Stargazers in parts of Europe were stunned by an unusual sight on Monday evening: a large, glowing blue spiral in the sky.

You might think that explaining why the sky is blue would be kind of simple. But even a brief explanation of it requires a lot of science. The colors of everything you see are produced in ...

It was around 1870 when the British physicist John William Strutt, better known as Lord Rayleigh, first found an explanation for why the sky is blue: blue light from the sun is scattered the most ...