The photons left over from the Big Bang fill space in all directions. And so they should. Any variations ought to be entirely random since the universe must be the same everywhere. There can’t have been favoured regions of space in the Big Bang, at least not as far as our current theories are concerned.
So when cosmologists found that the variations in the background radiation were not distributed randomly but seemed to be imprinted with a pattern, more than a few of them scratched their heads in bewilderment.
Now H N Sharpe, an independent researcher in Bognor, Ontario, Canada, suggests that this pattern–called the quadropole moment–may not be a property of the background radiation at all. Instead, the cause may be much closer to home.
Sharpe says the culprit is the Solar System’s termination shock where the outflowing supersonic wind from th Sun is slowed to subsonic speeds by interstellar winds.
The Voyager 1 and 2 spacecraft crossed this boundary in 2003 and 2007 respectively. Last year, scientists studying the data the spacecraft returned noticed that, far from being spherical as had been expected, the termination shock is asymmetric, distorted by some unknown forces.
The termination shock is a thin region of space in which there is a sharp change in the pressure, temperature, density, magnetic and electric field properties of space. That sound like anything familiar? It should. In effect, the termination shock is a giant lens that ought to refract electromagnetic radiation passing through it. Any distortion of this lens could then be seen by observing isotropic radiation passing through it. Sharpe calls it a dirty lens.
Interesting idea and one that Sharpe says can be tested. The shape of the termination shock depends on the solar wind. Any changes in this wind should cause the termination shock to change shape, causing an equivalent change in the pattern imprinted on the microwave background.
And sure enough, Sharpe says astronomers have reported just such a change between two sets of images taken by the WMAP spacecraft, called the WMAP3 and WMAP5 maps.
That could set the cat among the pigeons.
Ref: arxiv.org/abs/0905.2978: A Heliosheath Model for the Origin of the CMB Quadrupole Moment