Two scenarios for the next 500 million and 5 billion or more years in the future: Posthuman diversity and Grabby Aliens. Although these could also be two stages in or aspects of a single speculative scenario
Assuming beings from Earth one day become an interplanetary, interstellar, galactic or intergalactic civilisation, the chances are they will look nothing like humans of today. They will however be descended from modern humans, or from human-made AI perhaps, in the same way that all higher animal life on Earth goes back to the Cambrian explosion. The term “Posthuman” is used here to refer to beings that come after humanity (more).
This theme actually goes back to the earlier 20th century, even predating Space Opera. Last and First Men is a "future history" science fiction novel written in 1930 by the British author Olaf Stapledon. It follows future races or species of humanity on various planets of the solar system, with civilisations rising from and falling back into savagery over millions of years. The book anticipates later themes such as genetic engineering, as well as the idea of the supermind; a consciousness composed of many telepathically linked individuals.
Writing in the 1930s, science fiction was for the most part limited to our own solar system, sometimes taking the form of “planetary romances”, such as the primordial swamps of Venus and the dessicated deserts of Mars, home to an ancient and dying civilisation. The idea of an Interstellar, galactic stage rather than a merely solar system one only really took off with Asimob’s Foundation series, which began in the following decade.
C.M. Kösemen’s All Tomorrows, written in 2006, presents an updated version of Last and First Men, being upgraded to Interstellar in scope. follows the history of humanity across space and deep time. This includes genetically-engineered humans called Star People, a malevolent and superior alien species called the Qu, who bioengineer humans into a range of forms, similar to but more extreme than those in Dougal Dixon’s Man After Man, the Gravital, who replace their human bodies with machine forms, and proceed to annihilating other life in the galaxy, before themselves being destroyed by another posthuman clade, the Asteromorphs, and so on.
Grabby Aliens offers the possibility that humanity, or rather, our distant post-human and not even recognisable descendents, will be among the civilisations that, in the long-term (of billions or trillions of years) expand to fill the universe.
The Grabby Alien theory offers an interesting interpretation of the Fermi paradox (where are the aliens?). The answer is that we wouldn’t see evidence of any alien super civilisation until it s nearly upon us.
Richard Baker’s as yet unpublished and unfinished “Episteme Universe”, presents a different version of the same basic scenario. It is based on the premise that total human power generation continues to double every fifty years. By sixty million years from now, the Episteme has expanded to permeated the entire Virgo Supercluster, controlling around 47,000 galaxies [pers comm 14 Feb 2023].
But there’s no reason that progress or evolution should follow a strictly linear route. In fact it is unlikely t would do so. It’s more likely that terragens (beings descended from beings from Earth) would arrive at a Grabby Aliens outcome via a more round-about path, for example an “All Tomorrows” route. Indeed, that book has humanity expanding beyond the galaxy and encountering another species (but more friendly than the Qu).
This timeline continues Deep Time into the future, being the counterpart of the Phanerozoic (next 500 My) and the history of the Earth (next 5 Gy), respectively. However, posthuman and techno-utopian (or just generic ultratech, e.g. grabby aliens) scenarios would radically alter some of these predictions. For example, megascale and geoscale engineering could maintain optimal environments on Earth, avoiding the extinction of life caused by increasing luminosity of the aging sun. Sun lifting (removing excess solar mass) could also reduce the output and restore the sun’s output to earlier conditions
Page by M Alan Kazlev, 2023