At https://phys.org/news/2019-08-kepler-forgotten-ideas-symmetry-spiral.html … Johannes Kepler was interested in symmetry – in such things as snowflakes as well as in space. Kepler suggested it was due to a morphogenic field. Science, we are told, had subsequently discarded this idea but the question of why snowflakes and similar structures are so symmetrical is not yet properly understood. Symmetry also exists in space – in spiral galaxies for example. A new theory published in Scientific Reports (August 2019) has combined information with entropy related to geometry. They compare the two strands of the DNA double helix winding around each other to light waves that have the same structure, where the two strands are electric and magnetic fields.
Spiral galaxies are double spirals just as DNA is a double helix – mathematically they have similar geometries. They go on to say that in their theory there is no need to invoke dark matter.
