The Milky Galaxy

The Milky (nurturing) Galaxy is a combination of two related novellas set in the same small, unregarded corner of the multiverse.
In the first novella, in the 24th century, the Earth is ruined. Bio-diversity is gone. What is left is foul air, poisoned soil, filthy water, and a greatly reduced population of Humans struggling to survive in the dystopian environment. The wondrous beauty of a living globe more than four billion years old perfectly suited to support millions of diverse species is no more.
Only the Rich live comfortably in geodesic domes five miles high which selfishly preserve some of the former glorious wonder, the clean air, water, and healthy food of the now collapsing Earthly biosphere.
In the fragmented slums between the Domes, descendents of the former Working Class - whose livelihoods were usurped by robots mid-21st century - cling to a precarious secret existence in old buildings sealed against the raw, polluted, unfiltered air and water of ruined Earth. Living in peace with the ultra-privileged Dome dwellers, except as slaves whose lives would be worth nothing, is clearly impossible.
Large, green, ameboid Aliens come to Earth and take away members of the former Working Class to settle them on healthy planets elsewhere in the Galaxy. The Aliens accidently leave an Alien child behind. Zee (the ameboid Aliens have only one gender) struggles to survive outside the Domes and find a way to Reproduce, to save hir memories for the future of hir species.
In the second novella, a wastrel young man belonging to a Rich Dome family is sent against his will by his authoritarian father out into space to find a suitable, un-ruined planet where the Rich Families of Earth can transfer their "civilization:" their food animals, their enslaved women, and their capitalist economy. Past the worm-hole in the alpha Centauri star-system, the young man finds a thriving Anarkhist society of Human beings - living with green, ameboid aliens and others - inhabiting a star system with three suns. To his surprise, he falls in love with a free-Human female; and yet he still intends to conquer the planet and bring to it the "blessings" of Capitalism, because it will make him a Rich Earthman. Disaster ensues.