Wormhole

Basic Information

A wormhole is a hypothetical topological feature of spacetime that is basically a 'shortcut' through space and time. Spacetime can be viewed as a 2D surface, and when 'folded' over, a wormhole bridge can be formed. A wormhole has at least two mouths which are connected to a single throat or tube. If the wormhole is traversable, matter can 'travel' from one mouth to the other by passing through the throat. While there is no observational evidence for wormholes, spacetimes containing wormholes are known to be valid solutions in general relativity. Various scientific principles refute the practicality of such wormholes, however, as most wormhole solutions to spacetime are unstable and it is expected they would collapse before you can travel through them. Some of the more exotic wormhole equations do seem stable, however, so it's not ruled out entirely just yet. Creating such a wormhole would likely take more power than currently produced on the earth but may be possible at some future date. Such a gate may require the presence of a physical (mega)structure such as a hyperspace gateway … or it may not.

The name "wormhole" comes from an analogy used to explain the phenomenon. If a worm is traveling over the skin of an apple, then the worm could take a shortcut to the opposite side of the apple's skin by burrowing through its center, rather than traveling the entire distance around, just as a wormhole traveler could take a shortcut to the opposite side of the universe through a topologically nontrivial tunnel. (See also Riemann's Bookworms). The rest of the universe goes around the apple, but you can tunnel through it.

In addition to just moving you through space, a wormhole may connect to a different time, another dimension or parallel universe. Any or all of these variations could exist within a setting, and some or all may not be possible, as well. And then there's ways to use one sort of wormhole as if it were a different type:

• A series of spatial (not temporal) wormholes, known as a Roman Ring, can function as a limited Time Machine. On their own, none violate causality, but chained together, they do.
• Another idea is that if you had a spatial wormhole whose ends were mobile, you could make a time machine out of them via a variation on the Twin Paradox. You send one end away at relativistic speeds, and then bring it back. After it returns, the two openings connect to roughly the same place at different times.
• A wormhole called the Einstein-Rosen Bridge exists at the heart of a Rotating Black Hole, it's likely to open into a Mirror Universe.

Sources

Bibliography

1. Wikipedia article

2. Non-Fiction: Hyperspace by Michio Kaku

Game and Story Use

• Adventure Seed: Caverns of Chaos
• The science fiction version of a Portal to the Past, time-crossing wormholes allow you to insert a time travel subplot while giving the heroes next to no control over the time travel.
  • Also, those who traverse a wormhole may not immediately realize that they have traveled through time as well as space.
• Long-distance wormholes make for natural choke-points of great strategic value.
• Wormholes can allow people to cross large astronomical distances without the use of faster-than-light technology.
  • Wormhole creation may itself be a form of (de facto) faster-than-light technology.
    • Creating one is likely to take enormous energy, you'd probably need a high Kardashev Scale rating.
    • If an alien species or civilization has developed stable Wormhole production, the universe may be riddled with shortcuts.
    • Imagine a "Wormhole Bomb" that creates a wormhole to a random part of the universe. There's no telling where it will open up into, what you'll find there. If the technology includes some way of making sure it doesn't swallow your homeworld, this method could be used to explore space in a very haphazard fashion - but random space exploration is probably better than taking generations to get anywhere interesting.
      • Of course, it might still take generations, as most of space is empty. Yes, you'll have a door to the far reaches of the cosmos, but there's a very good chance it'll be an empty corner of the far reaches of the cosmos. If you can figure out a believable way to hand-wave over that hurdle, however, then you're looking at a very unique method of exploration that could make your campaign memorable.
    • It's also possible that you need construction/energization/detonation/etc at both ends of the wormhole in order to create it. In this case, someone has to travel great distances via slower-than-light craft in the first place, so that others can zip over the end later. Such a setting may have numerous shorter wormholes daisy chained, as they were used to resupply the wormhole-cutting deep space vessel.
    • This is played out to a significant degree in the plot to The Expanse
• A wormhole might be a way for three-dimensional humans to out-race or compete with creatures from the Fourth Dimension.
  • Or just be annoyed by them - see also, The Expanse