Synopsis:

To view neutrinos from distant explosions, astrophysicists have set up thousands of detectors in pure ice at the South Pole. What are neutrinos, and what do these scientists hope to learning from them?

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Illustration: The Why Files

IceCube sees both cosmic rays and neutrinos from the Southern-Hemisphere sky. Earth blocks cosmic rays from the Northern Hemisphere, so IceCube sees only muons made by those mysterious, high-energy neutrinos from the north.

Discussion Questions

1. Why does the Ice Cube observatory look down rather than up, unlike all other telescopes?
2. The project cost an estimated $271 million. What were the assurances that this money would not be wasted?
3. The neutrino originated as a hypothesis in a theorist’s head. How has it come to be accepted by physicists? What other types of matter and energy (Higgs bosons, dark matter, dark energy) have physicists thought up, and how certain are we that they exist?
4. If neutrinos cannot be seen and can hardly be detected, why spend money trying to detect them?
5. Why does Ice Cube’s “detector” need to weigh 1 billion tons?

Lesson Plans/Activities

1. Polar TREC has professional development programs for teachers, focused on science at both poles.
2. A broad range of activities and programs related to ice and the poles.
3. The popcorn neutrino experiment shows how Wolfgang Pauli first “invented” a particle that “nobody could detect.”
4. Home-made cloud chamber shows how technology can make the invisible (cosmic rays) visible.