Why galaxies rotate. The causes of gyration of galaxies are not erected till now. Unified Theory of Nature uncovers this riddle (Formation of galaxies  and Space vortex changes  see). The original cause of their gyration is fundamental property of Universe (Space and World see) – the dissimilarity of the material Space in its various places. This dissimilarity inevitably leads to violation of the spherical symmetry of fluxion of ether to the field with the depressed meaning of its density. The effect is the transmutation of the radial directional fluxion into the tangential to this central region. The last is the basic attribute of any gyration.

Where spiral galaxies rotate.   The ones astronomers consider galaxies rotate by the extremities of branches forward, the others on the contrary. And only about one galaxy NGC 7331 the  answer is unequivocal – the extremities back.

The Unified Theory discovers that the spiral galaxies do not rotate in any way.  Galaxies flow by ether streams  from the outside extremities of  branches to kern ("Formation of galaxies" see above).  A kern only rotates in the indicated direction.

Why galaxies rotate slowly. The causes of slower gyration of the wrong, the elliptic and the globe galaxies are not known. Unified Theory of Nature uncovers this secret.

Elliptic galaxies are the subsequent (to the spiral galaxies) phases of smoothing of density of ether in the presence of the actively reeled jets in the macrovolumes of Universe (Kinds of galaxies see). Then it is obvious that the velocity of flow of ether in the former less dense macrovolume (and now in the present elliptic galaxy) decreases because of smoothing of densities of these macrovolumes. The virtual  ("Where spiral galaxies rotate"  see above) velocity of gyration of a galaxy accordingly decreases also in the process of transiting of the phases of her life from the spiral to the globe.

The wrong galaxy, as appears from Unified Theory of Nature (The gear of occurrence of explosions: Consequence see), is the subsequent (to a globe galaxy)  phase of modification of a galaxy. It is the phase of explosion of the slowly rotating galaxy. Therefore it and is the wrong, therefore it and rotates slowly.

Whence  occurs  the differential circumrotatory speed of the various parts of a spiral galaxy? Observations show the spiral sleeves of galaxies rotate as a unit with a constant angular velocity. By that the various parts of the galaxy rotate with the different velocity – the galaxy interior rotates as a rigid body, but behind its limits the gyration angular velocity decreases in process of approach   to the  edge of a galaxy. The scientific explanation is no to the specified singularities of movements in a spiral galaxy.

A.King [18, p. 107] about it exclaims: «… how the differential circumrotatory generally supposes the existence of the spiral sleeves?! The hard curling should be of the sleeves for one galactic turnover».

From  Unified Theory of  Nature ("Formation of galaxies" and  "Space vortex changes"  see above) follows this fact does not contain inconsistencies, as the observable process  –  is not the circumrotatory of the parts of a galaxy, but the fluxion  of ether to organised of it the kern of a galaxy. The velocity of this fluxion progressively  is increased (The velocity grows to the central region see) as approaching  to the central part.