Bonzer Words!: The Moon — Our Sister World
“Every year it recedes 2 inches further away from us,’’ writes Wendy Ogbourne in this introduction to our sister world, the Moon.. “Originally it was 10 times closer to earth—what a sight that would have been!’’
Our Moon holds a special place in our lives. Ancient peoples talked of the moon as a goddess, and writers have linked her through the ages with beauty and romance. Some can see a face—the Man in the Moon—though other cultures see different things: a woman, a hare, a frog, a mouse, or a buffalo. The dark patches that look like eyes, nose, mouth etc., are impact craters made by space debris bombarding the surface, and old volcanic action from within the moon itself.
But what is the moon and where did it come from? It is a satellite—a celestial body orbiting around a planet, our earth. Because it rotates at the same speed as its orbit, the same face is always turned towards us, and no human being had ever seen the far side of the moon until photos taken by a lunar probe in 1959. It is a rocky world, with no atmosphere, and its gravity is only 17% that of earth. It has no water, so cannot support life. It is approx 384,000 km from earth, and 3500 km in diameter, about one quarter the size of earth. Every year it recedes 2 inches further away from us. Originally it was 10 times closer to earth—what a sight that would have been!
There have been several theories as to how the moon was formed. One suggested that it was a smaller sister planet formed at the same time as earth. Another that it was a small piece of earth that spun off at a time when the earth was rotating much more rapidly. Perhaps it was a small asteroid, which was captured by earth's gravity. However, since astronomers have been able to measure the composition of the moon's rocks, they have decided that a small body hit the earth while it was still forming. This blew off some material from earth which combined with the intruder and formed the moon, which was then unable to escape back into space and was captured for ever.
Although small in size, the moon's gravitational pull is the cause of our tides. The water in the seas directly underneath the moon is pulled up into a bulge. As the earth rotates, that bulge moves around. At full moon and new moon, there are especially high tides, because the sun, moon and earth are lined up, increasing the gravitational effect. These are called 'spring tides', but the name has no connection with the spring season—only that the water was thought to 'spring' or 'leap' upwards. At other times, they are weaker and are called 'neap tides'.
Everyone knows the saying 'once in a blue moon', meaning 'hardly ever'. But is there ever really a blue moon? On rare occasions, the moon can appear bluish, due to dust particles in the atmosphere, such as after bushfires or volcanic eruptions. The term 'blue moon' is also used to refer to the few times when two full moons occur in any calendar month. This only happens once every two and a half years.
People sometimes say jokingly that the moon is made of green cheese. The first reference to this comment was in 1546, but it's not likely that even then, anyone truly believed it. It's now only used sarcastically, to suggest something ridiculous, on a par with 'pigs might fly!'
A full moon in spring is known to be the trigger for the mass spawning of corals in the seas. No-one quite understands how this happens, but it is an incredible event to witness.
But the full moon has also been credited with more sinister effects on human beings. The word 'lunacy' comes from the same Latin root as the word 'lunar'. Europe in the Middle Ages was rife with folk legends of men turning into werewolves overnight, terrifying the populace. Many still believe that there is an increase in everything from natural disasters, crime, suicide, mental illness, road accidents to the fertility rate at the time of the full moon. Though there have been many surveys showing no statistical confirmation that any of these things actually occur, full moon madness hype is now a staple for our media in all forms, and will continue to be so, despite the evidence.
So far, the moon is the only extraterrestrial body that humans have visited. We love her. She belongs to us. Ever changing, yet always the same. The light in our darkness.
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Wendy writes for Bonzer! magazine. Please visit www.bonzer.org.au
