The discovery of strange anomalous rifts in the space-time continuum in the 26th century, called Chang-Ricci rifts after the scientists who first identified them, ushered in a new and exciting age of exploration and discovery. Although humanity was incapable of travelling faster than light and so travel between the stars took many years, access to new dimensions, with new physics and new inhabitants, was an incredible event.

It quickly became apparent that it was almost impossible to move physical matter from one dimension to another without drastically changing its nature, which in the case of living beings usually proved to be fatal, but scientists and engineers soon developed technology which would temporarily wrap inhabitants of one dimension in a cocoon, or more properly a radiation dose of static energies which preserved them for a time. It's historically unclear whether or not they were assisted in this by beings from other universes.

As mankind explored these new universes and began to grapple with their laws and environments, they encountered many strange races and civilisations. With some they fought, with others - the majority - they traded, and yet others were simply too alien to have any common ground for communication or interaction, and so these were simply noted.

The preservation technology used to travel into other dimensions could also be used to carry items back from those dimensions, impossible machines and physics-defying devices which formed the basis for brisk commerce between the human realm and others. The characteristics of such incredible artifacts varied wildly and were often unpredictable, and yet for all that proved both immensely valuable and incredibly popular.

One thing they all had in common however was that the preservation fields suffusing them would eventually falter and fail, reducing their power incrementally over time and ultimately degrading them to mundane elements of their current universe. Repeated treatments with the protective spectra might extend their lifespans, but eventually they would all end up the same way.

These relics are fiercely sought after and rare, given the danger and difficulty of interdimensional travel (there's a decent chance that travellers will simply be disintegrated when passing through interdimensional portals, an unavoidable consequence of the bizarre and enormous energies unleashed), and incorporating them into existing human-universe technologies has produced some powerful hybrid tech.