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From Gérard Petit, Time Section, Bureau International des Poids et Mesures

It’s amazing that a small bug in one particular GPS receiver with few, if any, practical consequences is mentioned in a Â鶹´«Ã½ feature about measuring time (22 November, p 30).

I would like to correct some points. The responsibility for establishing international atomic time from some 200 atomic clocks worldwide rests with the Bureau International des Poids et Mesures, and not the International Telecommunication Union. The ITU is only the regulatory body that established the procedure for adding or removing leap seconds in the 1970s.

In recent years there have been a lot of discussions about the future of universal coordinated time (UTC), culminating in the meeting in Turin mentioned in the article. But, the only question submitted to the audience for a show of hands was: “Do you think the present system is adequate for the next 30 to 50 years?” Though the verdict was no, the majority for this was quite small.

The advantages of making a change are not clear. First, any change that is not backed up by a strong technical rationale is likely to create more havoc than it corrects, as the latest software bug shows. Secondly, the great majority of problems with the present system are caused by errors or intentional intervention by humans, and this will remain true even with perfect regulations.

Sèvres, France