The phenomenon of the tides is in reality found throughout the whole universe, deforming pretty much all of the celestial bodies, planets, stars and galaxies. This type of phenomenon has been observed in some cases of nearby double stars. The vivid lengthening registered in a sufficiently close pair of galaxies is explained in the same manner; it is as if they were trying to establish a bridge between themselves, and they stretch arms out on opposite sides.
The tides in the Universe
The Earth consists of two fluid masses, the atmosphere and the hydrosphere, which enclose the solid part (which as a whole presents an elasticity comparable to that of steel). Therefore, on Earth there are three species of tides; atmospheric tides, oceanic tides and tides in the solid part, which are ordinarily called terrestrial tides. In any event, the existence of atmospheric tides has never been proved conclusively.
The terrestrial tides are commonly reflected in the variations of level in some flooded mines. They are calculated by measuring the variations in the force of gravity at any given point of the terrestrial globe over time. As the Moon passes overhead, the level of the "solid" earth rises a few centimetres and then descends again.
The Earth exercises upon the Moon an attraction that is 35 times more intense than that experienced by its satellite. The action of the Sun on the Moon is negligible compared to that exercised by the Earth.
The oceanic tides affect oceans and seas and are the subject of our studies on tides4fishing.
As we know virtually nothing about the elasticity of the lunar globe, we cannot evaluate the amplitude of the deformation engendered by Earth. As the Moon always shows the same side towards Earth (it does not revolve due to the great attraction of the Earth), it is probable that this tide slightly elongates this side and also the hidden side with slight variations due to the ellipticity of the lunar orbit and the phenomenon of libration.