Earth spins more quickly
Scientists in England recorded the shortest day ever on June 29, and another shortened day on July 26.
On both of these days, the Earth did its usual 24-hour rotation in less than 24 hours. June 29 was 1.59 milliseconds shorter than usual.
The shorter days are caused by the Earth spinning faster than usual. But why is it spinning faster? Scientists have some ideas. Maybe it's the melting and freezing of glaciers, or earthquakes which move weight towards the Earth's centre.
Astronomer Fred Watson explains: "Earth is not just a solid ball that is spinning. It's got liquid on the inside, it's got liquid on the outside, and all of these things slosh around a bit."
