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Past Shows
February 10, 2007
 Download an MP3 of the entire program (22MB) (available Saturday, two hours after broadcast).
Watching the Northern Lights
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The Northern Lights - CBC image |
Canada's a great country to watch the Northern Lights from. It's a great place for scientific study of them, too. Especially in Alberta, where researchers at the University of Alberta and the University of Calgary have built up expertise in studying the aurora borealis. Now, that expertise is being tapped by NASA as part of the THEMIS mission. THEMIS, or Time History of Events and Macroscale Interactions during Substorms, is a project that's going to use five satellites and twenty ground-based monitoring stations to watch the development of the aurora. They're hoping to figure out what triggers substorms. These are massive releases of energy in the atmosphere that lead to the brightest displays of the Northern Lights. Dr. Ian Mann, a professor of physics at the University of Alberta, is part of the team working on THEMIS.
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Stopping Light
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Courtesy, S. Garner and Nature Magazine |
In the past few years, physicists have learned some interesting ways to manipulate light. They've shown they can make it appear to speed up, bend and even slow down to a crawl. But, all that was outdone this week by Dr. Lene Vestergaard Hau, a professor of physics and applied physics at Harvard University. Not only is she able to slow light down, but she has figured out how to stop it dead in its tracks, turn off, and start back up again in a new spot. While the experiments are still at an early stage, Dr. Hau thinks this could revolutionize computing in the future.
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Molecular Condom
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From liquid to gel and back again, could this prevent HIV? - Courtesy, Julian Fabian, University of Utah |
Microbicides are one of the great hopes for preventing the spread of HIV in Africa. They're women-controlled methods of prevention that generally involve application of an anti-viral liquid to the reproductive tract. However, the products being tested now have some severe limitations. One major problem is they need to be applied directly before sexual activity. Dr. Patrick Kiser, an assistant professor of bioengineering at the University of Utah, is part of a team that thinks they've come up with a better solution. They've created a substance that starts out liquid, turns to a gel once it's applied, and then turns back into liquid when it comes in contact with sperm. This would allow the material to be applied hours in advance of sexual activity, and then release anti-viral drugs when they're needed the most.
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Sandblasting Moon
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Enceladus - Courtesy, NASA |
Saturn's moon Enceladus is an interesting satellite for a number of reasons. It's a solid ball of ice, and the most reflective object in the solar system. It's also geologically very active. The inside seems to contain liquid water, which escapes through geysers at the moon's south pole. The moon is also responsible for the creation of one of Saturn's rings. The 'E' ring is made up of ice particles that have been released from Enceladus. Now, Dr. Anne Verbiscer, a professor of Astronomy at the University of Virginia, has shown these particles are affecting other moons of Saturn. By measuring the various moons' brightness, she's figured out that these ice particles are falling on the surface of the moons, and basically sandblasting them. As the particles land, they stir up the surface, making it fluffy, and bright from here on earth.
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Hidden Secrets on the Y Chromosome
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Human chromosomes |
The Y chromosome, which is passed down from father to son, can be used to look back thousands of years into a man’s ancient family history - as well as give us clues about human migratory history. And it was while studying the relationship between the Y chromosome and family names of a large group of British men, that Turi King uncovered some surprising DNA in a typical Yorkshireman. His family name was a very old, very rare and local Yorkshire name, Revis. But, his type of Y chromosome had, until now, only ever been found in Africa. The gentleman never knew of any African ancestry and carries no physical traits that would reveal this part of his family history. The first Africans arrived in Britain as Roman soldiers, but Ms. King's guess is that this particular DNA stems back to the time of the slave trade in the 1600s and 1700s. Ms. King is a Canadian researcher, who’s doing her PhD at the University of Leicester. She says this kind of genetics not only radically broadens the concept of family history, it also raises questions about the meaning of race.
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Question of the Week: Baby Teeth and Wisdom Teeth
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This question comes from Wally Kiel and Bob Holden in Vancouver. They ask: If humans are born with baby teeth, which are later replaced with permanent teeth, is this the case with other mammals as well? And why do most human adults have to have their wisdom teeth removed?
For the answer, we go to Dr. Joy Richman, who’s a professor of pediatric dentistry at the University of British Columbia.
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