Kids and curious adults alike have long asked the question of why the sky is blue. While science has come a long way in explaining the sky’s appearance, people didn’t always know the answer. But as early as 1509, Leonardo Da Vinci offered the first recorded explanation as to why the sky is blue.
Da Vinci wrote that the sky looked this way because of the way air scatters light—and he was pretty close to being correct. While Da Vinci believed the scattering was caused by light reflecting off of water vapor, it is actually caused by all of the particles and gases in the air. Air particles scatter blue light from the sun more than red, leaving us with the blue skies we all know. (And what about sunsets? Those blue particles of light scatter and move away from the sun, which is why looking at a sunset yields red and yellow shades.)
The reasoning behind the sky’s coloring was only one of Da Vinci’s important discoveries during his lifetime. He also figured out why the moon is dimly visible during its crescent phase, designed dozens of inventions and painted the Mona Lisa, one of the most famous paintings in the world.