocean of Storms to minus 153 degrees F (minus 1021 C), a change of 321.3-degree. The temperature at the site of Apollo 14 Fra Mauro fell from 154.1 degrees F to minus 153 degrees F (67.8 degrees C to minus 102 degrees C), a change of 307.1 degrees.

4. Selenelions

When the sun and the eclipsed moon both can be seen simultaneously we get a “selenelion” or “selenehelion.” It will only happen just before sunset or just after sunrise, and both bodies will appear just above the horizon at almost opposite points in the sky.

Although the Earth is situated squarely between the sun and the eclipsed moon, so having them both in the sky is a geometrical impossibility, it is feasible since the light refraction into the Earth’s atmosphere allows all objects to look higher in the sky than their actual geometric location.

5. Different Coloured Moon

But could we mark each total lunar eclipse as a “blood moon?” Not really! It’s not clear if the moon really would appear in totality.

The reason the moon can be observed at all is that our atmosphere disperses sunlight and refracts it across the bottom of the Earth. The totally eclipsed moon ‘s colour and brightness depend on global climatic conditions and the amount of dust remaining in the air.

A clear Earth atmosphere signifies a radiant lunar eclipse. Even if a previous couple of years had seen a big volcanic explosion pump debris into the stratosphere, the eclipse became darker. Many eclipses are such a deep grey-black that the moon almost vanishes from sight or dimly glows with a brownish colour. It glows vivid orange at other eclipses, like a brand new penny.

6. Saved Christopher Columbus

When Christopher Columbus sailed into the New World, he carried with him an almanac written by Johannes Müller von Konigsberg, a great German astronomer, known by his Latin nickname, Regiomontanus. The almanac covered the 1475–1506 years. The almanac of Regiomontanus mentioned upcoming Moon eclipses.

In June 1503, on his third and final voyage in May 1502, Columbus was shipwrecked on Jamaica Island and got into trouble with the local natives who refused to provide his crew with food and water.

But Columbus also knew from Regiomontanus’ almanac that shortly after moonrise on the evening of Feb. 29, 1504, a total eclipse of the moon was predicted, so he threatened the natives with cutting off the light of the moon.

Once the eclipse progressed, the terrified natives decided to support Columbus only if he gave them back the moon.  Columbus told the colonists that the moon would reappear because he knew when totality would end. He later had no issues with the natives.

7. Hot Spots

Ironically, the eclipsed moon’s infrared images have actually shown hundreds of “hot spots” as well as large areas on the lunar surface that were hotter than their surroundings.

Scans of some influential craters, such as Tycho, seem to suggest a pattern of heat-release caused primarily by stored solar heat rather than heat from the interior of the moon, while other craters, such as Gassendi, seem to show the sort of thermal behavior one would expect from an internal heat source.

While this phenomenon has been studied for over 50 years, and many hypotheses have been put forward to explain why no one has found a conclusive explanation as to why these “hot spots” remain while the moon is completely submerged in the dark shadow of the Earth.

8. Predicts Earthquakes?

The 1971 San Fernando earthquake occurred at the foothills of the San Gabriel Mountains in Southern California on February 9. It was determined that the magnitude was 6.7. Fifteen hours later there was a complete lunar eclipse and there were some who claimed the alignment of the sun, earth, and moon was responsible for what had happened.

The director of the Griffith Park Observatory of Los Angeles, Dr. William Kaufmann stated that “Today the sun and the moon are pushing the Earth in exactly the opposite directions. As a result, the Earth is compressed into the form of a football instead of a sphere, and we assume that the gravitational forces and tidal stresses caused by this alignment are actually what triggered the earthquake.”

But in recent times there have been many complete lunar eclipses and only a few rare events have been followed by some major earthquake activity. Although the alignment between the sun, earth, and the moon can be one of the elements in triggering an earthquake, any actual relationship is highly inconclusive.

9. Foretells The End of Time?

A new word for a complete lunar eclipse has been bandied around in the mass media in recent years: “blood moon.” The phrase comes from a book written by a prophet who believed that a string of four consecutive lunar eclipses starting in April 2014 – coinciding with Jewish holidays – with six full moons in between, and no partial lunar eclipses interfering – is an indicator of the end times.

A lunar tetrad is called the eclipse sequence and is very variable with time. The Belgian astronomer, Jean Meeus, points out that there were no tetrads at all at the time when Louis XIV was king of France, but there were 16 tetrads between 1909 and 2156. And 25 of these occurred between March 16 and May 15 over a 2,000-year cycle, indicating that there were other times of history where tetrads coincided with the Jewish holidays, but nothing out of the ordinary happened. Therefore, the “Blood Moon Prophecy” is nothing more than a hoax.