Among all the services that can be rendered to science, the most important is the injection of novel ideas.

J. J. Thomson


What we need is imagination. We have to find a new view of the world.

Richard Feynman




New ideas are the stuff of science. Without a constant supply of them--clay pigeons catapulted into the blue sky to be shot down-- science would be impossible. As cosmology consultant of "New Scientist", I often come across ideas that blow my mind, that leave my head spinning with their far-reaching ramifications. Like the notion that time could actually run backwards; or that there might exist multiple realities playing out all possible histories; or that our Universe may have been created as a DIY experiment by superior beings in another universe!

Invariably, such ideas are attempts to answer the big questions in science. What is time? What is reality? Are we alone in the cosmos? Where did the Universe come from? Like nothing else, these questions expose the limits of our current knowledge, highlighting the key things scientists at the frontier are wrestling to understand.

What follows are my despatches from the frontier of the imagination. At first sight, the ideas may seem crazy. But, then, once upon a time, the idea that time slows down for someone travelling fast or in the presence of gravity seemed crazy. Now, "time dilation" can be demonstrated with super-accurate atomic clocks and nobody seriously doubts it. Once upon a time the idea that an atom could be in two places at once--the everyday equivalent of being able to sit down and stand up at the same time--seemed crazy. Now, not only is this easily demonstrable but inventions which exploit the ideas of "quantum theory" are estimated to account for 30 per cent of the GDP of the United States.

"Craziness", therefore, is not necessarily grounds for dismissing an idea. Nature is under no obligation whatsoever to respect our sensitivities and behave in a way that appeals to everyday common sense. "Your idea is crazy," the great physicist Niels Bohr is reported to have told a colleague. "The question is: is it crazy enough to be true?"

Of course, the scientific imagination must work within the limits of the known facts. And there is evidence for all the ideas presented here. This book is a tribute to extraordinary people with extraordinary ideas. It's a salute to those with the courage and imagination to try and make tomorrow's science. It's a homage to those who are struggling to see beyond the edge of the known universe.

I hope that in reading this book you will get some feeling of what a wonderful, weird, wacky universe we find ourselves in-- a universe far stranger than anything we could possibly have invented. And I hope that it gets you thinking. Without further ado, then, and in the words of e. e. cummings: "Listen, there's a hell of a good universe next door: let's go!"