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Computations of a poetical universe
The whole universe can be that cold and distant association of matter in a ponderous 10^80 chunk of bits, but Mankind can manage to see it with poetical imagination and describe it as a machine that´s computing its own dynamical evolution. "As the computation proceeds, reality unfolds", says Seth Lloyd, a physicist at the Massachusetts Institute of Technology in Cambridge.
Balls´ article remembers something of the historical context: "Just as clocks were the favourite analogy for complex systems during the age of Newton, now scientists like to compare everything to computers. DNA is sometimes described as digital, and the human brain, consciousness and life itself are discussed as though they all involve computation. So is Lloyd taking it all too far, depicting the Universe as a computer?" It doesn´t seem so if one can consider that although it isn't clear that there is any 'problem' for the Universe to solve, the connection between information science and physical processes appears once we think about events on the quantum scale, as we are reminded in Nature´s article, which ends enforcing Lloyd´s thesis: " He estimated the maximum number of logical operations the Universe has performed by calculating its total energy with Einstein's E = mc2. The energy of any physical system determines how fast it can switch from one quantum state to another - how fast it can compute". This is all rather theoretical, because until now quantum computing has been limited to calculations involving only a handful of bits of information. But two researchers of the University of Bristol, Graeme Mitchison and Richard Josza, invite us to imagine that a quantum computer exists, a fact that would highlight the counter-intuitive nature of quantum physics (see their article in Mitchison, G. & Jozsa, R. Counterfactual computation. Proceedings of the Royal Society London A 457, 1175-1193 (2001). Or, as Richard Josza describes in his article Quantum Effects in Algorithms, written when he was still at the University of Plymouth (1997/1998), a counterfactual effect may be defined as an observable physical effect E whose outcome depends on an event A that might conceivably have happened but in fact did not happen i.e. E is affected by the mere existence of A as a valid possible alternative even though A did not actually occur. That is, "Suppose that we have a quantum computer which has been programmed ready to solve a decision problem. The computer also has an on/off switch, initially set in position off. We will show that in certain circumstances, the mere fact that the computer would have given the result of the computation if it were run, is suffcient to cause a physically measureable effect from which we can learn the result, even though the computer is in fact not run". Reality unfolds as Al Stewart´s Sirens of Titan sing
our destiny: "I was a victim of a series of accidents/as all
we are", and galaxies collide. Says the caption of this beautiful
illustration: "After a head-on collision, the galaxies' shapes
are strongly disrupted. The tidal forces of gravity have created
long plumes of material called 'tidal tails'. The central regions
will relatively quickly fall back together and merge into a single
remnant galaxy. Such a collision may occur for our Milky Way Galaxy
and the neighboring Andromeda Galaxy in about five billion years".
This one and many others at http://oposite.stsci.edu/pubinfo/PR/2002/09/ill/i0209dw.jpg
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"If
one regards the Universe as performing a computation", says
Lloyd, "most of the elementary operations in that computation
consist of protons, neutrons, electrons and photons moving from
place to place and interacting with each other according to the
basic laws of physics." In an article recently published in
the Physical Review Letters, the physicist extends his last
exploits about the constraints that physical laws place on the power
of lesser machines ( a laptop computer, exemplifies a Nature article
by Philip Ball) to a Universe-sized computer that would have to
perform 10 ^120 manipulations of those bits. 
