91É«ÇéƬ

I enjoy diving into the sea for fun. Might whales, sharks and rays breach just because it feels good?

Rod Kater,

Allynbrook, New South Wales, Australia

As Earth’s rotation slows, how long will it be before the rules for deciding on leap years have to be revised?

Goronwy Humphreys,

Wallasey, Cheshire, UK

To answer this question – or ask a new one – email lastword@newscientist.com.

Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address.

91É«ÇéƬ retains total editorial control over the published content and reserves all rights to reuse question and answer material that has been submitted by readers in any medium or in any format.

Terms and conditions apply.