Planck Probe (2)
Based on Magee McKee, New Scientist, 5 October 2013
Recent observations from the Planck probe provide the best picture of the cosmic background radiation. Opinions are divided as to the significance of the recent evidence. Cosmoligists at Princeton view the latest evidence as creating problems for inflation theory, which has for some years been a consensus interpretation of the development of the early universe.
Inflation theory has been used to account for the evenness of temperature across the early universe. This suggested that areas of the universe that are out of range of one another in terms of a signal travelling at the speed of light since the Big Bang must, nevertheless, once have been in contact with one another so as to achieve thermal equilibrium. This puzzle can be solved if there was a very rapid phase of expansion in the early universe, now known as inflation.
Maps of the cosmic background radiation, prior to the latest Planck data, did not have good enough resolution to give much idea of how inflation proceeded. In particular, it was not possible to discern the curve of inflation, whether it was fast at the beginning and slowed down or vice versa. The data now received is inconvenient for the theory in suggesting the rate was fairly constant without any noticeably faster patch. It is inconvenient because such a constant rate model requires fine tuning. In particular, the universe needs to start with an improbable degree of smoothness, relative to the infinite number of possibly rougher states that could have been present. Such a model has been described as ‘exponentially less likely’. There is also some difficulty in reconciling inflation theory with the energy level now known to apply to the recently discovered Higgs boson. Possible adjustments of the theory to deal with these problems have been suggested, as by the physicist, Andrei Linde, but have in turn been criticised as constituting reverse engineering.
Further to this, the data provides no indication of the infinite number of universes that have been suggested to bud off during inflation. What has, however, been observed is a giant cold spot, suggested by some physicists to be an interaction with another universe. However, the data does not appear to be consistent with the creation of an infinite number of parallel universes. One reason for the popularity of inflation theory was the idea that an given an infinite number of universes with different physical laws, it was inevitable that one (ours) would have physical laws that were sufficiently fine tuned to allow for the emergence of intelligent life. This would resolve the underlying problem that if the physical laws were even very slightly different from what they are organic life would be impossible.