The clock that gets a big tick

QUESTION I regularly receive offers inviting me to buy a clock or watch that are ‘accurate to one second in 138 million years’. Why 138 million years?

An ATOMIC clock is the most precise timepiece. And one of the most accurate is the Caesium Fountain Atomic Clock at the national Physical Laboratory (NPL) in Teddington, Middlesex. it can measure time to an accuracy of one second in 138 million years.

it is the basis of UK time and contributes to the international time scale, Coordinated Universal Time (UTC).

radio- controlled clocks and watches get the time from UTC via a signal linked to the NPL.

Peter Smith, Durham.

QUESTION Who is the oldest person to have had a No. 1 hit?

FURTHER to the earlier answer, while Louis Armstrong lost the title of being the oldest artist to have a UK no. 1 to Sir Tom Jones, he still retains that title in the U.S. His rendition of Hello, dolly! reached no. 1 there on May 9, 1964, when Louis was 63 years and ten months old.

Mirroring her performance in the UK, Cher is also the oldest female artist to have had a no. 1 in the U.S. Believe was no. 1 from March 13 to April 10, 1999, when she was 52 years and ten months old.

in 2014, aged 88, Tony Bennett broke his own record as the oldest living artist to land a no. 1 record on the U.S. Billboard album chart with Cheek To Cheek — beating the achievement made by his no. 1 duets album in 2011.

Lawrence May, Sheffield.