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Past Shows
April 16, 2005
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Multiple Worlds, Parallel Universes
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Are there other universes out there?
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If you've ever read any science fiction, you've probably come across the idea of alternate realities: planets where life is almost the same as here on earth with just a few key differences. While the idea seems strange, it's one that some physicists are taking seriously. They're looking at the possibility other universes exist in parallel with our own.
The simplest idea is based on the fact our universe is infinitely large. According to Dr. Max Tegmark, from MIT, this means somewhere there has to be another version of the earth. Of course, that's nowhere nearby. He estimates the nearest copy of earth is at least a googleplex kilometres away. But that's far enough to be considered a different universe.
Dr. Michio Kaku, from the City University of New York, has another theory. He says our universe is like a giant soap bubble, and occasionally small bubbles break away from the edges, spawning new universes.
For Dr. Lee Smolin, from the Perimeter Institute, our universe is a parent to other universes, but not in the same way as Dr. Kaku says. He thinks universes are born and exist inside black holes. That means our universe is also the child of another universe that was similar to us, and any child universes we create could probably support life.
Dr. David Deutsch from Oxford University says the existence of parallel universes is the only way to explain certain strange quantum phenomena. He thinks every time a random event occurs the universe splits into two, creating an ever increasing number of parallel realities.
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Dinosaur Eggs
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The pelvis and egg of the dinosaur - Copyright, Science Magazine
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Finding a dinosaur is hardly a news event these days, and neither is finding a dinosaur egg. But finding an egg inside a dinosaur is something new. That’s what a team, including Dr. Darla Zelenitsky from the University of Calgary, have just described. In fact, they found two eggs in the pelvis of a female dinosaur. This extends our knowledge of dinosaur reproductive biology, and also their relationship to birds.
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Bite Club
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Skeleton of a marsupial lion - Courtesy, Government of South Australia Department for Environment and Heritage |
When it comes to sheer bite force, the now-extinct marsupial lion takes the prize as the all-time champion chomper. That is the conclusion of a new comparative study measuring the bite force of 39 living and extinct predators. The work was done in part by Dr. Jeffrey Thomason, a professor of biomedical sciences at the University of Guelph. He says it looks like a strong bite comes at the expense of a big brain. Smarter animals have better hunting strategies and don't need a killer bite. Dr. Thomason hopes this work will help answer questions about what extinct animals ate and what size prey they could take down, and help paint a picture of the hierarchy among now-extinct animals.
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Gamma Ray Extinction
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Gamma-rays strike the earth (artist's conception) - Courtesy, NASA |
We're familiar with the idea that major extinctions on earth can be caused by asteroids, volcanoes, and climate change. Now a new catastrophe has been added to the list. Dr. Adrian Melott, a professor of physics and astronomy at the University of Kansas in Lawrence, and his colleagues have determined that a major extinction 450 million years ago might have been caused by an exploding star, 6,000 light years away. This star could have created a gamma-ray burst, a ten second beam of radiation, that might have destroyed the ozone layer, and later created a global fog, leading to deaths in plants and animals from the combined effects of unfiltered UV radiation followed by an even bigger disaster as a nuclear winter-like ice age followed. Up to two-thirds of the life on earth was destroyed in this catastrophe, and they think this gamma-ray burst might have been the cause.
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