He made headlines in 2005 when he criticised the Katie Melua song "Nine Million Bicycles" for inaccurate lyrics referring to the size of the observable universe. Singh proposed corrected lyrics, though he used the value of 13.7 billion light years; accounting for expansion of the universe, the comoving distance to the edge of the observable universe is 46.5 billion light years. BBC Radio 4's "Today" programme brought Melua and Singh together in a radio studio where Melua recorded a tongue-in-cheek version of the song that had been written by Singh.