Why on Earth is the planet’s day getting shorter?

By James O'Donoghue, Research Associate Professor in Planetary Astronomy, Meteorology, University of Reading

Earth will complete a rotation 1.33 milliseconds earlier than usual on Tuesday, August 5. That makes it one of the shortest days of 2025 at 86,399.99867 seconds long. How that happens, and how we can even measure it with such precision, might make your head spin faster too.

On average, Earth physically rotates in 23 hours, 56 minutes, 4 seconds and 90.5 milliseconds – this is called a sidereal day. It is Earth’s “true” rotation relative to distant objects in deep space, like stars.

However, the kind of day most people go by is 24 hours long and that is called a solar day…

Read complete article

~	Back-to-school transitions can trigger stress and anxiety — these 5 books can help

~	How language classes for immigrant students can perpetuate inequity

~	Sleepy birds, quiet dawns: how noisy, bright city nights disrupt and change birdsong

~	When it comes to weapons on Australian streets, do our perceptions match reality?

~	Belarusian hackers‘ attack on the IT infrastructure of Russia's main airline sends ‘direct message’

~	World’s biggest coral survey confirms sharp decline in Great Barrier Reef after heatwave

~	Queensland teachers are striking. It’s not just about money – they are asking for a profession worth staying in

~	Could we one day get vaccinated against the gastro bug norovirus? Here’s where scientists are at

~	The digital economy could turbocharge our productivity, but we need to get the settings right

~	Francis Bacon’s Essays explore the darker side of human nature. 400 years on, they still instruct and unnerve