Moon – The one and only natural satellite of Earth, is 4.6 billion year old hovers above us, bright and round until it seemingly disappears for a few nights. It is the fifth-largest natural satellite in the solar system and apparently, the rhythm of the phases of the Moon had guided humanity for millennia.
Now imagine, what if there was no Moon? Will everything be the way it is? The answer is – No. We might face a number of consequences like:
And most importantly, Moon is responsible for slowing down the Earth’s rotation through tidal interactions. If there was no Moon, Earth would have been spinning at a faster pace and as a result, our day would probably only be about 6 hours long! Besides, the fast rotation results in faster winds and stronger storms which will also affect the plant photosynthesis, animal hunting, and even our sleep cycle.
A day on the Earth is approximately 24 hours long, but this was not the case millions of years ago. The Earth was spinning or might have spun really fast when it was in its infancy. With the presence of Moon, the rotation of the earth slowed down, but only by a few microseconds every year which can be noticed if we look at the bigger picture.
It will take around 4 million years for us to get rid of the leap year. And if we are given enough time (which comes around billions of years), we can actually witness the earth getting tidally locked to the moon, the same way the moon is with the planet Earth. It implies that the Moon will be visible only to the half of the planet, and the other half will have to travel to the other side of the globe to see it. But in reality, this event will not occur because the Sun would have long died before this event would even take place.
If we use the rate at which the earth is slowing down and calculate the rate at which it would have been spinning for billion years ago, we can say that it was spinning at around 3-4 times as fast it does right now! That explains the above-mentioned fact- that our days would have been much shorter. It implies that due to the high rate of spinning would have resulted in having 1000 days in a year and the Earth would have had a larger equatorial bulge and flatter at poles.
Going back to what we learned
In our textbooks, we have learned that the Earth rotates on its axis, tilted at around 23.5 degrees relative to its orbital plane which doesn’t change much over time compared to other planets in our solar system. Take a look at the case of Mars, it had a tilt which could vary anywhere from 15 degrees to around 35 degrees. This tilt plays a vital role in the planet’s climate. The changes in season that we experience are because of this tilt and the Moon stabilizes it. It is because of the immense gravitational torque exerted mostly by the Moon and the Sun on the Earth that the shift in the axial tilt is between 23-26 degrees.
If we had no moon, the earth would have been like planet Mercury. This would have resulted in no seasons, making every place on the planet have practically the same climate. Or else the tilt of the axis would have been so severe that Earth would actually rotate on its side like planet Uranus which is rotating on its side resulting in really long summers and winters. That is indeed a tough place to survive!
Though moon is relatively smaller as compared to Earth, it impacts us immensely and contributes towards our planet’s sustainability. Now we know that even something so far away from us can play such an important role in our daily lives and the planet we live on.
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