South Pole Physics: Ice Cube and the South Pole Telescope
The South Pole is home to two of the most powerful telescopes on Earth: Ice Cube and the South Pole Telescope. Neither look at visible light. Both are studying the origin of the Universe, but in very different ways. The Ice Cube project (http://icecube.wisc.edu) detects neutrinos — invisible high-energy particles that can only be detected when they interact with the deep, dark ice below the Pole, producing a blue light. The South Pole Telescope (http://pole.uchicago.edu) investigates Dark Energy and takes snapshots of the Cosmic Microwave Background Radiation to determine what the Universe looked like 13.7 billion years ago.
Read excerpts of meteorologist Dan Satterfield’s blog post below to learn how the Ice Cube telescope works. In addition, Dan has created two short videos to describe each of the projects. Dan’s videos and Earth Gauge photos are included here. All are available for download.
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Tour of the Ice Cube neutrino observatory at the South Pole. Dan Satterfield video. |
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Interview and tour with South Pole Telescope scientists. Dan Satterfield video. |
The Strangest Telescope on Earth: Ice Cube, by Dan Satterfield
Imagine a particle so small that it could pass through the entire Earth and not run into anything. That particle exists and it is called a neutrino. It has no charge and very little mass. There are a lot of them around. Many trillions pass through you every second but they don’t hit anything either. So why use a telescope to detect them and why do astronomers care?
… Neutrinos have a big advantage over other things we build telescopes to see. They travel in a straight line and they ignore everything they pass through! We cannot see through our Milky Way Galaxy because of clouds of dust. Neutrinos pass right through with no affect. They can pass through almost anything with little or no affect.
… Cosmic rays hitting the atmosphere produce the lower energy neutrinos and our sun produces the trillions per second [high energy neutrinos] that pass through us. Astronomers are most interested in the high energy neutrinos. Those produced in supernova explosions, or the ones coming from the Big Bang when the universe was about two seconds old.
So what happens when a neutrino does hit something? It produces another particle that continues in exactly the same direction and it produces a flash of blue light! That we can see. To detect them and trace where they come from, you need to block out as many of the low energy neighborhood neutrinos as possible, and you need a nice dark place full of something for the neutrino to hit, that is clear so we can see them … How about a one kilometer cube of ice, one kilometer below the South Pole?
It is being constructed now. Scientists are digging holes around 2,500 meters deep and installing an array of detectors on a series of lines dropped into the hole. They dig the holes using heated water. Once they place the sensors, called DOM’s (Digital Optical Modules), they will be frozen in the ice for thousands of years. A whole array of these DOM’s will be used to track the blue light produced by those very unlucky neutrinos that do happen to hit something …
Read the full blog post.
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Huge hoses “drill” holes thousands of feet deep by blasting hot water into the ice sheet at the Ice Cube site. Photo by Ann Posegate. |
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A drill hole at the Ice Cube project. A string of Digital Optical Modules (DOMs — neutrino detectors) are lowered into each hole and left to freeze in the ice, where they will remain for thousands of years. Photo by Ann Posegate. |
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A Digital Optical Module (DOM) signed by Dan Satterfield, Ann Posegate and other media visitors. Photo by Ann Posegate. |
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Two strings of DOMs at a previous drill site, now frozen in the ice sheet. Photo by Ann Posegate. |
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The South Pole Telescope. Photo by Ann Posegate. |
