Why is the sky blue?

“Why is the sky blue?” is a natural question, asked by many people, children and adults alike. In this video, Don Lincoln answers the question and even reveals the surprising fact that it should really be purple.

A man with gray hair, glasses and a black blazer smiles. To the right of him, the question "Is light a wave or a particle?"

Quantum mechanics is one of the most confusing fields of contemporary physics. Fermilab’s Don Lincoln introduces the big ideas and prepares the viewer for a follow-on video that is even more mind-blowing.

From Super Interessante, Jan. 31, 2021: A team of researchers from Fermilab and the National Observatory in Brazil used the light of solitary stars to calculate the mass of some of the largest structures in the cosmos — galaxy clusters. In addition to taking the most detailed measurement ever published of intracluster light, the team’s new method of measurement can help further investigate dark matter.

From Mission Unstoppable, Jan. 26, 2021: Fermilab scientist Jessica Esquivel explains how light particles work with makeup to create a look.

The motion of light depends crucially on the material in which it is traveling. When light passes from one medium to another, an unexpected thing happens: The direction of travel changes. There are many explanations out there for why this happens, and many of those explanations are wrong. In this 14-minute video, Fermilab scientist Don Lincoln explains the reason.

Misty night

At Wilson Hall late one night, the fog creates an interesting glow around the lights on the front steps.

At Wilson Hall late one night, the fog creates an interesting glow around the lights on the front steps.