If Earth had no moon, do you think we would know anything about tidal forces?
The daily tides in Earth’s oceans are caused by the gravitational effect of the Moon and the Sun, which raise tidal bulges in the hydrosphere. The tidal effect of the Moon is almost twice that of the Sun. [ The size of the tides depends on the orientations of the Sun and the Moon relative to Earth. A differential gravitational force is always called a tidal force, even when no oceans or even planets are involved. The tidal interaction between Earth and the Moon is causing Earth’s spin to slow.
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