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In 1818, Siméon Denis Poisson argued that if light were a... | funfact.wiki | funfact.wiki
In 1818, Siméon Denis Poisson argued that if light were a wave, a bright spot should appear at the center of a circular object's shadow — which he thought was absurd. But when Arago actually ran the experiment, the bright spot appeared, proving light's wave nature.
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