How can Santa Claus visit all children within one day? And why can nobody see him? In collaboration with the two regional Danish television channels TV2 Fyn and TV2 Syd , scientists from the University of Southern Denmark have made a daily Christmas Advent with short talks combining Science and Christmas. Thomas Aa. Ryttov explains how Santa Claus might get around to all the kids in the world on Christmas eve using wormholes:And Francesco Sannino explains why Santa Claus cannot be seen:A list of all the talks can be seen on SDU's home page .