From Ken Lignar, Westbrook, Connecticut, US
I enjoyed reading Jacklin Kwan’s piece about John Pendry and his invisibility cloak. As the discussion talked about the way that the structure of metamaterials can interact with electromagnetic radiation (light), some questions entered my mind. Does empty space, with all of the virtual particles within it, have a structure? Is empty space a temporal metamaterial? The questions may never be answered, but it is good to ponder all the aspects they bring about (11 April, p 40).
