Jumat, 21 Juni 2024

June 22: Listener Question Show - CBC.ca

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 Question show, 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.

A bright moon is seen against the dark blue background of the sky between two dark outlines of high-rise buildings.
The supermoon rises over the Queens borough of New York. If the Moon was much closer to our planet than its current distance of over 300,000 kilometres, it would take up a significantly bigger spot in the night’s sky. (John Minchillo/The Associated Press)

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.

Five sheep stand on an inclined rocky surface with green pines in the background.
In some animal species where courtship requires fighting for a mate, having prominent physical features, such as large horns, can prove to be an evolutionary advantage. (Jet Belgraver/CBC News )

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. 

A man with brown hair and a grey-white beard looks off camera at an awards ceremony where he's wearing a fancy jacket with his bare chest adorned with necklaces underneath.
Rufus Wainwright's hair at the 66th GRAMMY Awards in February, 2024 demonstrates how the hair on different body parts can turn grey before others. (Monica Schipper/Getty Images/The Recording Academy)

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.

A rocky mountain range, with snow-capped peaks, is shown beneath a blue sky.
Tall mountain ranges like the Himalayas, pictured here, are formed when two continental plates collide, says Alexander Peace. (Monika Deupala/File Photo/Reuters)

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.

A whitetail doe and her fawn keep an eye out from a field.
Fear of predators can lead prey animals like wild deer to eat less and produce fewer offspring, says wildlife ecologist Liana Zanette. (Robert F. Bukaty/The Associated Press)

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.

An aerial view of a half-moon shaped dam holding water back on the bottom of the photo, with the turbulent water seen in the middle of the photo, and a cityscape seen around it.
Hydro generating stations like this one on the Chaudière Falls near Ottawa are great at making clean power but don't change the temperature of the water - and so wouldn't be useful at cooling the oceans to solve global warming. (THE CANADIAN PRESS/Adrian Wyld)

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.

An orange butterfly is perched on some small pink flowers.
Native plants have evolved along native wildlife and as such play essential roles as both a food source and habitat. An example is the milkweed plant, which is the only host plant for monarch butterflies and monarch caterpillars. (Douglas W. Tallamy/Timber Press via AP)

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.

On a royal blue background, we see a fuzzy circular object in the centre with a bright red dense nucleus and aqua blue rings around it to show where the electron wave / particles are located.
Physicists used a 'quantum microscope' in 2013 to peer inside a hydrogen atom to show the 'electron cloud' rings around the nucleus. (A. S. Stodolna/Physical Review Letters)

Debbie Turner in Fenelon Falls, Ontario asks: 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. 

A snow-dusted brown bear crawls out from underneath a pile of snow.
Warmer winters bring less snow, which means less snow cover for the hibernating animals. University of Saskatchewan associate professor Jeffrey Lane says this can lead to the animals having to expend more energy to warm themselves up for the lack of the natural snow 'blanket.' (Kaisa Siren/AFP via Getty Images)

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. 

On the top image, we see big planets in orbit around a sun. In the bottom image, we see the planets of our solar system in stylistic depiction of them orbiting around our sun.
In our solar system, the only planet large enough to exert a significant gravitation pull on our sun is Jupiter. The diameters of the sun and the planet orbits are not to the same scale. (Kirk Woellert/NSF)

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2024-06-21 18:20:16Z
CBMiTWh0dHBzOi8vd3d3LmNiYy5jYS9yYWRpby9xdWlya3MvcXVpcmtzLXF1YXJrcy1xdWVzdGlvbi1zaG93LWp1bmUtMjItMS43MjM4NTI00gEgaHR0cHM6Ly93d3cuY2JjLmNhL2FtcC8xLjcyMzg1MjQ

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