Everyone has that overly needy friend, the one who desperately clings to you because they’re so socially inept that they need the protection of another individual. I should know, he’s me. At the same time, that friend absorbs a constant stream of meteorite strikes that actually protect the other friend, but they still think you’re annoying even though they love you – in a way. That’s the Moon. I’m the Moon.
It will probably be in your first evening of celestial voyeurism that you end up having a look at our pale orb companion. I tried not to cover it early on because, well, it’s just there. You’ve seen it, dozens of times. Maybe not close up, but you know what it’s like. It’s a grey-white lump that just, sort of, sits about. It’s like that uncle you have who was chock full of potential but never made anything of himself (again, how my niece will end up seeing me…). You take it for granted, and for good reason, it never did anything! At the same time when you get deep into the backstory, you learn a lot and, like the object itself, the history is rather fascinating.
The Moon is Earth’s ‘satellite’, and that’s a piece of stuff orbiting a planet or minor planet. Strictly speaking the Moon is a natural satellite, to distinguish it from all the other pieces of space junk we have orbiting our planet that we put there. Those would be artificial satellites, some of which are quite useful, e.g. the International Space Station and communications or navigational satellites, and some of which are just astronaut shit. If they orbit us, they’re satellites.
Nobody quite knows how the Moon came to be there. We know it is made out of Earth-stuff, so it was likely once a part of our planet. It is speculated that sometime in Earth’s early history our planet was struck by another large object (estimated to be about the size of Venus) causing us to shed a huge weight that ended up orbiting us at a distance of about a quarter of a million miles. If you’ve ever had an appendectomy you are kindred spirits with mother Earth, although I hope the doctor you had was more tactful with the removal of your appendix than just throwing a huge mass at you in the blind hope it would knock your appendix into orbit.
It is tidally locked with us, so the face of the Moon that you look at is always the same one. It does not rotate relative to the Earth. So a new Moon (when you can’t see it in the sky) is what happens when the Earth is behind the Moon relative to the Sun. All the light hits the Moon’s backside and reflects back at the Sun, so we can’t see it. In this regard, the Moon is permanently ‘mooning’ the Sun. It’s always got its arse pointed at it. A full Moon happens when the Earth is between the Moon and Sun, the light that gets around the Earth reflects off the Moon making it very, very bright. Despite this the Moon has a low albedo. That doesn’t mean it was born without pigment, giving it pale skin and red eyes. Albedo is the measure of how reflective a celestial body is, given as a number between 0 and 1. 0 is entirely non-reflective whilst 1 would mean the object reflects 100% of the sun (or local star’s) light. The Moon has an average albedo of 0.12. Comparatively, Enceladus, the moon of Saturn, has an average albedo of 0.99.
One thing that stargazers will note about the Moon is that it is a bit like your loud friend at a party. It’s perfectly fine until its nonsense starts drowning out everything else. That it overcomes its low albedo to do this is very impressive. Essentially it overcomes its low albedo by two means. The first is that it is close to us; the second is that its albedo changes depending on its phase. So a full Moon reflects more light than a quarter Moon. During those periods of the month in which the Moon is prominent and bright, you should curb your expectations of what you can see. I have mentioned light pollution before and maybe didn’t give the Moon due respect in quite what a filthy, disgusting, light polluting chunk of discarded Earth-waste it can be.
That’s okay, though. Bright objects, particularly those on the opposite side of the sky to the Moon, are still visible. Thankfully, the Moon itself is also quite interesting to study.
Stare are an old person’s face long enough and you’ll see there are spots, blemishes, pits, craters all telling stories? No face is ever boring. They may be handsome, attractive or even drop-dead gorgeous, or they could be denizen fledglings of the ugly tree who fell and hit, if not every, at least multiple branches. Either way they are never boring to look at, as their face is a unique imprint of craters, crevices, lines and wrinkles. That is the Moon. Geologically, it’s on the explicit side of the internet – it’s got a lot going on.
Look at it through your binoculars and you will notice one of two things. If it is a full Moon you will notice that it is so bright as to be uncomfortable to look at, like snow on a sunny day. Well done, lesson learned, try again with a filter, or during a different phase. Do that and you will notice the Moon is awash with blemishes. It has small patches of virgin dust, contrasted with shadows, craters and dark patches. Every single one tells a story.
I don’t know any of these stories. But I can see huge craters that tell obvious stories of harsh impacts. It tells tales of meteorites that, maybe, could have struck the Earth causing history-altering implications, but not, because of our silvery friend. I see patches of grey and white, indicating difference and change. Nothing stays the same in this universe. Maybe it takes a long time to change, but it changes all the same. I see many smaller craters, the everyday stresses and strains of being a moon. Not quite as significant as the huge, deep, newer craters, but still from solid impacts, impacts that would have had a lasting effect. When you think about it, the Moon is a good metaphor.
Little wonder then that, culturally, it’s a muse and concubine. The silvery disc has sparked metaphor, whimsy and romantic notions in human beings for as long as we’ve been recording history and, likely, longer.
We have always related to her. I say ‘her’ because Western classical tradition contrasts the male Sun (Helios – Greek or Sol – Roman) with the female Moon (Selene or Luna).
If you understand the disregard for the feminine those cultures held you can understand it. Our potent Sun, giver of life and energy contrasted with the our impotent Moon, who only casts the reflected light of our solar, masculine magnificence and who, frankly, does little but make our nights better. In that regard, ancient astronomy and sexism have common ground – foolish disregard.
The Moon, an otherwise seemingly impotent presence, determines our tidal forces. She pulls our seas to-and-fro, causing a cyclic reaction that may soon hold the key to energy generation on an oil-lacking, damp, miserable and geologically inert island such as ours here in the UK. She provides regularity, a consistency, an efficacy to our planet that would otherwise be lacking if relying on the sun alone. We may not count our years by her, but she is our measure of months. She helps divide our time, so we may better schedule our agriculture, hence why we have harvest Moons. What is more, like any good woman in a relationship that takes her for granted, she will one day leave.
The Moon is moving away from Earth, at a rate of about four centimetres per year. This happens because the Moon gives the Earth the bulge! Phwoar! No, seriously, the tidal bulge that is created on our planet by its interaction with the moon is causing it. It’s a lot of astrophysics to do with tidal forces and gravity but the basic gist of it is the tidal bulge tries to pull the Moon and speed up its orbit, whilst the Moon pulls back and slows down the Earth’s rotation. The upshot of this interaction is the Moon gets further from us, and our days get longer. One day she will likely leave us entirely. The thought that our distant relatives will one day gaze up at the sky (during their – due to the gravitational effects of having no Moon – slightly longer nights) and see no Moon gives me a good reason to enjoy it whilst it can be seen.
It would take an estimated fifty billion years for the Moon to reach its maximum orbit, thus reaching the point where it could gain freedom from Earth. At that point, though, both the Moon and the Earth will be evaporate and space-ash having been consumed in the final, angry, existential whims of that fearful fireball, our sun. Not to make you worried about your Greatx108 grandchildren, but our Sun only has about another 4.5 billion years left in it. Regardless, whilst her influence may never fully diminish, she will get further away, she will grow more distant.
She can be boorish and bossy. Sometimes she stops us seeing others who we might like to see and sometimes she casts such a bright light over our lives that she seems overbearing. Like all great broken loves, though, one day humans – or the species evolved from us – will gaze at the sky and tell stories of the one who got away. The one who once so captured our imaginations that we wrote songs and poems about her, yearned for her, even made her a goddess, before we had even reached out our grubby, unworthy hands and touched her fair surface. When we did, at last, reach her, it was a magnificent crowning glory. The awakening, the coming of age, of an adolescent species once glued to its home left touching naught but itself.
One day we will pine for the love who once made a glistening romantic dream of our otherwise bland, dark nights. So when she stops you seeing other things in the sky, remember not to take her for granted. Our pale love, the pock-skinned protector, carrier of light to our otherwise black nights, sweet Selene, will not be so close to us forever.