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: