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The Xeelee Sequence
The Xeelee Sequence is a collection of interconnected science fiction stories and novels that explore a future universe encompassing millions of years and featuring advanced civilizations, space travel, and encounters with the enigmatic Xeelee, a highly advanced alien species.
The series follows an intergalactic war between humanity and the Xeelee, and the Xeelee’s own cosmos-spanning war with dark matter entities called Photino Birds. Humanities expansion into the stars after overcoming several earlier extraterrestrial occupations also plays a prominent role.
The Xeelee Sequence deals with many concepts found in traditional science fiction stories such as time travel, wormholes, artificial intelligence, exotic materials and multi-universal themes. It also imaginatively explores topics of cosmic ambition, human frailty and the ultimate nature of existence.
Many other species and civilizations are also prominently featured, including the Squeem (a species of group-mind aquatics), the Qax (beings whose biology is based on the complex interactions of convection cells), and the Silver Ghosts (colonies of symbiotic organisms encased in reflective skins).
Raft (1991)
Stephen Baxter’s highly acclaimed first novel and the beginning of his stunning Xeelee Sequence. A spaceship from Earth accidentally crossed through a hole in space-time to a universe where the force of gravity is one billion times as strong as the gravity we know. Somehow the crew survived, aided by the fact that they emerged into a cloud of gas surrounding a black hole, which provided a breathable atmosphere. Five hundred years later, their descendants still struggle for existence, divided into two main groups. The Miners live on the Belt, a ramshackle ring of dwellings orbiting the core of a dead star, which they excavate for raw materials. These can be traded for food from the Raft, a structure built from the wreckage of the ship, on which a small group of scientists preserve the ancient knowledge which makes survival possible. Rees is a Miner whose curiosity about his world makes him stow away on a flying tree—just one of the many strange local lifeforms—carrying trade between the Belt and the Raft.
Raft is the first book in the Xeelee Sequence series and sets the table for the strange and wonderful universe in which this epic is placed. The novel takes place in a universe where gravity is much stronger than in our own, 1 billion times stronger in fact and it follows the journey of a group of humans who find themselves stranded on a “raft” in this unusual universe.
The story begins on a planet called Earth, which exists in a universe with a much higher gravitational constant. Humans on this planet have adapted to survive under extreme gravity. The protagonist, Rees, is a young man who dreams of becoming a spaceman and exploring the universe. However, due to the strict social structure of his society, his dreams seem out of reach.
One day, a catastrophic event occurs on Earth. Rees and a few others are propelled into space and find themselves on a “raft” – a flat, disc-like structure floating in the higher-gravity universe. The raft is composed of debris from their destroyed planet and serves as their only means of survival. They must learn to adapt to the harsh conditions and find a way to navigate the raft, which is constantly shifting and changing.
As Rees and his companions explore the raft, they encounter various dangers, including deadly creatures and other stranded survivors. They also discover remnants of advanced alien civilizations that existed in this universe long before humans arrived. These remnants offer clues about the enigmatic Xeelee, a powerful alien race that controls vast resources and wields tremendous technological prowess.
Driven by their desire to survive and understand their predicament, Rees and his companions embark on a perilous journey across the raft. Along the way, they encounter numerous challenges and witness the vastness and strangeness of the higher-gravity universe. They come to realize that their survival is not only dependent on their resourcefulness but also on uncovering the secrets of the Xeelee and their connection to the raft.
Raft sets the stage for the larger Xeelee Sequence series, introducing readers to the unique universe and the challenges humanity faces in its struggle against the Xeelee. The novel combines hard science fiction elements with grand cosmic concepts, exploring themes of survival, evolution, and the search for meaning in a vast and mysterious universe.
Timelike Infinity (1992)
2000 years in the future, the solar system has fallen under the domination of an alien species, the Qax. But into this world appears a spaceship launched over 1500 years ago, intended to establish a link through which time travel is possible. To humans this is a chance to reverse time.
Timelike Infinity is the second book in the Xeelee Sequence series and while the Xeelee take no active role in this story they are finally introduced to the reader and are shown to be enigmatic, godlike, and far removed from any other sentient life in terms of evolution. Spacefaring races all across the universe vie for leftover Xeelee tech, since it is the only way to make any sort of progress among the stars, even though none of these races really seems to understand it.
The novel starts off around 5200 AD with the Earth and humanity suffering under the Qax, the second alien species to conquer humanity. The Qax, though few in number, control space in their massive, organic spaceships and have largely shut down humanities space travel. Earth is now a giant farm producing food for export to other alien species while humans live only on processed kelp. Besides shutting down humanities space programs and other technological developments that improved human’s quality of life, the Qax also ended the treatments for human longevity, condemning humans to their natural lifespan once again. Humanity searches for a way to foment a revolution and break the chains of alien occupation.
However, 1500 years ago, Michael Poole, along with a team of engineers and scientists, created a ‘wormhole’ in Jupiter’s orbit, with one end left there and its ‘pair’ dragged out toward the center of the universe by a sub light spacecraft. When the Qax conquered humanity, they destroyed the wormhole around Jupiter, and have waited for the day when its former pair partner would return to the Solar system. That day finally came, and the wormhole pair returned to its orbit around Jupiter and the Qax were alerted to its presence.
Despite the tyranny of the Qax and their efforts to prevent humans from using it, a ship left Earth and using an alien hyperdrive, shot through the wormhole gate. This allowed them to, in effect, travel 1500 years back in time prior to the Qax invasion.
From there the Qax, nervous about the implications of time-traveling humans, forced humanity to build a second set of wormholes that they used to visit the future. With the idea that seeing their future could help provide information on how best to remain in control of humans in the present. This creates 3 timelines, for the past, present and future with humans attempting to break away from Qax control and the Qax attempting to keep humans under their control.
The novel continues to follow the three timelines as each party attempts to gain the upper hand on the other, with the Qax eventually deciding to attempt to wipe out humanity completely. In the end the humans defeat the Qax and break free of their occupation.
During the course of the novel, insights into the Xeelee are occasionally hinted, and an important revelation pertaining to a very large universal project they are helming is dropped in the quote below. It is referred to only as the “Ring”.
”A Ring. A torus. Composed of some unknown, crystalline substance. A thousand light-years across. Rotating at a respectable fraction of the speed of light. It was massive. It had caused a well in spacetime so deep that it was drawing in galaxies, including Earth’s Milky Way, from across hundreds of millions of light-years. It is an artifact. A Xeelee construct. [He] watched the Xeelee build it.”
Timelike Infinity combines elements of hard science fiction, time travel, and cosmic warfare to create a sprawling and epic narrative. It explores complex themes such as the nature of time, the limits of human understanding, and the profound impact of extraterrestrial civilizations on our existence. The novel provides a rich and imaginative exploration of the Xeelee Sequence universe, setting the stage for further books in the series.
Flux (1993)
Imagine a race of submicroscopic humans, genetically engineered to live in the universe’s most hostile environment, the turbulent superfluid mantle of a neutron star. Imagine that the memory of the superbeings who created them has been kept alive from generation to generation. Now imagine the most incredible family reunion in history–and you’re ready for the latest mind-expanding adventure.
Star humans were engineered to exist within the mantle of a star, mere tools of their Earth-evolved makers in a war against the Xeelee, owners of the universe. Stephen Baxter’s third novel in his magnificent Xeelee Sequence is an exotic and endearing story of an abandoned people.
Flux is the third book in the Xeelee Sequence series and much like the first book of the series depicts humans living in a strange, extreme and hostile world outside the confines of our own Earth.
The book begins with an extreme “glitch” within the neutron star which is described as an event (much like an earthquake) that is caused by instabilities of its magnetic field and is caused by changes in the star’s rotation. This extreme glitch threatens to destroy their home.
Due to damage caused by the glitch, the main character’s group is forced to leave their settlement in search of new food sources. During their journey they come upon a massive city named Parz, that also contains star-human residents, and it has a well-functioning economy and society.
After some time in the city, it becomes apparent that the main character’s ancestors originally lived in Parz, but left due to subscribing to a non-popular belief. Their belief was that the Xeelee should ultimately be accepted as being for the good of humanity, which was not accepted by the city’s leaders. The common sentiment was and still remains to be that the Xeelee were humanities enemy and must be defeated at all costs.
Over the course of the novel, which remained centered in Parz, the characters realize the instabilities are actually being caused by the attack of the Xeelee, and the next instability could destroy both the city and possibly the star itself.
An effort is made to reach the center of the neutron star where it is believed a special spacecraft and a cache of ancient weapons exists. Supposedly left by the humans who created the star-humans.
Once arriving at the star’s center, they discover that the neutron star has been turned into a missile and has been aimed directly at the Xeelee’s “Ring” project and is the reason for their attacks.
After further discovery they learn that their entire existence was created by regular humans only to ensure the neutron star remained on its target. Once the neutron star hit its target, both it and its inhabitants would cease to exist. With this in mind, they decide to alter the course of the neutron star and moved it out of the path of the Xeelee Ring.
Once the neutron star’s path was altered enough to miss its target, the Xeelee stopped their attacks.
Ring (1994)
Michael Poole’s wormholes constructed in the orbit of Jupiter had opened the galaxy to humankind. Then Poole tried looping a wormhole back on itself, tying a knot in space and ripping a hole in time. It worked. Too well.
Poole was never seen again. Then from far in the future, from a time so distant that the stars themselves were dying embers, came an urgent SOS–and a promise. The universe was doomed, but humankind was not. Poole had stumbled upon an immense artifact, light-years across, fabricated from the very string of the cosmos.
The universe had a door. And it was open…
Ring is the fourth book within the Xeelee Sequence series and follows two parallel plots, one involving the exploration of the interior of the Sun and the other involving a generation spaceship on a 5-million-year journey.
An AI is abandoned for 5 million years in the interior of our Sun and is left with nothing to do but observe. The AI discovers a new dark-matter based life form, dubbed the “Photino Birds”, that gradually drains the energy of the star’s core which ends fusion and prematurely ages it into a white dwarf. This bypasses any risk of the star exploding or going supernova and allows these life forms the ability to remain in the preferred habitat (star cores).
The generation ship is headed for a wormhole from our Solar system in which to jump 5 million years into the future. And due to the effects of relativistic time dilation a round-trip journey is planned, with the ship returning to Earth with only 1000 years having passed for those onboard. But upon their arrival in the future, their end of the wormhole has been destroyed leaving them trapped.
Once in the future the generation ship notices that the sky is filled with red stars indicating that they have aged much faster than expected. The ship makes contact with the AI still lingering in the Sun, who then explains their observations of the Photino Birds life forms. They arrive at the conclusion that these dark-matter life forms do not exist in only our Sun, but in every star and are rapidly aging them to keep their home environments stable (i.e., no supernovas).
The Xeelee, masters of the baryonic universe, have known about the photino birds and their actions affecting all stars and have been aiming to thwart them. A cosmic war has been raging between the Xeelee and the Photino Birds for eons. However, the baryonic universe is doomed and even the mighty Xeelee cannot prevent its eventual downfall (with baryonic matter comprising of only 4-5% of the total matter in the universe, the Xeelee are massively overwhelmed by the dark-matter Photino Birds as dark-matter comprises 3-4 times more).
The Xeelee “Ring” has been their answer to losing the cosmic war. It is an immense megastructure over 10 million light years in diameter that spins at nearly the speed of light, with its intended function of opening a portal to a new universe to allow baryonic-matter species to escape this one.
The following quote from the novel provides an interesting in-universe description of the Xeelee Ring for a real-world phenomenon. In the series, it is being labeled as the object known as the “Great Attractor” which is a point in space where all of the galaxies of our local group are moving toward in our galactic cluster.
“The cosmology here is… spectacular. We have, essentially, an extremely massive torus, rotating very rapidly. And it’s devastating the structure of spacetime. The sheer mass of the Ring has generated a gravity well so deep that matter—galaxies—is being drawn in, toward this point, across hundreds of millions of light years. Even our original Galaxy, the Galaxy of mankind, was drawn by the Ring’s mass. So we know that the Ring was indeed the ‘Great Attractor’ identified by human astronomers.”
The Xeelee end up allowing the last of the humans that make it to the Ring to pass through it and find sanctuary and a new home world in another younger universe. The novel concludes with the end of the universe where the decay of the last protons takes place and dark-matter life forms declare victory with the dispersion of any remaining baryonic matter.
Vacuum Diagrams (1997)
Includes 23 short stories and novellas that tells the story of Humankind – from there beginning, all the way to the end of the Universe itself.
“And everywhere the Humans went, they found life…”
The science fiction anthology book consists of a series of interconnected short stories that explore the grand scale of the universe and the future of humanity. It spans billions of years, from the birth of the universe to its eventual demise, and delves into various themes such as cosmology, evolution, and the potential fate of intelligent life.
The collection connects the novels of the main Xeelee Sequence together and provides interesting backgrounds, and scientific premises to the universe as a whole. All the stories are wrapped together as being viewed by two individuals (one a man, the other a god) with the Prologue and the Epilogue providing the loose structure for the anthology. The 23 short stories are set within the below human time periods and presented chronically.
- Prologue: Eve
- Era: Expansion
- Era: Squeem Occupation
- Era: Qax Occupation
- Era: Assimilation
- Era: The War to End Wars
- Era: Flight
- Era: Photino Victor
- Epilogue: Eve
Each story is based on a different aspect of humanity’s struggle to understand and navigate the universe and focuses on small actions taken by important individuals throughout the timeline and how their bravery, failures and intelligence affected the evolution of the human species through war, exploration, expansion and the inevitable decline of civilization. From encounters with ancient and immensely powerful alien races to the exploration of alternate universes and the development of advanced technology, the stories weave together to form a comprehensive narrative of human advancement and its consequences.
As the book progresses, it delves into the concept of the Xeelee, an enigmatic and technologically advanced race that plays a pivotal role in shaping the destiny of humanity. The Xeelee and their actions reverberate throughout the stories, leaving lasting effects on the civilizations and individuals they encounter.
The titular story “Vacuum diagrams”, the 15th entry, is set in A.D. 21124 and revolves around the main character’s attempt and failure to terraform a colony due to its upset of the agenda of the galactic-scale builders known as the Xeelee. The book finishes with the novella length “The Baryonic Lords” which tells the story of the last generations of humans.
