Edwin Hubble escaped the glare of ‘Orange county’ by retreating to a mountaintop observatory north of Pasadena, where he recorded the motions of the galaxies that led to his discovery of the expanding universe. But it wasn’t sodium that caused him difficulties. Potassium burns with a mauve flame which can sometimes be seen in a gunpowder explosion or when lighting a match. One night Hubble was excited to detect a potassium spectrum while he examined the galaxies through the world’s most powerful telescope. But it soon became apparent that the reading must be false. Eventually Hubble realized that the equipment had picked up the light from the potassium in the match that he had used to light his pipe.