Dark Side of the MoonPink Floyd’s album, is the cause of an astronomical misunderstanding. There is no dark side to the Moon, any more than there is to Earth. The Moon always shows the same face towards our planet, and the reason for this is usually attributed to a hasty equality between the time of rotation and the time of revolution of our satellite. There is a synchronous rotation, that is, it is true that the Moon orbits the Earth in the same time it takes to rotate itself. The interesting thing is to understand how we arrived at this result.
The Taurids and Leonids will grace the night sky this November.
It all starts with the tides
Newton’s law describes the gravity of two bodies orbiting each other as “points” with all their mass concentrated in the center. We know that celestial bodies are not points, but lumpy spheres of inhomogeneous mass, swollen at the equator and flattened at the poles. When one body orbits another, the mutual gravitational attraction is stronger than on the opposite side, in this case the Earth. This simple fact triggers the tides: when the Moon is on one side of the earth, it draws the mass of water towards it more to one side, and therefore, the level rises and there is a high tide.
However, on the opposite side of the Earth there is no low tide for a simple reason: the Moon not only attracts more water, but also rocks, so the entire Earth deforms in its direction; while the opposite side experiences less gravity, and is therefore less attracted. The result is two protuberances: one near the Moon and another on the opposite side, while the rest of the planet is at low tide. That’s why every day, in every place in the world, there are two low tides and two high tides.
#Moon #show #face
