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African Astronomy III
A worldwide consortium will soon decide where to build a globe-spanning telescope array that could study some of the most energetic objects and events in the universe. If everything goes as planned, it’ll consist of a network of more than a hundred telescopes. About 20 of them will be in the northern hemisphere — in Arizona, Mexico, or the Canary Islands. But most will be in the southern hemisphere — in either Chile or Namibia.
CTA — the Cherenkov Telescope Array — is designed to study gamma rays. They’re produced by exploding stars, hot gas around black holes, and other powerful events. They may even be created by collisions between particles of dark matter.
Gamma rays produce flashes of blue light when they enter Earth’s atmosphere, and that’s what CTA will see. Scientists will study those flashes to learn more about the origin of the gamma rays.
Under the current plan, the telescopes in the southern hemisphere will come in three sizes — from about 15 feet in diameter to as much as a hundred feet. Each size will be sensitive to different wavelengths, allowing scientists to study many different types of gamma-ray objects.
Several Cherenkov telescopes are already in operation. The largest, known as HESS, is in the desert of Namibia, which has especially clear, dark skies. If Namibia gets the nod for CTA, then it would be built not far from HESS — giving that African nation the best view of the gamma-ray universe.
Script by Damond Benningfield, Copyright 2015