The nights sky has fascinated humankind for millennia. It instills a sense of wonder in our curious minds and provides us all with a great deal of perspective as to how small our entire human existence really is in the greater scheme of things. The enormity of what lies out there is difficult for us to truly comprehend, even for those who have spent some dedicated time in studying the universe. Of all things far out there, the moon is the closest celestial object of significance to Earth and sits a mere 384 000 km away! For some perspective, travelling at a maximum vehicle highway speed of 120km/h (75mph) non-stop, it would still take you 4 months and 10 days to arrive at the moon! Yet just last week, the 20th of July, commemorated 50 years since man first first set foot on the moon, a momentous moment for humankind. I was reminded of this event on the day through a few posts across social media and, since then have been paying some extra attention to our marvelous moon as it slowly wanes away this past week. This prompted me to flick back into my notes and do some reading up on the moon, its many wonders and colossal impacts it has over the Earth.
Contrary to what most people may think, the moon is in fact black in colour; covered by a layer of illmenite mineral. The pearly white appearance that we are all so familiar with is simply the suns light shining back towards us off the extremely reflective illmenite. With the naked eye, and even more so through a decent pair of binoculars, several craters can been seen on its surface. These craters are created by meteorites colliding with the moon over time and have been perfectly preserved in the motionless state of the moons ‘atmosphere’ (or lack thereof) – much the same way that Neil Armstrong’s footprints will still be found unchanged around the land site of Apollo 11 today. The craters visible from Earth will always be the exact same craters as only one face of the Moon is ever seen from Earth. This is because the Moon rotates around on its own axis in exactly the same time it takes to orbit the Earth, meaning the same side is always facing the Earth.
Due to the fact that there is no atmosphere on the moon, a few things change on the surface. Firstly, temperatures on the moon can change rapidly and widely. The daytime temperature generally sits at a boiling 105 degrees Celsius (220 degrees Fahrenheit) and can easily drop to -150 degrees Celsius (-240 degrees Fahrenheit)! The lack of atmosphere also means that the ‘sky’ always appears black from the moon as there is no substance around to refract the suns light before reaching the moons surface.
We view the moon in a different state each night as it slowly waxes and wanes from new moon to full moon and back again. This process of one new moon to the next takes roughly 29.5 days and is known as a lunar month. While our Gregorian calendar’s months are slightly longer, its roots were initially established by ancient civilizations which based their calendar on the cycles of the moon. Given the lunar month is marginally shorter than our Gregorian month, we witness a ‘blue moon’ roughly every two and a half years where there are two full moons in a calendar month (and no, the moon doesn’t actually turn blue!). The next blue moon will be in October of 2020.
With the moon being an ever-present object in the night sky, it is quite easy to overlook. But as we slowly approach yet another full moon on the 15th of August, take a few moments to gaze up at it each night and slowly watch the illumination spread across its surface. It can be quite be humbling in giving some perspective as to how small we really are.