Fiction:Virgo Birch Planet/Space

Cosmic String
Cosmic strings are 1 dimensional topological defects in space itself. They can have enormous mass, and due to their 1D nature,therefore can have event-horizons. Cosmic strings are essentially indestructable so find use in the reinforcement of many planetary structures that wouldn't be able to support themselves and stabilisation of materials like quarkonium.

Cosmic strings are made by heating a region of space up to temperatures and matter densities close to that of the big bang, often using electroweak superfluid from electroweak stars.

Exotic String
Exotic strings are those that have negative mass rather than positive. They can therefore take the place of exotic matter in many applications such as closed timelike curves and warp drives.

Wormholes
Artificial wormholes that allow the passage of single particles or even whole macroscopic objects over distances that may range from a few meters, to between galaxies. They are integral to the transport of information and resources on such a large planet and form a cornerstone in Birch technology. Wormholes are constructed by taking a naturally occurring wormhole from the quantum foam and stretching it to the appropriate size using exotic string.

Microscopic Wormholes
Signal holes are wormholes specifically for the passage of photon signals. They are smaller than a proton and thus require only the tiniest fleck of cosmic string to keep open and are very hard to detect for less technologically advanced species.

Microscopic wormholes can also allow for the passage of nanobots and other microscopic machines as well as streams of plasma, which allows the free movement of planetary infrastructure regardless of distance.

Large Wormholes
Wormholes can also be engineered to allow the passage of people, ships, or even whole Dyson spheres across vast distances.