Why does a cornea heal and cartilage wears out, when neither has a blood supply?
Why does a cornea heal and cartilage wears out, when neither has a blood supply? MARK R SLACK, VIA EMAIL The outer layer of the cornea is called the epithelium. It is made up of cells that are constantly turned over, as the outermost cells are shed into the tear film. Corneal abrasions usually affect […]
Why do dogs like sticks so much?
Why do dogs like sticks so much? SARAH HARTLEY, DEVON What’s brown and sticky? Hurray for sticks; nature’s very own dog toy. Not only are they free, they’re also readily available, biodegradable and fun for our four-legged friends who like to fetch, gnaw and parade around with them. For some pooches, the stick’s allure may […]
Nature’s weirdest animals: The coelacanth
NATURE’S WEIRDEST ANIMALS… The coelacanth For years, scientists thought it died out with the dinosaurs. The only known coelacanths were fossils. Then in 1938, a South African museum curator found a dead one in a fisherman’s catch. Live specimens were later caught, proving that this curious fish was never actually exinct. Living deep in the […]
How do volcanic eruptions affect climate change?
How do volcanic eruptions affect climate change? DAVID SCOTT, PORT ST MARY, ISLE OF MAN Explosive eruptions can cause substantial cooling of global surface temperatures, lasting for anywhere between 1 to 10 years. We have known about this cooling for centuries, with our temperature records often showing distinct dips following major eruptions. One of the […]
If the Moon were bigger, at what point would it be deemed a planet and the Earth and ‘Moon’ a ‘binary planet’ system?
If the Moon were bigger, at what point would it be deemed a planet and the Earth and ‘Moon’ a ‘binary planet’ system? DERRYCK MORTON, POUGHILL, DEVON The criteria which distinguish between a ‘binary planet’ (or ‘double planet’) and a ‘planet-moon system’ (or ‘planet-satellite system’) are, unfortunately, not well defined. An obvious criterion is the […]
Do houseplants actually improve air quality?
Do houseplants actually improve air quality? SAM NICHOLLS, VIA EMAIL Most of us have been spending a lot more time at home these past couple of years – prompting us to ask questions about the quality of the indoor air we breathe. Pre-COVID reports show that Brits spend more than 90 per cent of our […]
How are atolls formed?
How are atolls formed? SUZIE SCOTT, EDINBURGH Atolls are ring-shaped coral reef islands in the open ocean with a central lagoon. They’re found in warm, tropical or subtropical waters where corals can flourish. Of the 439 atolls in the world, most are located in the Pacific Ocean. Atolls have vibrant ecosystems, and the parts of […]
Dear doctor…
ILLUSTRATION: DANIEL BRIGHT
Do any other animals get insomnia?
Do any other animals get insomnia? JENNY EDWARDS, VIA EMAIL Other animals display insomnia-like behaviour. For example, in a seminal study it was found that when male rats were rehomed from their individual cages into those of other male rats, they displayed what resembled stress-induced insomnia. Furthermore, ‘insomnia-like flies’ take longer than others to fall […]
Why do bullets make a zing sound in movies?
Why do bullets make a zing sound in movies? PAUL FROM NC, VIA EMAIL Bullets from real guns only ‘zing’ if they ricochet off something hard at a fairly shallow angle. This causes them to tumble very rapidly and the turbulence of this motion as they fly off sounds like a high pitched whine that […]