June 22: Listener Question Show

Quirks and Quarks54:00Listener Question show

To wrap up the 48th season of Quirks & Quarks, we've got another edition of our ever-popular Listener Questionshow, where experts provide answers to your burning science questions.

Christ Kennedy from Moncton, New Brunswick asks: If someone had the means to, how close could we bring the Moon to the Earth while still keeping it in orbit around us? And fast would a month fly by?

Brett Gladman, a professor of astronomy at the University of British Columbia, says bringing the Moon closer to the Earth would result in many fascinating changes. It could circle our planet in 6 hours instead of 27 days; it would rise in the west and set in the east; and the tides would become so drastic that ocean waters would scour the entire land surface of the Earth several times a day. Gladman says we don't have to worry about this, however, as the Moon's orbit has been steadily expanding over the past millions of years.

Matoli Degroot from Manitoba asks: Do animal species in the wild get bigger over time, since the bigger males would end up mating more than the smaller ones?

For the answer, we reached out to Danielle Fraser, who is the head of paleobiology at the Canadian Museum of Nature in Ottawa. She says that while some animals get bigger over time as a result of sexual selection, not all animals compete for mates by fighting, where body size can be an advantage think of birds and their elaborate plumage and mating dances. Fraser says the environment and food availability also play a role in determining body size.

Bill Sullivan from Hamilton, Ontario asks: Why does the hair on my head turn grey while hair on the rest of my body does not change colour?

To untangle this question, we spoke with Frida Lona-Durazo, a postdoctoral fellow of computational genetics at the University of Montreal who's studied the genetics of hair colour. She said we go grey when our pigment stem cells go defunct as we age and one theory for why that may differ on your scalp versus the rest of your body is due to the speed at which the hair on the scalp grows. How our cells are making proteins from our DNA can differ in various body regions and environmental factors, such as some drugs, HIV or stress can prematurely grey some areas but not others.

Dan from Quebec City asks: We know that the Earth's crust is built of plates that float on the molten centre of the Earth. What is the force that moves those plates?

For the answer, we reached Alexander Peace, an assistant professor in the School of Earth, Environment and Society at McMaster University in Hamilton, Ont. He explained that the movement of tectonic plates on the Earth's mantle is governed by their composition: oceanic plates tend to be denser while continental crust is more buoyant. When two continental plates collide, the force of the collision pushes them up to form mountain ranges, while a meeting of the denser oceanic crust and a more buoyant continental plate forces the heavier oceanic plate under the continent, forming a subduction zone.

Frances Mawson from Heckmans Island in Nova Scotia asks: Prey animals like deer are intermittently forced to flee from various predators. When danger has passed, they pause for a moment and then resume browsing. How can they recover so quickly?

We asked wildlife ecologist and Western University professor Liana Zanette, who studies the ecology of fear, to shed light on this topic. She said that while the animals may appear calm, fear of predators has a great impact on their life: they spend less time grazing and more time on high alert, which causes them to eat less and in the long run, produce fewer offspring. And since humans are the scariest predator for most prey animals, Zanette suggests being mindful of the effects of your presence on the local wildlife during your nature hikes.

Richard Lukes from Winnipeg asks: As a hydro generating station generates energy, what is the effect on the downstream water? Has the temperature of the water been lowered? If so, then could hydropower help to cool the oceans and combat global warming?

We got the answer from Jaime Wong, an Assistant Professor in the Faculty of Mechanical Engineering at the University of Alberta. He says that hydro generating stations get their energy from the gravitational force of the water falling through a turbine, so the temperature hasn't changed, and thermal energy isn't something we could tap to cool the oceans.

Luc in Edmonton asks: With more people planting native grasses and plants around their houses and businesses in cities, will the bird population in these cities change or increase?

For the answer, we turned to Sheila Colla, an Associate Professor in the Faculty of Environmental & Urban Change at York University and York Research Chair in Interdisciplinary Conservation Science. She says that because birds and insects evolved alongside our native plants, they have relationships with these plants to provide food and habitat. Since bird populations have been in decline, planting native plants will help support native wildlife much better than imported or invasive species of flora.

John Ugyan from Kelowna, British Columbia asks: If atoms are 99.99% empty, why do our eyes see matter as if it was 100% solid?

We asked condensed matter physicist, Cissy Suen who's a joint PhD student from University of British Columbia's Quantum Matter Institute and the Max Planck Institute for Solid State Research in Germany, who said the electron space around the nucleus of atoms isn't actually empty. We see matter as solid due to the wave nature of the light that our eyes take in.

Debbie Turner in Fenelon Falls, Ontarioasks: How does climate change affect animals that hibernate?

We got the answer from Jeffrey Lane, an associate professor in the department of biology at the University of Saskatchewan. He says the changing climate is affecting all of the critical periods in a hibernating animal's life: warmer seasons may mean they go into hibernation later and emerge from it sooner, while the period of hibernation itself may be getting shorter if the animals' "natural blanket" of snow cover melts sooner or doesn't accumulate during higher winter temperatures.

Greg Hollinger from Owen Sound, Ontario asks: Since the planets orbit the sun in a plane, does their combined gravity pull on and distort the shape of the sun?

We went to Roan Haggar, a postdoctoral fellow at the University of Waterloo's Centre for Astrophysics, to get to the bottom of this stellar question. He said when it comes to the influence the planets have on the sun, the only planet that matters is Jupiter. Its gravitational pull may not distort our sun, but it does make it wobble a wee bit.