Schild's Ladder
Encyclopedia
Schild's Ladder is a 2002 science fiction
novel by Australia
n author Greg Egan
. The book derives its name from Schild's ladder
, a construction in differential geometry, devised by the mathematician and physicist Alfred Schild
. This novel is perhaps the hardest science fiction
ever published by Egan, filled with non-trivial mathematics
and theoretical physics
.
physicist from Earth, travels to Mimosa
orbital station and begins a series of experiments to test the extremities of the fictitious Sarumpaet rules, a set of fundamental equations in "Quantum Graph Theory," which holds that physical existence is a manifestation of complex constructions of mathematical graphs
. However, the experiments unexpectedly create a bubble of something more stable
than ordinary vacuum
, dubbed novo-vacuum, that expands outward at half the speed of light
as ordinary vacuum collapses to this new state at the border, hinting at more general laws beyond the Sarumpaet rules. The local population is forced to flee to ever more distant star system
s to escape the steadily approaching border, but since the expansion never slows, it is just a matter of time before the novo-vacuum encompasses any given object.
Two factions develop as the expanding bubble swallows star after star: the Preservationists, who wish to stop the expansion and preserve the Milky Way
at any cost; and the Yielders, who consider the novo-vacuum to be too important a discovery to destroy.
Six hundred years after the initial experiment, aboard the Rindler, a vessel that has matched velocities with the border, a variety of refugees are probing the novo-vacuum in order to understand the physics that makes it possible. The novo-vacuum turns out to be more complicated than anyone suspects, however, and Egan's usual topics of simulation
and quantum ontology are taken to the extreme when we learn that a whole ordered universe exists within this zone of apparent chaos, existing as direct elaborations of the quantum graph's lattice structure, of which elementary particle
s, fundamental interaction
s, and spacetime
itself are only special cases.
Science fiction
Science fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...
novel by Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n author Greg Egan
Greg Egan
Greg Egan is an Australian science fiction author.Egan published his first work in 1983. He specialises in hard science fiction stories with mathematical and quantum ontology themes, including the nature of consciousness...
. The book derives its name from Schild's ladder
Schild's ladder
In the theory of general relativity, and differential geometry more generally, Schild's ladder is a first-order method for approximating parallel transport of a vector along a curve using only affinely parametrized geodesics...
, a construction in differential geometry, devised by the mathematician and physicist Alfred Schild
Alfred Schild
Alfred Schild was a leading American physicist, well-known for his contributions to the Golden age of general relativity ....
. This novel is perhaps the hardest science fiction
Hard science fiction
Hard science fiction is a category of science fiction characterized by an emphasis on scientific or technical detail, or on scientific accuracy, or on both. The term was first used in print in 1957 by P. Schuyler Miller in a review of John W. Campbell, Jr.'s Islands of Space in Astounding Science...
ever published by Egan, filled with non-trivial mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
and theoretical physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
.
Plot summary
Twenty-thousand years in the future, Cass, a humanoidHumanoid
A humanoid is something that has an appearance resembling a human being. The term first appeared in 1912 to refer to fossils which were morphologically similar to, but not identical with, those of the human skeleton. Although this usage was common in the sciences for much of the 20th century, it...
physicist from Earth, travels to Mimosa
Beta Crucis
Mimosa or Becrux is the second brightest star in the constellation Crux and is one of the brightest stars in the night sky....
orbital station and begins a series of experiments to test the extremities of the fictitious Sarumpaet rules, a set of fundamental equations in "Quantum Graph Theory," which holds that physical existence is a manifestation of complex constructions of mathematical graphs
Graph theory
In mathematics and computer science, graph theory is the study of graphs, mathematical structures used to model pairwise relations between objects from a certain collection. A "graph" in this context refers to a collection of vertices or 'nodes' and a collection of edges that connect pairs of...
. However, the experiments unexpectedly create a bubble of something more stable
False vacuum
In quantum field theory, a false vacuum is a metastable sector of space that appears to be a perturbative vacuum, but is unstable due to instanton effects that may tunnel to a lower energy state. This tunneling can be caused by quantum fluctuations or the creation of high-energy particles...
than ordinary vacuum
Vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
, dubbed novo-vacuum, that expands outward at half the speed of light
Speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
as ordinary vacuum collapses to this new state at the border, hinting at more general laws beyond the Sarumpaet rules. The local population is forced to flee to ever more distant star system
Star system
A star system or stellar system is a small number of stars which orbit each other, bound by gravitational attraction. A large number of stars bound by gravitation is generally called a star cluster or galaxy, although, broadly speaking, they are also star systems.-Binary star systems:A stellar...
s to escape the steadily approaching border, but since the expansion never slows, it is just a matter of time before the novo-vacuum encompasses any given object.
Two factions develop as the expanding bubble swallows star after star: the Preservationists, who wish to stop the expansion and preserve the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
at any cost; and the Yielders, who consider the novo-vacuum to be too important a discovery to destroy.
Six hundred years after the initial experiment, aboard the Rindler, a vessel that has matched velocities with the border, a variety of refugees are probing the novo-vacuum in order to understand the physics that makes it possible. The novo-vacuum turns out to be more complicated than anyone suspects, however, and Egan's usual topics of simulation
Simulation
Simulation is the imitation of some real thing available, state of affairs, or process. The act of simulating something generally entails representing certain key characteristics or behaviours of a selected physical or abstract system....
and quantum ontology are taken to the extreme when we learn that a whole ordered universe exists within this zone of apparent chaos, existing as direct elaborations of the quantum graph's lattice structure, of which elementary particle
Elementary particle
In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not known to be made up of smaller particles. If an elementary particle truly has no substructure, then it is one of the basic building blocks of the universe from which...
s, fundamental interaction
Fundamental interaction
In particle physics, fundamental interactions are the ways that elementary particles interact with one another...
s, and spacetime
Spacetime
In physics, spacetime is any mathematical model that combines space and time into a single continuum. Spacetime is usually interpreted with space as being three-dimensional and time playing the role of a fourth dimension that is of a different sort from the spatial dimensions...
itself are only special cases.