YouTube! Edgar here, and welcome to Artifexian!
Here you will learn everything you ever wanted to know about worldbuilding, and then some!
So, last time, we talked about spiral galaxies. But, are other types of galaxy habitable?
Well, let's start with my old nemesis, the elliptical galaxy.
Remember how the bulge region of spiral galaxies wasn't a great location for a fictional world?
Well, ellipticals are essentially all bulge!
The lack of interstellar gas and dust, no star formation, stellar density, and the radial orbits of stars
All make housing a habitable world within an elliptical galaxy very challenging indeed.
And, from a worldbuilding point of view, mapping an elliptical galaxy isn't all that interesting,
given that they don't contain a wide variety of stellar types, and they're almost totally featureless!
But say you reeeeally do want to house a world within an elliptical galaxy.
What effect would the galaxy have on your world?
How might the night sky look?
How would it differ for different locations within the galaxy?
I feel it would definitely be a lot more uniform in appearance.
But would it be brighter, or darker?
Would we see any of the numerous globular clusters?
What if your world was a way out from the core?
Could the sky on the non-coreward side of your planet look more like our sky?
Would there be constellations?
And if not, how would the heavens inform your world's culture?
Okay, so maybe ellipticals aren't your bag.
What of irregular galaxies?
Irregular galaxies are understood to be the result of galactic collisions, making them at best chaotic systems.
Note: chaos and habitability do not readily mix.
Rampant star formation, stellar jets, and radioactivity would make habitability within irregular galaxies a real challenge!
However, their shape would be fascinating to map.
In fact, I would say much more so than spiral galaxies.
They contain a vast array of different star types, which would add variety to a setting.
And their shape can be utterly determined by the worldbuilder!
I. E., Total creative freedom.
So let's muse on irregular galaxies for a second.
What would the night sky look like?
Well, given the chaotic nature of irregular galaxies,
some areas of the sky could feature a great density of stars,
while some areas might have no visible stars at all.
There could be dust and gas lanes distributed at random throughout the night sky.
Again, total creative freedom, which could produce a very unlikely, but very colorful setting.
Invisible, or ultra-faint galaxies, galaxies much less luminous than our own,
that contain as little as 1,000 stars and are dominated by dark matter,
would be TERRIBLE candidates, as there simply isn't enough stuff around to create a viable planetary system.
However let's get a little Star Wars here and use a dab of Handwavium.
Let's say your planet does exist within an ultra-faint galaxy.
Again, ask yourself, "What would the local setting look like?"
Well, the few stars contained within these galaxies would almost definitely be too dim to see with the naked eye.
Thus, the sky would be utterly black.
Only the planets could be seen dimly trekking across the night sky.
Okay, now these are only my opinions and musings, and shouldn't be taken as fact.
And as far as galactic habitability goes, there is no fact.
Just speculation, and heavily criticized scientific theories.
So I'd love it if you guys would go ahead and speculate in the comments.
Is habitability likely within different galactic types?
What galaxy would you house your world in?
How would you justify it?
And how would the galaxy affect life on your planet on a cosmic and cultural level?
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