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Evolution of Galaxies - Evolution of Galaxies There are...

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Evolution of Galaxies There are several senses in which galaxies evolve with time, not all necessarily running at the same rates for various kinds of galaxy. We may distinguish for convenience evolution of stellar populations, chemical abundances, and dynamics of a galaxy, remembering that in real galaxies these are all tied together at some level. I will cover the basic principles needed to understand modelling these processes, and observational approaches to each one. The likelihood of observing galaxy evolution can be seen from comparing several relevant timescales. The Hubble time is in the range 1-2 × 10 10 years. This matches the main-sequence lifetime of solar-mass stars, making it many generations of more luminous massive stars. And dynamically, the rotation period on our part of the Milky Way is 0.25 Gyr, so the relaxation time for a massive galaxy to form structure should be several Gyr. Population evolution combines the history of star formation in a galaxy and stellar evolution of
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