Prof. Colin Rourke’s presentation on De Sitter Space. Willem de Sitter found his eponymous space in 1917 at approximately the same time that Einstein completed his general relativity theory. Regarded as a curiosity it was emasculated by Hermann Weyl’s widely accepted “coherency postulate”. But, properly understood, the space fits recent observations (WMAP and Supernovae) perfectly and provides a fully Copernican model for the universe with no Big Bang, dark matter or inflation. As a bonus it also gives a non-cataclysmic explanation for Gamma Ray Bursts.