Buzz
In ancient Roman culture, Luna was revered as the goddess of the moon. Often portrayed in art, she would steer her chariot, drawn by horses or oxen, across the sky. The Romans embraced the Greek goddess Selena, who was similarly shown in her chariot and represented by a crescent moon. According to Greek legend, Selena would shoot an arrow filled with stars across the sky at dusk every evening.
Not everyone knows this, but our celestial companion actually has a proper name, and it isn't just 'moon'—a term that is far too generic. 'Moon' refers to any large object in a permanent orbit around a planet, and lacks the personality you'd expect from such a unique celestial body.
True to the tradition of naming celestial bodies after figures in Roman mythology, scientists named our Moon 'Luna.' This is fitting, as 'Luna' is the Latin, Italian, and Spanish word for 'moon.'
Luna is a fascinating, enigmatic orb and stands out as a remarkable celestial object in our solar system. While it's not the largest moon (that honor belongs to Ganymede), it is the largest moon relative to its host planet, Earth, which is more significant. After all, Ganymede seems tiny when compared to Jupiter, while Luna is a quarter of the size of Earth. Keep reading for more amazing facts about our superstar moon, Luna. And don’t worry—we’ll clarify the 'biggest' moon topic a little later...
Could Our Moon Be Hollow?
On November 20, 1969, after safely returning to the Apollo 12 Command Module, Lunar Module pilot Allan Bean and Commander Charles Conrad Jr. sent the now obsolete lunar lander (LEM) crashing into the Moon's surface. This deliberate crash was part of an experiment designed to collect seismic data, using the seismometer the astronauts had installed on the Moon’s surface.
The impact was successful, landing within the necessary range for optimal seismic readings. The astronauts were undoubtedly pleased at first, but their excitement soon turned to disbelief when they heard the Moon resonate like a bell for nearly an hour. The data seemed to suggest that the Moon might be hollow, or at least partially so.
NASA repeated the experiment on subsequent missions with identical results, but this time they struck the Moon even harder. The result was more dramatic: the Moon didn’t just echo like a bell; it rang like a gong for over three hours, with reverberations reaching as deep as 20 miles (32 kilometers).
This discovery was troubling for planetary scientists, as it contradicted all four existing theories on the Moon’s origins. Yet, the data from NASA was indisputable. The findings have left experts to grapple with questions that challenge our understanding of the Moon's composition and history, though we are still far from fully understanding the implications.
The Moon Is the Largest Satellite Relative to Its Planet in the Solar System
The Sun's diameter is approximately 400 times that of the Moon, and it just so happens to be about 400 times farther from the Moon than the Moon is from Earth. This unique alignment allows Earth to be the only planet in our solar system that can experience total solar and lunar eclipses, as no other moon is both large enough and close enough to its host planet to create such a phenomenon.
With a diameter of 2,160 miles (3,476 kilometers), the Moon's size is crucial to the occurrence of total eclipses. If its size were just a little smaller or larger, complete eclipses of the Sun or Moon would not be possible. The Moon's proximity to Earth and its almost perfectly circular orbit are essential to our planet’s stable rotation and tides, as well as the magnetic field that protects life on Earth.
Not only is the Moon the fifth largest moon in the solar system by size, but it also holds the title of the largest moon relative to its host planet. Even the massive Ganymede appears small compared to Jupiter, yet the Moon is a quarter of Earth's size. This unique size and distance relationship between the Moon and Earth is what allows us to witness both total lunar and solar eclipses, underscoring the Moon’s vital role in sustaining life on Earth.
Scientists Worry the Lunar Lander Will Become Stuck in Lunar Dust
This topic could have easily been a headline in the 1960s, as scientists estimated that over 4.5 million years, a significant amount of moon dust would have accumulated on the lunar surface. Some even speculated that it could be enough to engulf the lunar lander entirely.
Based on a 1960 estimate of 14.3 million tons (12.9 billion kilograms) of meteoric dust falling to Earth annually, some researchers suggested that the thin layer of dust on the Moon's surface points to the youth of the Moon—and by extension, the Earth and the solar system. Before the moon landings, there were also fears that astronauts could sink into a thick layer of dust. However, the scientific community has yet to explain why the expected dust buildup was not found.
When Apollo 11's lunar lander descended on July 20, 1969, its engine kicked up a cloud of dust. However, upon landing, only a few centimeters of dust were displaced, revealing the solid bedrock underneath. Contrary to earlier concerns, the Moon was not covered by 60 feet (18 meters) of dust waiting to engulf the spacecraft and its crew. The astronauts were safe.
The Moon Is Slowly Drifting Away
After the Apollo missions returned to Earth, scientists embarked on a long-term experiment to periodically measure the distance between Earth and the Moon. These measurements revealed that the Moon is slowly moving away from Earth at a rate of 1.5 inches (3.8 cm) each year. This has been tracked thanks to three sets of retro-reflectors placed on the lunar surface by Apollo crews.
At the National Radio Astronomy Observatory (NRAO), scientists utilize a powerful laser to direct a beam at one of the reflector stations on the Moon. By measuring how long it takes for the beam to travel to the reflector and back, and performing some calculations, they can accurately determine how much the Moon has moved away from Earth since the previous measurement. While this phenomenon was predicted, the rate at which it's occurring has surprised scientists. NASA explains that 'Milankovitch cycles' are responsible.
Milankovitch cycles are tiny changes in Earth's orbit that affect the amount of sunlight our planet receives as it orbits the Sun. These cycles can also impact the distance between Earth and the Moon. While more research is needed, scientists understand that the tidal changes resulting from the Moon's recession could have negative consequences for Earth.
For instance, industries like fishing and shipping would lose significant advantages if the Moon moved too far from Earth. These industries, along with most others, rely on the Moon’s tidal forces to aid in the faster transport of goods that are crucial to global trade. This is just one example of a negative economic effect, but the broader impact would be catastrophic for all life on Earth. Problems would arise almost immediately, and within months, life would struggle to survive.
However, there's no need to be concerned, as this won't happen for eons... unless...?
Astronauts Couldn’t See Stars, but They Saw Fireflies
On July 20, 1969, with Michael Collins orbiting the Moon in the Apollo 11 Command Module while Neil Armstrong and Buzz Aldrin walked on the lunar surface, humanity achieved the monumental feat of visiting another celestial body. Though the astronauts appeared lively and cheerful during their post-moonwalk press conference, behind closed doors, a strange and unsettling phenomenon was casting a shadow over this historic accomplishment. Astronauts later referred to this eerie experience as 'fireflies.'
Reflecting on his time in space, Michael Collins openly shared his feelings of regret in an interview. Describing his encounter with an odd event, he pondered, 'The phenomenon prompted a series of covert experiments, but could the explanation be from another world?' He added, 'In 1969, the first men on the Moon were hailed as heroes, yet when Buzz Aldrin discussed strange flashes of light in the spacecraft’s cabin during the debrief, it raised more questions.'
Collins further revealed that months later, astronaut Alan Bean experienced something even more unusual. Bean admitted to observing flashes of light while on the Moon’s surface. 'The first time I saw them,' Bean recalled, 'I was on the far side of the Moon, gazing at a crater when I saw a flash.' He confessed, 'I thought to myself, “Did I really see that?” because nothing should have been happening down there.'
Dr. Story Musgrave, a renowned NASA space shuttle pilot and former astronaut, compared the phenomenon to fireworks. 'It’s like the Fourth of July,' he said, describing the lights. 'They streak—they’re fireworks.' This evocative description eventually led to the phenomenon being named 'fireflies.'
5. The Moon Has a Shape Resembling a Lemon
A recent study published in the renowned journal Nature suggests that Earth's immense gravitational force played a crucial role in shaping the Moon into its current lemon-like form. Some scientists propose that the Moon may have originated from debris ejected into space following a massive impact with Earth around 4.5 billion years ago.
It's important to note that the giant impact hypothesis is only one of four competing theories explaining the Moon's formation. The other three theories—capture, condensation, and fission—each come with their own set of unresolved issues and unique challenges.
As outlined in the Nature study, it's widely accepted that Earth's gravitational pull influenced the Moon's early development. This process led to tidal bulges on the Moon's surface, contributing to the geological features we see today. Additionally, Earth's gravity is believed to have caused the Moon’s crust to thin at the poles while thickening at the equator, giving it its distinctive lemon shape.
4. Transient Lunar Phenomena
Strange lights on the Moon have been observed by astronomers, both amateur and professional, for centuries. Known as transient lunar phenomena (TLP), these mysterious occurrences remain unsolved. For over a thousand years, observers have reported lights in colors like orange, red, pink, and green on the lunar surface. It wasn't until the 1960s that the scientific community began to take these ancient reports seriously, prompting astronomers to investigate the phenomenon of 'lights on the Moon.'
Since then, more than 2,200 documented instances of the transient lunar light phenomena have been recorded throughout history. Modern astronomers have officially verified over 300 sightings of these mysterious lights on the Moon. One of the earliest reports dates back to June 18, 1178, when five monks from Canterbury witnessed a 'flaming torch' shortly after sunset in the Moon's northern region, emitting fire, hot coals, and sparks over a significant distance. Even the renowned British astronomer Sir William Herschel observed three glowing red spots in a dark part of the Moon, which he believed were caused by volcanic activity.
In an interesting twist, the aurora borealis was shining brightly over Padua, Italy, which is an extremely rare occurrence. This was just under 1,000 miles away from Sir William Herschel, at the same time that the sun's sunspot activity was at its peak.
3. The Title Says, “Earth’s Biggest Moon,” But There’s Only One!
Is Earth’s biggest moon a myth? Well, not exactly. While we all know that Earth has just one moon, astronomers have long speculated that there may be two other objects orbiting Earth. According to findings published in the Monthly Notices of the Royal Astronomical Society, these moons are made up entirely of fine dust particles, which don’t reflect light well and are therefore hard to observe. Their discovery took much longer than expected, despite being nearly the same distance from Earth as the Moon—approximately 248,548 miles (400,000 kilometers).
The two additional moons were first identified 62 years ago by Polish scientist Kazimierz Kordylewski in 1961. Initially dubbed the Kordylewski Dust Clouds (KDCs) rather than moons, they were not universally accepted as solid objects. However, a recent study used a polarized filter on photographic equipment, which concentrated light and captured clearer images, confirming their existence. Now, with three moons, not one, circling our planet, we just need to come up with names for them. Any suggestions?
2. Lunar Dust is a Terrible Trouble
The Moon’s surface is nearly completely covered by a substance known as lunar regolith, a fine, dark gray powder that is almost as smooth as wheat flour. There’s so much of it that the Moon’s bedrock is only visible on the steep, inclined walls of craters.
Lunar regolith forms quite differently from regolith found on Earth or Mars. On Earth and Mars, regolith is essentially dirt that undergoes erosion from wind or water, but lunar regolith is formed by millions of micrometeorite impacts, which create razor-sharp shards that never weather, staying sharp. Over time, it only gets finer as it’s constantly bombarded by cosmic debris, but it retains its sharp edges.
These are the reasons lunar regolith posed so many challenges for the Apollo astronauts. It was as fine as flour, as sharp as glass, and it attracted static electricity, causing it to stick to everything. Its abrasiveness and spreadability led astronauts and ground control to worry it could damage a space suit, which could be fatal. The astronauts also reported that the regolith stuck to their suits, spread throughout the lander, got into their eyes, causing irritation, and into their lungs, causing coughing.
1. NASA Seriously Considered Nuking the Moon
In 1958, the Soviet Union launched Sputnik 1, the world's first satellite to orbit the Earth. Despite its minuscule size, its primary function was to send a weak radio signal saying, “I’m still alive,” and that was all. This simple device caused immense fear in the American public, as it symbolized the possibility of the Soviets gaining the ability to launch space-based nuclear attacks. The notion of such a power in the hands of the Soviets terrified many, fueling Cold War anxieties.
To regain an advantage in the nuclear arms race, the United States Air Force devised a plan known as Project A119. It was based on a study titled 'A Study of Lunar Research Flights,' which aimed to explore the potential impact of detonating a nuclear device on the Moon. Led by NASA physicist Leonard Reiffel, the project was designed to understand the effects and visibility of such an explosion on the lunar surface.
Reiffel, from the outset of Project A119, believed that the true motives behind the plan were politically driven. In a 2000 interview with The Observer, he stated, 'It was clear the main aim of the proposed detonation was a PR [public relations] exercise and a show of one-up-man-ship [over the Soviets].'
Essentially, the Air Force envisioned creating a massive mushroom cloud on the Moon’s surface, visible to all of Earth, as a demonstration of American technological prowess. Thankfully, more rational voices prevailed, ensuring that this project never came to fruition and leaving space exploration to be defined by missions like Apollo and the historic Moon landings.
