Post #7
Moon Madness
The moon is a touchy subject in my family. Even mention of the word "moon" can make the conversation heated. My mother made a rule to not discuss the moon at dinner because it never ends well for anyone.
My dad and I are at a war of sorts. He is firm in his belief that we see the whole moon and not just the one side. He is a sturborn Dutch guy in his 60's and will not change his mind even with science and facts to prove him wrong. He is set in his ways.
I've tried to explain that we only see one half of the moon's surface, and never will expeience the other half-sphere with our eyes from the Earth. I've drawn diagrams and send him links to articles and videos with explanations. I point the moon out to him some nights, and remind his that it's the same moon he saw the last time I pointed it out. But he refuses to even consider looking at the facts and admitting he is wrong. Maybe it's just personal.
Last night I was struggling to come up with ideas for this blog today, and I asked my parents what they think I should maybe blog about. My dad chuckled for a minute, and jokingly said "The moon". So you know what, dad? Here I am.
To begin, I woul like to say that the moon is not stuck in one place with one side facing us. The moon also rotates while it orbits Earth, and the time it takes for the moon to revolve on its axis is about the same as it takes the moon to orbit Earth, about 27 days or about a month. One full "day" on the moon is about 4-Earth weeks long. If the moon didn't rotate at all, we would see all of the moon as it orbits Earth, not just one side.
The moon is tidaly locked to the Earth, which is why it rotates at such an exact speed and why we only see one side. The Moon’s gravity pulls on the earth, and the water on the surface of the Earth closest to the moon responds by elongating towards the moon. The water on other parts of the earth feels the Moon’s gravitational pull as weaker, with the water on the opposite side of the earth feeling the weakest pull. However, these tidal forces also have another effect - they resist rotation.
When the moon first formed, it was certainly moving at a faster speed, and not tidaly locked. But eventually, due to the gravitational pull of Earth, and the moon's resistance to that pull, the moon had slowed and no longer rotated faster than it was orbiting Earth. Once the Moon’s rotation had slowed so much that a single half was always facing the surface of the Earth (about 4 billion years ago), it had officially been tidally locked, and has stayed so ever since.
The opposite effect influences Earth also. The pull of the moon and the resistance of Earth against that pull. But the moon is much less massive and it's effect on Earth takes longer to impact our spin time. But it is measurable, and apparently is slowing down the rotation of the Earth by about 15 microseconds every year, in turn, lengthening our days.
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