The GuardianThe Guardian

Oh my days! Midnight comes a fraction sooner as Earth spins faster

By Ian Sample

01 Aug 2022 · 3 min read

Editor's Note

Did you know that when dinosaurs roamed the Earth a day was only 19 hours long? This piece explains how and why our the length of our days fluctuate.

If time feels tighter than ever of late, blame it on the revolution. On 29 June this year, Earth racked up an unusual record: its shortest day since the 1960s, when scientists began measuring the planet’s rotation with high-precision atomic clocks.

Broadly speaking, Earth completes one full turn on its axis every 24 hours. That single spin marks out a day and drives the cycle of sunrise and sunset that has shaped patterns of life for billions of years. But the curtains fell early on 29 June, with midnight arriving 1.59 milliseconds sooner than expected.

Sign in to informed

  • Curated articles from premium publishers, ad-free
  • Concise Daily Briefs with quick-read summaries
  • Read, listen, save for later, or enjoy offline
  • Enjoy personalized content