Our timeless fascination with Selene runs so deep that we romanticise her splendid appearance, we marvel at her gracefulness and her beauty, and some even worship the power she beholds upon us all, inhabitants of her celestial companion, Earth. Selene, better known as Luna – the Latin name of our beloved Moon – has always been a source of wonder for poets and astronomers alike. Once a month, she unveils in complete candidness her resplendent visage, shining upon our vales, cities and seas, her silvery glow. Then, over the course of a fortnight, she will gradually go into hiding, shy and prude. But the cycle continues when, from the darkness, she emerges once again perhaps just above the horizon or high above the forest canopy, and teases us with a glimpse of her face anew.
Luna embraces us not only in sentiment but also physically, through the medium of gravitational attraction. Her effect on our oceans is most noticeable as the tides ebb and flow under her spell but she also plays a much more important yet invisible role. She is a crucial stabilising factor of Earth’s rotation. Without her, Earth would wobble as it spins upon itself causing its axis of rotation to shift so drastically over time. This shift in Earth’s tilt would inevitably induce tremendous alterations in Earth’s seasons – much more prominent than what we currently experience. Thankfully, the Moon is here to maintain a relatively constant tilt of Earth’s axis of rotation.
It is a quirk of nature that the relative positions and sizes of the Sun-Earth-Moon system are such that, when viewed from Earth, the Sun and the Moon appear to be discs of nearly equal diameter. In fact, so similar are their apparent sizes that when the conditions are just right, the jealous Moon would glide across the sky and position herself in such a way as to obstruct our view of the majestic Sun. But this phenomenon doesn’t last for more than a few minutes and occurs once every 1.5 years. Such a total solar eclipse is a truly mesmerizing sight.
Sometimes, though, it is the Earth that places itself between the Sun and the Moon. When this happens, the Earth casts a shadow upon the Moon’s surface. This shadow grows bigger and bigger the more aligned the Moon-Earth-Sun system becomes. At its most perfect alignment, the Moon is completely submerged in the darkness but she doesn’t disappear from view. Not happy to be shunned into obscurity, Selene enrobes herself in gorgeous red attire, attracting our stunned gazes unto her eclipsed self. The lady in red will then pose in the soft light of a thousand sunsets and a thousand sunrises as the rays from the Sun refract through Earth’s atmosphere, causing this reddish glow to fall upon and caress her rounded figure. Just like a solar eclipse, such a magnificent sight doesn’t last for too long. The recent total lunar eclipse we have just witnessed has been termed a rare event. Fear not for the next one is due on the 8th of October this year. The Moon will once again be the centre of attention as she puts on her red dress for another show. Ironically then, once in a blue moon, she will wear red – so to speak.
This celestial dance of the Moon-Earth-Sun system is all held in place through gravity but this near-perfect overlapping of the apparent sizes of the Moon and the Sun will not last forever. As the Moon gradually recedes from the Earth – at a rate of about 2 cm a year – there will come a time when Luna will no longer completely cover up the Sun during a solar eclipse. Granted it will not be so tiny as to resemble the transit of Venus – a mere dot, a puny pimple on the face of the Sun – but it will no longer be the same magical experience for us. But maybe this wouldn’t matter. Perhaps by then we would have left our home planet and settled on a different world, where another Selene would watch over us…