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This week’s new questions

Why don’t moons have moons? How much of a dog or cat’s food intake is used to maintain their fur coats?

27 May 2026

KENILWORTH, ENGLAND - OCTOBER 18: (EXCLUSIVE COVERAGE) Winner of Best In Show Household Pet, Luci, a red tabby and white Persian cat is seen in a studio portrait during the GCCF Supreme Show at Stoneleigh Park on October 18, 2025 in Kenilworth, England. (Photo by Shirlaine Forrest/Getty Images)

Shirlaine Forrest/Getty Images

What percentage of a dog or cat’s food intake is used just to maintain their fur coats?

Richard Hughes
Leckhampstead, Buckinghamshire, UK

 

2GEDA0C BRNO, Czech Republic - August, 14. 2020 Giant inflatable model of the planets Mars, Earth and Moon at night with silhouettes of people. Solar system

Jiri Hojda/Alamy

Stars are orbited by planets, and planets by moons. So why are there no moons with natural satellites of their own?

Richard Grimmer
Trowbridge, Wiltshire, UK

 

Last Word is ¿ìè¶ÌÊÓÆµ’s long-running series in which readers give scientific answers to each other’s questions, ranging from the minutiae of everyday life to absurd astronomical hypotheticals. To answer a question or ask a new one, email lastword@newscientist.comTo 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.

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