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Past Shows
November 25, 2006
 Download an MP3 of the entire program (22MB) (available Saturday, two hours after broadcast).
Solar Sunscreen
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Dr. Angel's solar shields - Courtesy, UA Steward Observatory |
Global warming is upon us. It's too late to stop it by controlling our emissions -- we've already put enough greenhouse gas into the atmosphere to ensure temperature increases, and there's no indication of us slowing down. Dr. Roger Angel, a professor of Astronomy at the University of Arizona, has developed a proposal to cool the Earth by creating a solar sunshade that will block enough of the sun's rays to compensate for the warming effect from greenhouse gases. Unfortunately, it will require 16-trillion tiny spacecraft to be launched from Earth over a period of 10 years, and the development of a brand new technology for launching them. The sunshade could be deployed by 20 electromagnetic launchers launching a stack of flyers every five minutes for 10 years.
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Fruit Fly Fight Club
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Fruit Flies boxing - Courtesy, Dr. Ed Kravitz |
The humble fruit fly is a favorite species for geneticists. In the early days of genetic research they served as models to explain what happens to the body when mutations occur. More recently, the area of behaviour and genes has started to receive attention. Dr. Ed Kravitz, from the Harvard Medical School, is one researcher who's looking at behavioural genetics. The behaviour he's most interested in is aggression. When he first started working with fruit flies, not much was known about how the flies fight. Dr. Kravitz discovered that males and females use different strategies when they face off. Males lunge and flatten their opponents. Females prefer to shove and head butt when they're involved in an altercation. At the same time, Dr. Kravitz was able to uncover the genes responsible for fruit fly aggression. It turns out, they're the same genes that control courtship behaviour. Along the way, Dr. Kravitz made boy flies that fought like girls, and female flies that fought like males.
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In Praise of Older Chimps
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60-year-old Auntie Rose is still an attractive mate - Courtesy, Jean-Michel Krief |
In the human world, men prefer younger females for their mates. But among our closest living relatives, the chimpanzee, older females seem to be the ones getting all the attention. In a new study, Dr. Melissa Emery Thompson, an anthropologist and post-doctoral fellow at Harvard and Boston Universities, looked at the courtship and mating behaviour of the chimp community in Kibale National Park in Uganda. The data show that the dominant and experienced males consistently chose to mate with older females. In fact, the oldest female in the community is 60, and she's still considered more popular than the 18-year-olds. Dr. Emery Thompson says that chimps don't go through the reproductive decline leading to menopause that human females experience. Instead, female chimps are consistently fertile their entire adult lives. That might be why the males prefer them. These older females have higher quality cycles than younger females, who might not always be fertile in every cycle.
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Backing up the Planet
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Noah's Ark, by Edward Hicks. Dr. Shapiro wants to build a modern version. |
What would we do if there was a major catastrophe and large parts of the planet were destroyed? It might seem like a speculative question, but it's not without precedent. We've had disasters in the past. Large ones, like the asteroid that helped wipe out the dinosaurs; and smaller ones, like the destruction of the library of Alexandria which wiped out large swathes of western literature. Dr. Robert Shapiro, from New York University, takes this problem seriously. He and his colleagues have formed the Alliance to Rescue Civilization (ARC). ARC's goal is to make a complete backup copy of the Earth -- all biology, literature and art -- and ship it off to the moon. You could think of it as a modern-day Noah's Ark.
While ARC is still in the planning and fundraising stage, there are other, more modest projects going on around the world that address similar issues to the ones ARC is talking about.
The field of biology is concerned with conservation and preservation of species. Here in Canada there are various conservation projects. Overseeing those run by Agriculture Canada is Dr. Ken Richards. He has staff working on techniques for freezing eggs, sperm and embryos from various animals and birds. And while the techniques aren't fully developed yet, they're getting better every year. Dr. Richards also oversees governmental efforts to preserve our crop species.
Canadians are also involved in an international project that's trying to catalogue all species on the planet. It's called the Barcode of Life Database (BOLD). Sujeevan Ratnasingham is the informatics lead for the project. He says their goal is to catalogue every species within the next 20 years. Once that's complete, the database will provide a great tool for anyone who's trying to figure out what we need to save.
When it comes to archiving scientific literature, Dr. Jonathan Borwein, from Dalhousie University says the biggest stumbling block is the issue of copyright. This is hindering many projects that are trying to archive books and other textual information. Technology might not be a big issue for the digitization of literature, but it's a challenge if what you're trying to archive is art. New three-dimensional scanning techniques are being developed, though, that allow us to better preserve the structure of sculptures and artifacts.
According to Brian Porter, from the Royal Ontario Museum, even paintings can benefit from being scanned in three dimensions, since this allows the brush strokes to be preserved if the painting is lost.
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