Tidevannskrefter

Tidevannskrefter, or tidal forces, are gravitational forces that cause tides. They arise because the gravitational pull of a celestial body, most commonly the Moon and the Sun on Earth, is not uniform across the entire body. The side of Earth facing the Moon experiences a stronger gravitational pull than the center of the Earth, and the center experiences a stronger pull than the far side. This differential pull stretches the Earth along the line connecting it to the Moon.

This stretching creates bulges of water on both the side of Earth facing the Moon and the opposite side. As the Earth rotates, different locations pass through these bulges, experiencing high tide. In the areas between the bulges, the water level is lower, resulting in low tide. The Sun also exerts tidal forces on Earth, but due to its much greater distance, its effect is about half that of the Moon. When the Sun and Moon are aligned, their tidal forces combine, leading to exceptionally high spring tides. When they are at right angles to each other, their forces partially cancel out, resulting in weaker neap tides.

Tidal forces are not limited to oceans; they affect the solid Earth and the atmosphere as well, albeit to a lesser extent. The concept of tidal forces is also relevant in astrophysics, explaining phenomena like tidal locking, where one side of a celestial body perpetually faces another, and tidal disruption events, where massive objects are torn apart by the gravitational pull of a black hole.