Cosmology: milky way size is enormous (Introduction)

by David Turell , Saturday, June 01, 2019, 14:43 (2003 days ago) @ dhw

QUOTE: "So the next time you’re speeding through intergalactic space in your brand new galaxyship—mere starships are so twenty-third century—you can brag to any aliens you meet beyond the Milky Way that you hail from a gargantuan galaxy. But chances are, so can they."

DAVID: our massiveness is attested to by the number of satellite galaxies. But our uniqueness is in our rarity in the universe. We are a privileged planet in a special galaxy. God at work? The article suggests life will only be in our kind of galaxy.

dhw: Rareness is not the same as uniqueness, and even if it is true that life can only occur in big galaxies, we do not have a clue how many big galaxies there are in the universe. In all honesty, I don’t see the point of this article. And one can’t help wondering why your God bothered with all the small galaxies if his only purpose was to produce H. sapiens.

You may have forgotten, but one of the requirements of life is a planet which is far from the dangerous activity in the center of a galaxy. The Milky Way grew/grows by swallowing smaller galaxies, and we sit out at the two-thirds point on the second spiral arm in a quiet neighborhood. Same evolutionary story you try to deny as God's method: start a universe, evolve it, grow/evolve the right-sized galaxy, create a perfect Earth planet and evolve it for life to start, evolve life to create humans. All in the history presented.