Evidence of alien life, a clue about the rise of bowel cancer, and a new colour?

Madeleine Finlay and Ian Sample discuss three intriguing science stories from the week. From a hint at alien life on a distant planet, to a clue in the search for answers over why colon cancer rates are rising in the under 50’s, and news from a group of scientists who claim to have experienced a colour no one has ever seen before.. Help support our independent journalism at theguardian.com/sciencepod