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Time Travel in Einstein’s Universe: The physical possibilities of travel
through time by J. Richard Gott, Houghton Mifflin, £25, ISBN
0395955637

ACCORDING to Einstein, it ought to be possible to go back in time to try to
kill your parents before you were born. OK, he didn’t say that in so many words,
but it’s right there between the lines of his general theory of relativity.
Something ought to stop you killing them, so it would be fascinating to watch
history protect itself (see p 26 of this issue).

Time travel is a great tool for approaching relativity without realising
you’re doing something so serious, and Richard Gott has a lot of fun in Time
Travel in Einstein’s Universe. He is one of the few time lords of physics: some
years ago he came up with a way to travel into the past. Granted, it’s a bit
impractical—you have to find a couple of handy cosmic strings—but it
should work if technology ever gets there.

There are probably more physicists working on time travel than the funding
agencies realise. Most do it covertly, camouflaging their research with obscure
scientific jargon, and having a ball while everyone thinks they’re doing worthy
physics. Fortunately, Gott is on the inside, and able to translate the jargon
back into familiar terms.

Gott’s book is informative, well written, and entertaining. It’s not entirely
flawless—if his time machine ever works, I’d encourage him to go back and
save the last chapter for another book, as it doesn’t really fit here. That
would have the added advantage of leaving the reader reeling from Gott’s most
mind-bending idea: the Universe could be its own mother. Great stuff.