Light and Dark

Light and Dark is a two-part BBC documentary hosted by Jim Al-Khalili, looking at light and darkness in terms of their astronomic importance, and their role in our understanding of the Universe. In the series, Professor Jim Al-Khalili shows how, by uncovering its secrets, scientists have used light to reveal almost everything we know about the universe. But in the last 30 years we have discovered that far from seeing everything, we have seen virtually nothing. Our best estimate is that more than 99 percent of the universe is actually hidden in the dark.

Episode 1 - Light

Episode 1 - Light
Professor Jim Al-Khalili shows how scientists have used light to reveal almost everything we know about the universe. In the 3rd century BC, the Greek mathematician Euclid discovered that light travels in straight lines. In Renaissance Italy, Galileo Galilei did just that by using the lenses of his simple telescope to reveal our true place in the cosmos. With each new insight into the nature of light came a fresh understanding of the cosmos. It has allowed us to peer deep into space and even revealed the composition and life cycles of the stars.

Episode 2 - Dark
Professor Jim Al-Khalili tells the story of how we went from thinking we were close to a complete understanding of the universe to realising we had seen almost none of it. Today, our best estimate is that more than 99 percent of the cosmos is hidden in the dark, invisible to our telescopes and beyond our comprehension.

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