Faster Than Light Travel
From Alcubierre drives to traversable wormholes, explore the physics that could one day allow us to break the cosmic speed limit and reach the stars within a human lifetime.
Explore FTLThe "Beyond" section collects speculative space concepts: technologies and futures that are interesting to think about because they sit close to the edge of what physics allows, or past it. Every page below is explicitly a thought experiment. These are not forecasts; they are the questions you end up asking once you take the long view of what a space-faring species might eventually do.
Each concept has a dedicated article exploring the underlying physics or engineering, the plausibility of its near-term and long-term versions, and the open problems that stand in the way. Where an idea needs physics we do not yet have, we say so. Where it only needs a very large amount of time, money, or energy, we say that too.
How speculative is "speculative"
Three broad tiers of speculation run through the section:
- Plausible extrapolation. Concepts that require only more of what we already have. Terraforming, megastructures built of ordinary matter, and large off-world settlements all belong here. The physics is known; the cost and timescales are enormous.
- Physics on the edge. Ideas that use equations we believe in but that require materials, energies, or exotic states that may or may not be realisable. Traversable wormholes, faster-than-light metrics, and certain forms of machine consciousness belong to this tier.
- Beyond-physics thought experiments. Ideas included because they illuminate what we do and do not know. These are closer to literature than to engineering, and we mark them as such.
Reading these articles should leave you better at telling the three tiers apart, even when the next fast-moving headline blurs them.
Terraforming Worlds
The ultimate expression of human ambition: transforming dead worlds into living ones. Learn about the science, technology, and timescales required to create new Earths.
Transform Worlds
Megastructures
Engineering on a cosmic scale: Dyson spheres, ringworlds, and orbital habitats that dwarf planets. These constructs represent the pinnacle of technological civilization.
Think Big
AI & Digital Consciousness
The merger of human and artificial intelligence could unlock immortality and enable consciousness to spread across the cosmos at the speed of light.
Transcend
Alien Civilizations
Are we alone? Explore the Drake Equation, the Fermi Paradox, and what first contact with an alien civilization might look like.
Search for Life
Interstellar Colonization
The ultimate journey: sending humanity to the stars. Explore generation ships, suspended animation, and the challenges of founding civilizations light-years from Earth.
Journey FarCross-links between concepts
Most of these concepts only become interesting when combined. Terraforming a planet is immensely easier if you can first build the megastructure needed to deliver sunlight or shade where you want it. An interstellar colony is a fiction unless something resembling extended human lifespan — whether biological, cybernetic, or digital — is part of the picture. Finding alien life changes how one thinks about every other concept on the list, and especially about whether humans should be optimising for speed (FTL) or for scale (generation ships and O'Neill cylinders).
We try to link between the articles so that reading one leaves you with a map of the others, rather than a single narrow view.
What is not here
Several adjacent topics are not covered in "Beyond" because they belong elsewhere. Current rocket engineering and ongoing missions live in /now/technology and /now/missions. Original science fiction set in a future where some of the concepts below have been realised lives in the Library. Pure physics tutorials with no speculative component are outside our scope.
Last reviewed on 2026-04-24.