Good News: The Day Is Getting Longer. Bad News: By 1.33 Milliseconds a Century.
Ever feel like the days are dragging on longer? Turns out you’re right — scientifically. Earth’s rotation is slowing, which means each day is getting very, very slightly longer. Before you celebrate the extra time, it’s measured in milliseconds. But the why is a perfect little lesson in how tiny things compound.
Aylin Woodward · The Wall Street Journal · May 30-31, 2026 · Capital Wealth analysis by Sean Anees Saifi
Like a skater pulling her arms in, Earth spins down.
The Figure-Skater Effect
We think of a day as exactly 24 hours, but precise measurements show that’s not quite true. Over the past two decades, day length has grown by about 1.33 milliseconds per century, according to a study in the Journal of Geophysical Research. The Earth is, very slowly, spinning down.
The culprit is melting ice. As temperatures warm, ice in the Arctic, Greenland, and Antarctica melts, and that water shifts away from the poles and out into the oceans. Think of a figure skater in a spin: pull your arms in and you spin faster; extend them and you slow down. Moving Earth’s ‘mass’ away from its axis is the planet extending its arms.
Why Anyone Cares About a Millisecond
A millisecond sounds like nothing, but our entire modern world runs on absurdly precise timekeeping. GPS, navigation apps, satellites, and financial-trading timestamps all depend on clocks that agree down to fractions of a second. When the planet’s spin drifts, the keepers of official time occasionally have to fiddle with ‘leap seconds’ to keep everything in sync. Small number, big plumbing.
What This Means For Your Money
Here’s the gentle investing point hiding in a science story: tiny changes compound into enormous ones if you give them enough time. A millisecond per century sounds like a rounding error. So does the difference between a fund that charges 0.05% and one that charges 1.0%. So does an extra 1% saved each year. Stretch any of those over a working lifetime and the gap becomes the difference between comfortable and constrained.
The planet is teaching the same lesson your 401(k) does: the forces that feel too small to matter today are often the only ones that matter in the end.
