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Mystery Behind Galileo’s Visual Illusion Discovered

Why was it that when Galileo viewed Venus and Jupiter with the naked eye, Venus, the brighter planet, appeared larger, but when viewed through a telescope, Jupiter appeared larger?
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Happy birthday, Galileo!

Why was it that when the Italian astronomer viewed Venus and Jupiter with the naked eye, Venus, the brighter planet, appeared larger, but when viewed through a telescope, Jupiter appeared larger?

This stumped Galileo, who thought the “irradiation illusion” might be caused by the human eye. According to a recent study by SUNY’s Dr. Jose-Manuel Alonso, published in the journal Proceedings of the National Academy of Sciences, the illusion is caused by the distortion of light-sensitive neurons.

Find out more in the video here:

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