Strung up

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Independent
The recent discovery of two lookalike galaxies has led physicists one step closer to finding the ultimate theory of everything, says Marcus Chown
02 March 2005


Could two lookalike galaxies, barely a whisker apart in the night sky, herald a revolution in our understanding of fundamental physics? Some physicists believe that the two galaxies are the same - its image has been split into two, they maintain, by a "cosmic string"; a San Andreas Fault in the very fabric of space and time.

If this interpretation is correct, then CSL-1 - the name of the curious double galaxy - is the first concrete evidence for "superstring theory": the best candidate for a "theory of everything", which attempts to encapsulate all the phenomena of nature in one neat set of equations.

Superstring theory views the fundamental building blocks of all matter - the electrons and quarks that make up the atoms in our bodies - as ultra-tiny pieces of vibrating "string". And, just as different vibrations of a violin string correspond to different musical notes, different vibrations of this fundamental string correspond to different fundamental particles. The problem with string theory is that the strings are fantastically smaller than atoms and, therefore, impossible to detect in any conceivable laboratory experiment. But recently, physicists realised that the extreme conditions that existed in the early universe could have spawned enormously big strings. It is one of these "cosmic superstrings" that some believe is passing between the Earth and CSL-1, and, in the process, creating the curious double image of the galaxy.

The realisation that big strings are possible has come from exploring the most esoteric implications of the theory. For instance, the only way strings can vibrate in enough different ways to mimic all the known fundamental particles is if the strings vibrate in a space-time of 10 dimensions. Since we appear to live in a universe with a mere four dimensions - three of space and one of time - string theorists have been forced to postulate the existence of six extra space dimensions "rolled up" so small we have overlooked them.

http://news.independent.co.uk/world/science_technology/story.jsp?story=615886