Colour: The Spectrum of Science Episode Rating Graph

In the first episode, Helen seeks out the colours that turned planet Earth multicoloured. To investigate the essence of sunlight Helen travels to California to visit the largest solar telescope in the world. She discovers how the most vivid blue is formed from sulphur atoms deep within the Earth's crust and why the presence of red ochre is a key sign of life. In gold, she discovers why this most precious of metals shouldn't even exist on the surface of the planet and in white, Helen travels to one of the hottest places on Earth to explore the role salt and water played in shaping planet Earth.

The raw, early Earth had plenty of colour, but that was nothing compared with what was going to come next. That canvas was about to be painted with a vast new palette - and the source of those colours was life. Green is the colour of the natural world and yet it's the one colour that plants have evolved not to use.

The colours that we see are only a fraction of what's out there. Beyond the rainbow there are colours invisible to our eyes. In this episode, Dr Helen Czerski tells the story of scientific discovery. To see the universe in a whole new light, Helen takes to the skies in a NASA jumbo jet equipped with a 17-tonne infrared telescope.