Measuring time using the Earth’s rotation was always an imprecise business, so now we do it using the ‘tick’ of an atom

Amazing answers to your curious questions

It’s time for an upgrade… so Chris Rowlands clocks in with a selection of top tickers for counting the hours in style

Q What are some of the longest lifespans in fish? A Technically the longest lifespan lies with the Greenland shark, which live a staggering 250-plus years – perhaps even more than 500, in some cases.

Whether you strap a wellness coach to your wrist or weave subtle sensors into your clothes, these devices are revolutionising how we track our health

Although it’s by no means certain, scientists are slowly accumulating evidence that life once existed on the Red Planet