The following is an excerpt from the chapter:

The discovery of potential black holes in the 1970s and 80s caused some scientists to speculate on the existence of their opposite, white holes. After all, if one was sucking in all that matter there must be another spitting it out again, and it was all supported in Einstein’s equations. The suggestion prompted further speculation that it might be possible to pass between the two holes, perhaps to another place or time in this universe, or to a different universe altogether. The resulting passageways, or wormholes, have become the leading candidate for interstellar travel as Man enters the 3rd millennium and together with other terminology that has found its way into everyday conversation, like spacetime continuum, hyperspace and warp-drive you’d be forgiven for believing it’s all just around the corner.

Sadly the reality is far from black and white. Even if wormholes exist there would be no way of knowing where you might end up, or when. That’s assuming you don’t get fried by cosmic radiation on the way through and the passageway doesn’t collapse on the way. But a bigger problem lies much closer to home in our understanding of “time”.