Curtmudgeon, if you dismiss stellar evolution you must dismiss pretty much all of physics because the foundation of stellar physics is basically F=ma.

Stars do not change fast as you point out, therefore forces in stars balance. The forces are (mostly) gravity and internal pressure. The energy for the internal pressure comes from thermonuclear reactions (this is the fundamental step. And the evidence for nucleosynthesis in the Sun is now overwhelming). Thermonuclear reactions change the chemical composition. The change of chemical composition in the core makes the star evolve.

Sure this model is not directly testable in a lab. Sure different type of stars may be completly unrelated. But the evidence is not just the different stars you see with some arbitrary link invented to make it look good. Stellar models explain and reproduce well stellar pulsations, the abundance correlations, stellar winds, explosive events, cooling curves of white dwarfs, for example, across many varieties of stars without fudging the physics. This theory does surprisingly well given its simplicity.

Stellar evolution can be discounted like everything else in the world but it is firmly established in very basic science.

<font size=-1>[ This Message was edited by: frenchy on 2002-06-27 16:30 ]</font>