From the Vaults: The Moon
The power of the internet is revealed in the things people post and repost without actually considering the source. I recently saw a post where someone cited NASA astronaut (and second human to walk on the Moon) Buzz Aldrin’s inclusion in Transformers – The Dark Side of the Moon movie (2011) as a kind of retro-proof that the Apollo Moon landings were faked. This poster seems to have missed the plot point Buzz was there to make: President Kennedy initiated the Apollo 11 landing as a cover story so NASA could explore the wreck of a Cybertonian spacecraft on the dark side of the Moon. Let me be the buzz killer here (no, I did not say ‘Let me kill Buzz’) and point out a couple of flaws in the plot if we really want to mix reality in with science fiction. First, use of the phrase ‘dark side of the Moon’ leads people to think that one side of the Moon is always dark (more on this a little later). Secondly, the Apollo 11 landing site on the ‘near side’ of the Moon would have made it virtually impossible for them to explore something on the ‘far side’ of the Moon in the time frame they were given in the movie.
Buzz Aldrin has never been shy about using his experiences as an astronaut and as one of the 12 humans to walk on the lunar surface to support his personal life. He has written books championing his ideas of how to make flights to the Moon or Mars cheaper and more efficient. Aldrin makes frequent speaking tours and talk show appearances – all have helped him forge a comfortable post-astronaut life. Can we claim to have a toy / animated movie character fashioned after and named for us (see Buzz Lightyear in Toy Story from 1995)? The real Buzz faced more ways to die on his journey to become a Moon-walker than most of us normal human beings encounter in a lifetime. I do not begrudge him earning a few bucks making a cameo in a FICTIONAL movie based on the old Hasbro Transformer toy line.
I enjoy science fiction but my science teacher brain can not help to note plot points that stretch reality to the extreme. I have learned to keep those observations to myself so no one thinks I can not suspend belief long enough to enjoy a movie. In the case of the ‘Moon landings were faked’ crowd, it is not possible to stay silent when they fold a FICTIONAL movie plot into their delusional realm of NASA / government conspiracies. Blending Sci-Fi with real-life is not a good way to prove a point – especially when there are enough facts out there to punch Titanic size holes in theories claiming we have all been duped by massive governmental fraud. Move over, Flat-Earthers, the Moon Landing Deniers are taking your spot on my list of ‘Crackpots of Scientific Discovery’.
The Moon is perhaps the most mystical of all the astronomical bodies our ancestors were able to observe. They saw the Sun on a daily basis, but it was a stable, seemingly unchanging body. Early people had no way of knowing it was a star of average age, size, and color because it is many times closer to us than all the other stars. The Moon, on the other hand, was in a constant state of change (appearance wise) as it made its way through the normal ‘Moonthly’ (monthly) cycle. When the Moon and Sun interacted during times of Lunar or Solar eclipses, it was a terrifying experience, at least until astronomers pieced together the ‘how and why’ of these celestial events. Back then, eclipse-deniers no doubt stuck with ‘a dragon is eating the Sun’ to explain what they saw but could not understand.
When Galileo was tinkering with the first practical telescope, it was hard to convince people that the Moon was another terrestrial body, much like the Earth. The church doctrine of the day stated (more or less) that all things in the cosmos were divinely created and moved about the center of the Universe (the Earth) on perfect crystalline spheres. God, they would remind all, didn’t create junk – just perfect objects that orbited the Earth. Galileo’s discovery of the four largest moons of Jupiter offered proof of the Copernican, or Sun-centered model of the Solar System. By using his telescope to support this view, Galileo was in direct violation of the church. He announced he could see valleys and mountains on the Moon with his new telescope that resembled similar features on the Earth. It certainly did not help Galileo out of the pickle he found himself in by supporting the theories of Copernicus. Copernicus had taken great pains to protect himself by seeing that his work was not published until he was no longer on this mortal coil. Galileo took no such precautions.
At some point in the deliberations with his inquisitors, Galileo had the officials who accused him of heresy look through his telescope at a familiar church across the valley. He asked them, “If you can recognize the familiar features of this cathedral magnified by my telescope, why can you not believe that the magnified terrain of the Moon is likewise familiar to features on the Earth?” They were unswayed. He escaped being burned at the stake and was instead sentenced to house arrest for the rest of his life. Galileo had friends in high places who begged him to recant which he did (sort of). He retracted his statements about the Sun-centered universe and apparently they accepted it, even though Galileo added a ‘but I am not wrong’ jibe to his retraction. Since Galileo’s time, we have studied the Moon in great detail and most school children know more about our companion than the learned churchmen of the 1600s.
Perhaps we can lean on the president of The Planetary Society, Bill Nye, to add perspective to the historical view of The Moon. In the Winter Solstice 2023 edition of The Planetary Report, Nye wrote, “First, ancient biblical authors wrote, ‘It’s as though we have two sources of light to find our way: the Sun by day and the Moon by about half of our nights.’ Then, the Moon’s gravity provides about half the attractive force that raises the ocean tides, which in turn create entire ecosystems.” Our more distant ancestors may not have realized the cumulative power of the Sun and Moon to control the ocean’s tides but maritime civilizations still charted them accurately over hundreds of years. The effects the Moon has on the oceans and on the human psyche have been observed for a long time – the latter being explained away by superstition and ‘hoo doo’. The mystery of our companion remained even after we understood the mechanics of the Earth/Moon system better than the ancients.
Nye goes on to delve further into the cultural influence of the Moon’s gravity and reflected light: “Ancient Greek observers noticed that when Earth’s shadow falls on the Moon, it’s always curved. The only object conceivable that casts a curve in any orientation is a sphere. Therefore, they realized that the Earth is round. By inference, so is the Moon. The Moon has also made us a spacefaring species. It’s as though nature provided our species with an ideal jumping-forth place to explore the Cosmos. It is always up there beckoning. As humankind took flight, the Moon became the obvious destination beyond the sky. With an enormous investment, humans walked on its surface. And indeed, new crews will be back there in just a few years.” From ancient times right up to the present, the Moon has held human minds captive.
How did we come to have a moon to begin with? Over the years, there were three main theories put forth. One was the ‘capture theory’ which held that the Moon was a wandering asteroid that was pulled into our orbit by the Earth’s gravity. This idea was dismissed with simple physics. For the Moon to have a nearly circular orbit, the speed and angle of capture would have had to be very precise. As we see with comets orbiting the Sun, a body being pulled into orbit by a larger body while traveling at a high velocity would end up with a highly elliptical orbit. The size and considerable mass of the Moon adds to the improbability of it having been captured by the Earth.
A second theory astronomers debated was labeled the ‘same time, same place’ theory. In other words, both the Earth and Moon were created together from the cloud of gas and dust orbiting the proto-star we now call the Sun. Also known as the ‘co-formation theory’, it has been largely discarded, again due to the physics of the Earth/Moon system. The angular momentum displayed by the Earth and Moon does not match up with both bodies having been accreted from the primordial materials revolving around the early Sun. The Moon also has a relatively small iron core (25 percent of its radius) compared to the Earth (50 percent) which casts further doubt on the idea of co-formation.
Other hypotheses were offered but none could check enough boxes to be considered viable. The one exception is known as the ‘giant-impact theory’ (or as I liked to tell my students, ‘the big-whack theory’). The ‘G-I’ theory places the early Earth in the path of a Mars-sized object that struck our planet with a glancing blow. When this body (called Theia) struck the Earth, it ripped material from both bodies and hurled it into space to form a disk of debris caught up in the Earth’s gravitational pull. As this disk consolidated into one mass, the compression forces generated heat that kept it a molton body for tens or possibly hundreds of millions of years. The event that began the process of lunar formation was a violent, rapid event that took only hours to occur. New evidence has reduced this initial impact timeline down from the months or years that were previously speculated. The actual accretion and cooling of this body to form the modern day Moon, however, took a much longer period of time.
How do we know this? Having taken place some 4.5 billion years ago, there obviously were no eyewitnesses to this event. We do not have a written record but we do have sufficient evidence to refine the ‘G-I’ theory. The rocks returned to Earth by the Apollo moonwalkers provided the first real proof of the Moon’s connection to the Earth. Measurements of the Moon’s oxygen isotopic ratio is nearly identical to Earth’s. Without getting too deep into the chemistry, the oxygen isotopic ratio can be measured very precisely and provide a unique and distinct signature for each body in our Solar System. This points to the majority of the material comprising the Moon as originating from the Earth.
There have always been other less obvious pieces of evidence pointing back to the Theia – Earth encounter which make more sense now. The Earth’s axis is tilted 23.5 degrees from a vertical line drawn to the Earth-Sun plane. Physics (again) dictates that planets formed from the debris disk around protostars should rotate around an axis perpendicular to that plane. Some force would be needed to upset this normal balance. Neptune, for instance, is actually laying on its side with an axis parallel to the plane of the Solar System. It would have taken an enormous ‘big-whack’ to tilt the whole planet 90 degrees. This tilt of the Earth’s axis drives the seasonal changes we see (especially noticeable in our location halfway between the Equator and North Pole). Now we know the tilt (and thus our seasons) can be attributed to the Moon’s formation.
The ‘dark side of the Moon’ issue mentioned earlier also comes from the formation of the Moon. Technically, all bodies orbiting the Sun have a ‘light side’ and a ‘dark side’. People noticed the Moon always presents the same side to the Earth but mistakenly began referring to the side we don’t see as the ‘dark side’ as if it never sees the light of day. The correct description would be the ‘far side’ of the Moon because that ‘other side’ does indeed see sunlight.
When the Moon was still a molten blob orbiting the Earth, the gravitational pull of the larger body pulled its iron core toward it. When it finally solidified, the Moon’s interior was lopsided – with the iron core being more on the Earthward side. The Earth’s gravity keeps that side of the Moon facing our way so we only see that face. In order to do this, the Moon must spin on its axis once a month meaning a day there (one spin on the axis) lasts the same as one month (the time it takes to orbit the Earth one time). Imagine holding a small child by the arms and spinning them around you – they must face you at all times even though the direction they face changes as they spin around you.
Does this mean the far side of the Moon is perpetually in darkness? Not at all. Spinning once on its axis once per month (approximately 29.5 days) means daylight and darkness lasts about 14 days across the lunar surface. When Pink Floyd’s Dark Side of the Moon album came out (March 1, 1973), the title spurred a lot of philosophical debate (“I wonder what it would be like on the dark side of the Moon, man?”). I had a standard answer: “Just like the dark side of the Earth only it would last 14 days instead of half a day!” This proved to be an unsatisfactory answer for those who wanted to believe one side of the Moon was always ‘dark’.
More recent research aided by the newest generation of Lunar orbiting space probes offers new insights about the surface we see today. When we were finally able to document the far side, the landscape (or should we say ‘moonscape’) was much different than we see on the Earth-facing side. It has now been suggested the far side of the Moon cooled more rapidly than the side facing the hot, still molton Earth. The near side crust would have hardened more slowly. The lower gravity of the Moon also affected how the lava flows spread across the surface. The image of the ‘Man in the Moon’ (or ‘Rabbit’ for our friends south of the border) is a direct result of the large basaltic lava flows that spread far and wide to create the lunar ‘seas’.
There is evidence the Moon was volcanically active up until about 50 million years ago. The early Moon may have had an atmosphere created by volcanic outgassing that was twice as dense as the current Martian atmosphere. Photos from NASA’s Lunar Reconnaissance Orbiter coupled with ground penetrating radar scans by the Japanese spacecraft Kaguya show a large pit on the lunar surface that is too deep for its width to be an impact crater. Analysis of this feature has now led investigators to a new lunar puzzle: If this feature in the Marius Hills is a skylight from a large network of lava tubes, how extensive could these caverns be? Could they be the secret to housing humans safely on the Moon? Lacking an atmosphere to protect astronauts from harmful solar radiation (as we are so protected on the Earth), could the Moon harbor life safely in underground cities?
Perhaps some will view returning to the Moon as a, “Why bother? We have already been there,” endeavor. Personally, I am excited about the next round of lunar exploration – there is still so much more we can learn from our companion. It is just too bad it has taken us fifty years to go back.
Top Piece Video: CCR at Royal Albert Hall in 1970- Bad Moon Rising of course!