What is the Zwicky Constant?
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Q. What is the Zwicky Constant?
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A. As light travels through the Universe's gravitational field, it slowly loses energy. The Zwicky Constant defines this loss.
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Q. How is it defined?
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A. The Zwicky Constant is the distance light travels to lose half its energy.
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Q. How is it measured?
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A. Spectral lines in the light from distant objects are shifted towards redder (lower-energy) wavelengths (red-shifts), and these red-shifts are greater, the greater the distance the light has travelled.
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Q. What's the value of the Zwicky Constant?
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A. About 7.7 billion light-years.
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