Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
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In 1999, Harvard physicist Lene Hau was able to slow down light to 17 meters per second and in 2001, was able to stop light completely.
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Electric lights for trees were first used in 1895.
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The light hitting the earth right now is 30 thousand years old.
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An international team of astronomers has spotted the farthest known gravitational lens and, as Albert Einstein predicted, it is a galaxy that deflects and intensifies the light of a much further object.
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It takes a photon 170,000 years to travel from the core of the Sun to the surface, but only 8 minutes to travel the rest of the way to Earth.
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MIT has developed a camera that captures the speed of light at a trillion frames per second.
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During photosynthesis, plants emit light humans can’t see, but NASA can see that light from space - and they've even made maps of it!
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