What is Light?

In 1676, Danish astronomer Ole Rømer discovered that light "delayed" - as he himself put it. Light has a velocity, and the discovery excited figures like Isaac Newton.

Astroophysicist Lars Occhionero from Kroppedal Museum tells this evening about the Renaissance man Rømer and about light as a phenomenon: what is light really, and who was the man behind the discovery that later became one of the country's most powerful?