A heavy metal clock that is accurate to one second in 20 billion years – longer than the age of the known universe – is being planned by German physicists.
They hope to create a nuclear clock that works not by counting the regular swings of a pendulum nor the tick-tocking of a springloaded ratchet and not even the energy changes taking place in an atom of caesiu, but rather by observing the changing properties of the tiny nucleus at the heart of an atom of thorium. Specifically, the short-lived state of that element known as 229mTh, technically known as the isomeric first excited state. The team recently detected this state setting them on the road to building their nuclear clock. I highlighted the press release about this research a couple of weeks ago.
But, of course, children playing in the garden have known for a long, long time how to tell the time most accurately, thanks to the delicate seed heads of Taraxacum officinale…
