The Thin Blue Line

S1, E3: Discover how something as flimsy as an envelope of gas - an atmosphere - can create some of the most wondrous sights in the solar system. Professor Brian Cox takes a flight to the top of earth's atmosphere, where he sees the darkness of space above and the thin blue line of our atmosphere below. Against the stunning backdrop of the glaciers of Alaska, Brian reveals his fourth wonder: Saturn's moon Titan, shrouded by a murky, thick atmosphere.