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Ray Jayawardhana: Waiting for a Supernova

  • Uploaded by thinkbig on Jan 3, 2014
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The poltergeists of physics. That is how scientists refer to neutrinos, the elementary particles that zip through our bodies and morph into different forms like "cosmic chameleons evading capture." Neutrinos are also said to be "pathologically shy" in that they rarely interact with other particles. And yet, it is said that whenever anything cool happens in the universe, neutrinos are usually gigantic supernova explosion would qualify as a cool cosmic event. Neutrinos, which travel at nearly the speed of light, would bring this information to us. Let's say that a massive star dies on the far side of the Milky Way galaxy. We might not see this event with our optical telescopes because stellar dust obscures the visible light. However, the neutrinos would still get through. "Because these particles don't interact with much they can escape from the site of mayhem -- basically from the core of the explosion unhindered and reach us and therefore confirm directly what's going on there."So says Ray Jayawardhana, an astrophysicist at the University of Toronto and the author of Neutrino Hunters: The Thrilling Chase for a Ghostly Particle to Unlock the Secrets of the Universe ().In the video below, Jayawardhana explains how neutrino astronomy began in 1987 when three different neutrino detectors around the world suddenly detected two dozen neutrino. These particles carried information from a massive explosion in a nearby dwarf galaxy. This allowed scientists for the first time "to confirm the physics of what happens when a star explodes at the end of its life," Jayawardhana supernova SN 1987A was the nearest exploding star that we have known about in some 400 years -- "pretty much since the invention of the telescope," Jayawardhana says. "So that made it a big deal." Now Jayawardhana and other physicists are hoping to catch a glimpse of a supernova explosion in our galaxy. Nobody knows exactly when this might occur, but thanks to the development of massive neutrino detectors, we would have an "unprecedented peek at the action."Finding exploding stars in the far reaches of the galaxy is merely one of the possible applications of neutrino research. Jayawardhana says that neutrinos could also help us to measure Earth's internal heat, as well as understand how matter won over antimatter after the Big Bang. Other creative, and even outlandish ideas have also been proposed such as using neutrino detectors to expose the nuclear capabilities of rogue nations and using neutrino signals for equity trading. Transcript --Neutrinos are a type of elementary particle. In fact, they're the most common type of matter particle but they don't interact very much with the environment. That means they're hard to pin down. So as we're sitting here trillions of these particles are zipping through our bodies and there's nothing we can do about it. And there's a small chance -- maybe 25 percent chance that over the course of a person's lifetime there'll be one interaction of one neutrino with an atom in your body but luckily these particles don't cause any harm and they don't leave any trace as they pass through our bodies right through the Earth and vast distances across the universe. So they really are ghostly elusive bits of matter that are produced often when nuclear reactions happen -- for example, in the core of the Sun or in a nuclear reactor on Earth as well as when a massive star explodes at the end of its lifetime as a gigantic supernova explosion. Back in 1987 this massive star exploded at the end of its life in a satellite galaxy of the Milky Way. And when that happened astronomers starting with a couple of observers based in Chile happened to notice this star suddenly brighten pretty much overnight. And they realized that something was going on and indeed it continued to brighten and was quickly recognized as a supernova explosion, the nearest one that we know about in some 400 years -- pretty much since the invention of the telescope. So that made it a big deal. And yet it was not quite in our galaxy and our neutrino detectors back in 1987 were just sensitive enough that three different neutrino detectors around the world registered a total of a couple of dozen by Jonathan Fowler, Daniel Honan and Dillon Fitton



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