August 10, 2019 — The Quirks & Quarks Listener Question show
Does climate change cause earthquakes? Why is it blurry underwater? Do animals do math? And more
Originally published on January 4, 2019.
To start the new year we present another edition of our ever-popular Listener Question Show, where we find the experts to answer your questions.
Renata Ruffell from Victoria, B.C., asks: "After hearing about the increase in natural disasters, I am now wondering: are earthquakes impacted by climate change?"
Alison Malcolm, an NSERC Chevron Industrial Research Chair in the earth sciences department at the Memorial University of Newfoundland in St. John's, explains that any time you move mass around on the Earth, there is the possibility that earthquakes will result.
Melting ice caps change the forces on the land under the ice, which can in turn cause seismic activity. Climate change-related sea-level rise can also change the seismicity patterns. Events like increased rainfall, or even drought, also reduce or increase forces acting on the Earth, and these are predicted to come with global warming.
Take heart though, because this is not likely to lead to huge city-destroying earthquakes, but to more subtle and smaller local seismic disturbances.
Derek Wilson from Port Moody, B.C., asks: "Recently, I read the memoir of the late Canadian author and naturalist Farley Mowat titled The Dog Who Wouldn't Be. In it, he talked about how as a child, he was puzzled by the behaviour of his great horned owl, who liked to disturb an anthill and then 'dust' himself with the infuriated ants. Mowat admitted he couldn't think of an explanation for this behaviour. Neither can I. Can you explain the owl's unusual behaviour?"
Jason Weir, an associate professor in the department of biological sciences at the University of Toronto, says this is a well know phenomenon observed in more than 200 species of birds, and is known as "anting."
There's no definitive answer to why birds do this, but researchers speculate that one possible reason is that the birds are using the attacking ants to rid themselves of pests. The angry ants squirt their defensive acid at the birds. This doesn't bother the birds, and may kill or drive off parasites like ticks or mites that infest the birds' feathers.
Roger Corey from Edmonton asks: "I know that the moon Enceladus sprays water into space constantly. Wouldn't this, over time, cause the moon to disintegrate into nothing as it blasts all its material into space?"
Yanqin Wu, a professor of astronomy at the University of Toronto explains that the reason Enceladus, a small moon of Saturn, sprays water into space is a deep mystery. Its -200 C degree surface temperature means it really should be solid ice. It may be that the interior of the ice moon is kept liquid by the tug of Saturn's gravity.
Researchers think that the source of the water is an underground salt-water ocean. Enceladus sprays out an estimated 200 kilograms of water per second, and may have been doing so for billions of years. At that rate it is very likely Enceladus will evaporate itself away if it continues to spray water into space in just another few billion years.
Michael Bishop from Ottawa asked: "Why does vision get blurry underwater?"
Scott Reid, an associate professor in the department of biology at the University of British Columbia, says it all has to do with how light bends as it passes through the transparent cornea and lens of the eye, which work together to focus light on the retina.
Light bends when it transitions from one medium to another. So when it goes from air to the denser cornea it bends to focus on the retina. When we go underwater, the cornea stops functioning: it no longer bends light because the density of the cornea is very close to that of water.
Michael Clague from Vancouver asks: "Last spring, I broke my right tibia. It was a clean break. My question is, if there's no physical connection between the parts of the bone, how do the ends of a broken bone find each other?"
Diane Nam, an orthopedic surgeon and scientist at Sunnybrook Health Science Centre in Toronto, explains that the distance between the bones has to be a very small gap — a few millimetres — in order for the two pieces to rejoin again.
The overall alignment of the bone is what's important. As long as it's pointing the right way, then it will reconnect correctly during the healing process. Over time, bone cells will deposit calcium that bridges from one side to the next, and the cells will then remodel the new bone to be as strong or stronger than it was before. If the gap between the broken parts is too large or is displaced, then surgery may be necessary to realign the bone.
Sean Chapman of Ottawa asks: "We know that a climate catastrophe led to the rise of the dinosaurs. Any guesses what species would gain dominance now?"
Jessica Theodor, a professor of biological sciences at the University of Calgary explains that the rise of the dinosaurs came at what is called "the great dying," which was a result of huge amounts of volcanism at the end of the Permian Extinction 250 million years ago. If such a climate catastrophe were to occur today, the first organisms to recover would be weedy plants and animals — things that can live in variable and disturbed environments.
Which plants and animals would come to dominate the planet might depend on whether or not humans have survived. If we did, animals that live well with or around us, like rats, raccoons, dogs, pigeons and crows would likely do well. If humans do not survive, it is difficult to guess what else would thrive, but life has come back from severe setbacks in the past.
Margaret Bell from Corunna, Ont., asks: "As an engineer, I wonder about the design of wind turbines. I have noticed only one specific design represented in all the turbines I have seen. Is there really only one best design for all locations?"
David Wood, Schulich Chair in Renewable Energy from the department of mechanical and manufacturing engineering at the University of Calgary, says that most common wind turbine designs include a large tower with the three-bladed propeller.
Industry has converged on this as the most efficient design for a number of complicated reasons, though there is large variation in the size of these turbines, with the largest offshore wind turbines having blades measuring up to 90 metres in length. New designs for application in water, including current and tidal turbines, are in the experimental stage. This includes quite different designs like the vertical axis turbine, or "egg-beater" design.
Harry Liston from Ottawa asks: "I would be interested in knowing how much calculating animals are capable of. Since figuring out the odds of an encounter would drastically improve the rate of survival, would not even a rudimentary mathematical skill give a huge evolutionary advantage to wolves in a pack for example?"
John Fryxell, the executive director of the Biodiversity Institute of Ontario at the University of Guelph, explains that animals can be trained to evaluate the number of objects with some accuracy, especially if there is a food reward.
But generally, animals in the wild, like wolves in a pack, can measure relative magnitude in terms of ratio, rather than actual counting when it comes to an encounter with prey or predators. This is also true of primates and some birds. Humans also do better at assessing ratio or proportions rather than actual numbers.
Suzi Inkman from Harrison Hot Springs, B.C., asks: "After a long day of hiking, we all had sore legs. Two days after, my legs were still sore. Why do muscles feel sore after exercise? And why do they stay sore for so long?"
Michael Connor, an associate professor in the school of kinesiology and health science at York University, says the experience of muscle soreness a few days after exercising is known as "delayed onset muscle soreness."
It's a common experience when you're trying a new form of exercise or when you're increasing the intensity your regular workout. By overworking your muscles you can cause individual muscle fibres within the larger muscle to tear, which leads to pain in the moment or later due to inflammation. There may also be damage to connective tissue, and painful spasm as the muscle repairs itself.
The torn fibres regrow stronger than before, which is why pain can sometimes lead to gain.
Jim Haycock from Ottawa asks: "Every space science fiction movie I have ever seen has a spinning space station to simulate gravity to keep the astronauts healthier. How come our space stations aren't spinning with this in mind?"
Krishna Kumar, a professor in the department of aerospace engineering at Ryerson University, explains that a spinning space station is unfeasible due to engineering and economic barriers.
In order to simulate one G, the force of gravity on Earth, you'd need to spin a two-kilometre long station at one rotation per minute, and we don't know how to design, let alone pay for such a station.