For those interested in this and looking for a book in a similar vein, I can recommend 'A Teaspoon and an Open Mind' by Michael White.
It's basically a scientific review of the technologies on display in Doctor Who (UK time-travelling series for any of you who have not seen it) with a serious discussion of whether or not they would be possible now/in the future with our current knowledge.
I bought this in Epub format from the Waterstones shop in the UK for a reasonable price and enjoyed it.
Below is the link to the pbook at Amazon (co.uk)
http://www.amazon.co.uk/Teaspoon-Ope...0687665&sr=1-1
I note some bad reviews there - but, hey, each to their own!