Worm holes span space time, connecting together points in different parts of the universe. Not only do these worm holes span the vast reaches of space, but they also span vast reaches of time. Every wormhole (see the sidebar for a description) connects two points in both space and time - not only can the ends be separated by light years of distance, they can also be separated by years of time. Travelling through a wormhole will move you through time as well as space.

Civilisations have built a great network of wormholes spanning 9 billion years and thousands (millions?) of galaxies. Some of these civilisations are dead, others are still around. Humanity is one of the members of the 6th generation of intelligent civilisations.

The One Time is a vast empire spanning uncounted galaxies and billions of years. It was started by the Yi'klari 9 billion years ago, and has been extensively added to since then. To understand how it spans time as well as space, and why it is called the One Time, requires some explanation.

A wormhole begins life as a small quantum rift, a hole in space-time which connects together two points. Initially, these two points are very close together (maybe an atom's width apart). These holes appear randomly throughout the universe, last for a few micro seconds, then vanish.

Advanced technology can be used to capture and stabilise such a hole though. Once stabilised, the mouth at each end can be grown by building a framework of exotic matter around it. The two ends can be pulled apart, but they are still connected together similar to a pair of Quantum entangled particles. Both ends of the wormhole are the same point in space-time. It is not a tube or a gate which teleports you from one end to the other. They are the same point - just in difference places.

You can see through a wormhole, stick your head through it, through a ball through it, fly a spacecraft through it. You could stick it on the surface of a planet and build a railway through it (this has been done on several worlds).

A wormhole is two dimensional, often circular (though this is a feature of the framework that keeps it open). Only a single face of the hole can be passed through - the back side is a space-time flaw that is impervious to most physical effects.

The surface of the hole does not ripple or glow or look anything other than an empty bit of space. It is impossible to tell that you've just passed through a wormhole except by looking at outside phenomena (i.e. you are now in a different galaxy).

When one end of a wormhole is accelerated and time dilated, so both ends are equally dilated. If the first end stays at home, and the second end is sent to another star system at close to the speed of light, then anyone travelling through the wormhole from the first to the second will travel into the future.