THE SPINNING UNIVERSE

Wherever we look in space, we see rotating or revolving objects. The moon rotates round the Earth. The Earth rotates on its axis, and with the other planets it revolves around the Sun, which itself rotates with a nione-hour period at its equator, and revolves around the centre of the Milky Way. The galaxy is also believed to be part of a rotating supercluster. Many large black holes rotate, since they are formed from rotating objects, and these rotating black holes are thought to be responsible for quasar emissions and cosmic rays.

Without the rotation of the solar system we wouldn’t exist, because planets wouldn’t have formed. In fact, one might go so far as to say the rotation is, like gravity and electrostatic force, an “ordering principle” which operates against the relentless increase of entropy as the universe expands; and is ultimately responsible for life.

So why is it all rotating? Where is the universe getting all this angular momentum from? This is a fairly important question but it tends to be glossed over in the astrophysical literature.

The fairly obvious answer is that the universe was born rotating, or at least had powerful vortices at its beginning. Because angular momentum is conserved, when it was small and dense it must have been rotating incredibly quickly. This rotation has been passed on to the various objects in the universe as it expanded, while the overall rotation must have slowed very substantially. 

Against

The main argument against a rotating universe is purely theoretical. If there is a preferred direction or axis of spin of the universe (which, it has been shown, must lie close to the axis of spin of the Milky Way) this negates the cherished principle of isotropism in astrophysics, which says there is no preferred direction or orientation in the universe, everything is independent of  location and direction. This is a key foundation element of Einstein's theory.

Personally I do not give a high credence to theoretical objections. Theory can and should be mended if it does not accord with observation.

For

Cosmic anomalies in the background microwave radiation were once suggested as evidence of rotation.

A paper in 1969 by a young theoretical physicist called Stephen Hawking [2] calculated the limits on vorticity from these observations. However, the anomalies were eventually put down to “observational error”.

However , in 2011  a survey of 15000 spiral galaxies by Longo [1] shows a non-uniform distribution of spin direction in spiral galaxies, re-opening the rotating universe debate. 

Why are spiral galaxies spiral?

About 20 per cent of all galaxies are spiral, with the rest taking the form of ellipsoids or exotic shapes. The ellipsoid galaxies consist largely of old stars, but these spiral galaxies are”young” with a great deal of rotational energy - our very own Milky Way is one of these. while So why are these new star-forming galaxies spiral? Why do they take such a specific form?

 

Spiral Galaxy M100, and low pressure system over iceland

  We have suggested they gain their rotation because they are embedded in larger rotating objects. There are many examples of similar spiral structures on Earth, in biology and in meteorology - cyclones.

The photo shows a typical spiral galaxy and a cyclone. One could be forgiven for thinking they are exactly the same object. Fairly clearly, similar forces are at work.  

The spiral structures require both a central force and some sort of lateral shear force. In cyclones the central force is the low pressure gradient while the shear force is the Coriolis Effect, The Coriolis effect is an artifact of the Earth's rotation, a weak "imaginary" force pushing things sideways; it occurs because we are standing in a rotating frame of reference.  The amount of deflection depends on the speed with which the wind  is moving and the latitude - so that fast winds in high latitudes get more deflection and "spin". 

The different direction in which the water goes down the plughole in the northern and southern hemispheres is due to coriolis force. It's actually possible for water to go either way if you give it a slight initial spin, but if you are far from the equator the probability is higher.

When it comes to galaxies the pressure gradient is gravity, pulling the gases in towards the galactic centre. The shear must also be coriolis force, due to the rotating universe. Like the plughole, more of the galaxies will spin counterclockwise in the northern hemisphere of the universe, depending on the declension from the equator of the universe - hence Longo's result.  

strong evidence for a cosmic parity violation in the Universe, as indicated by a statistically significant excess of left-handed spiral galaxies toward the North Galactic Pole and an excess of right-handed in the opposite direction. This also suggests that our Universe has a preferred axis and a net angular momentum. Since angular momentum is conserved this means the Universe must have been born spinning. We can't see outside of our Universe, so we'd have to assume it is spinning relative to other universes in a higher dimensional space. Presumably the Big Bang was spinning initially, and as it expanded, the net angular momentum was dissipated among the galaxies. Now we still see it through the preferred spin direction.  http://www.lsa.umich.edu/physics/directory/emeritus/ci.longomichael_ci.detail

[1] Longo, M J . 2011. Detection of a dipole in the handedness of spiral galaxies with redshifts. Physics Letters B 699:244.

[2] Hawking, S  (1969). On the rotation of the Universe Monthly Notices of the Royal Astronomical Society, 142 :129.