tidal

Tidal describes phenomena related to tides and the gravitational interactions among the Earth, Moon, and Sun. In a broad sense, tides are the regular rise and fall of sea levels and the associated movement of water masses, driven mainly by gravity and the rotation of the Earth. The term is also used in related contexts, such as tidal currents, tidal energy, and tidal locking.

Causes and mechanisms: Tides arise from the differential gravitational force exerted by the Moon and Sun across the Earth. The side of Earth nearest the Moon experiences a stronger pull, creating a bulge, while the far side experiences a weaker pull and forms another bulge due to inertia. The rotation of the Earth keeps these bulges aligned with the Moon, producing regular high and low tides. The Sun, although much farther away, is also influential; its gravity enhances or diminishes tides depending on the relative positions of the Sun and Moon.

Patterns and terminology: Tidal behavior varies with coastlines and seabed geometry. Common patterns include semidiurnal tides (two high tides and two low tides each day), diurnal tides (one high and one low per day), and mixed tides (a combination of the two). When the Sun, Moon, and Earth align during full or new moon phases, spring tides produce higher highs and lower lows; when they are at right angles during quarter moons, neap tides yield smaller tidal ranges.

Impacts and uses: Tides shape coastal ecosystems, affect navigation, and drive tidal energy projects that harvest power from tidal streams or barrages. Tidal locking, a related concept, occurs when a body's rotation period matches its orbital period, as seen with the Moon’s orbit around Earth.