I seem to recall from school days in the sixties and seventies that some astronomers believed that there was a progression from spiral to elliptical over time. I remember seeing illustrations of galaxy types that may have had arrows depicting an assumed evolution over time.Chris Peterson wrote:The classifications of spiral, lenticular, and elliptical are morphological, and may not be clearly related to galaxy evolution.
Of course, back in those days, there were no large adaptive optics or orbiting telescopes, nor were there super computers doing massive galactic merger simulations. The view has greatly improved.
As far as the coming merger between our galaxy and Andromeda is concerned, is it certain that "Milkdromeda" must ultimately wind up as an elliptical? Is there a chance that it could become a super large spiral?
Bruce