The Digital Press

The Earth's rotation is gradually slowing due to tidal friction, primarily caused by ocean tides, which lengthens the day by about 2.3 milliseconds per century. Additionally, ocean tides cause rapid, small changes in Earth's rotation on daily and shorter timescales, linked to tidal movements and angular momentum exchanges.

Why it matters: Earth's slowing rotation affects timekeeping, requiring leap seconds to align atomic and astronomical time.

The big picture: Ocean tidal friction drives long-term rotational braking, while tidal currents cause rapid daily variations in rotation rate.

The stakes: Accurate understanding of tidal effects is essential for precise timekeeping and navigation systems.

Commenters say: Some question the article’s math on time loss, while others recommend resources linking tides, math, and computing for deeper insight.