Reddit reviews Diaspora

You want "Diaspora" by Greg Egan., which can be had on Kindle for 3 bucks. Don't be fooled by the garbage cover, he is a published author.

Greg Egan is about hard as you can get. Considering that all of his books are backed by science and mathematics, he makes other hard SF authors come across as wieners. When he writes a book, he creates a page on his website that has all of the math and physics he used in writing the book. I love his books.

The last one I read by him was written because he wanted to explore the idea of aliens discovering the theory of relativity without being able to see space and how they would do it.

Some optimistic scifi I love is Greg Egan's books Diaspora, Schild's Ladder and Incandescence. Each book take place in a separate world but each share a similar trans-humanist utopia as their setting. Everyone is immortal, can transfer between bodies, and war (and in most cases, death) is completely unheard of.

[Diaspora]

https://smile.amazon.com/Diaspora-Greg-Egan-ebook/dp/B00E83YOEI?sa-no-redirect=1

Diaspora by Greg Egan

>In 2975, the orphan Yatima is grown from a randomly mutated digital mind seed in the conceptory of Konishi polis. Yatima explores the Coalition of Polises, the network of computers where most life in the solar system now resides, and joins a friend, Inoshiro, to borrow an abandoned robot body and meet a thriving community of “fleshers” in the enclave of Atlanta.

>Twenty-one years later, news arrives from a lunar observatory: gravitational waves from Lac G-1, a nearby pair of neutron stars, show that the Earth is about to be bathed in a gamma-ray flash created by the stars’ collision — an event that was not expected to take place for seven million years. Yatima and Inoshiro return to Atlanta to try to warn the fleshers, but meet suspicion and disbelief. Some lives are saved, but the Earth is ravaged.

>In the aftermath of the disaster, the survivors resolve to discover the cause of the neutron stars’ premature collision, and they launch a thousand polises into interstellar space in search of answers. This diaspora eventually reaches a planet subtly transformed to encode a message from an older group of travellers: a greater danger than Lac G-1 is imminent, and the only escape route leads beyond the visible universe.