In Search of the Multiverse by John Gribbin

The scales of time and distance that are involved in astrophysics and quantum science can often leave me floundering and disorientated.
The idea that there at least 1,000 billion stars in our own Milky Way and an equivalent number of galaxies, each on average containing a similar numbers of stars to our own, in the visible universe is astounding.
It gets worse when you also have to struggle with the concept that all those suns – and presumably thousands of billions of planet that orbit them as well – all emerged from a point that at one stage was many times smaller than an atom.
It is impossible to conceptualise yet fits in perfectly well with the most up-to-date theories of how our universe began.
However, John Gribbin piles on the conceptual anguish as he theorises that our universe may be just one of many, numbering much more than a mere 1,000 billion. The figure he comes up with is an estimated 1 with 500 noughts after it.
There is no way this can be demonstrated by observation, but the existence of a multiverse stands the scrutiny of science and, according to Gribbin, is a logical outcome of what we know about the physics of our universe.
Alternative universes may be separated from ours by a miniscule spacial distance, although in one of a possible seven other dimensions than the three we are used to as a result of quantum splits.
He also theorises that new universes could be created by black holes in our universe which are in fact gateways to an entirely new universe. Indeed out universe may be the result of a black hole in another universe.
Gribben runs through all the various theories that allow for a multiverse in this immensely readable book.
Although some of the physics that he draws on to back up his arguments was well beyond me he is good at trying to flesh out his ideas in laymans terms.
A glossary at the back explains the recurring scientific terms.
The last chapter was the most bizarre in which he speculates that our universe may actually be the result of intelligent design – not by an omnipresent deity but advanced alien civilisations.
This is not a sci-fi geek writing here but a respected physicist.
Yet he pays homage to those science fiction writers who speculated on such scenarios and about the existence of the multiverse long before it became a viable scientific theory.
Michael Moorcock, one of the few science fiction writers I like (and former poet-in-residence with Hawkwind), gets a nod.
Not mentioned by Gribben, but the best fictional take on his theory that I have read was The Number of the Beast by Robert A Heinlein in which four interdimensional travellers navigate through a multiverse with three spacial dimensions and three time dimensions, creating a total of six which can be raised to the par of six to the par of six... creating a multiverse based on the biblical number of the beast.
Gribben does mention a story called The Garden of Forking Paths by Jorge Luis Borges in which he speculates that each choice made by every human results in a split in the universe and that results in a constantly branching multiverse in which versions of the same people are living a whole series of alternate lives.