The story of galaxy evolution in full colour

A Holy Grail of modern astronomy is understanding the origin of Edwin Hubbl e's morphological sequence of galaxy types. What made some collapsing gas c louds turn into elegant spiral systems like our own Milky Way, whereas othe rs became smooth, featureless ellipticals? More fundamentally, does the tax onomic scheme introduced by Hubble in the 1920s have any physical relevance ? The Space Telescope that bears Hubble's name is providing answers to thes e and other questions in the context of modern theories of structure format ion.