At https://tallbloke.wordpress.com/2018/03/14/astronomers-discover-galaxies… … Astronomers discover that galaxies spin like clockwork, and are in tune with each other. Regardless of whether a galaxy is big or small if you sit on the extreme edge of its disc it would take around a billion years to go all the way round, we are told. By using simple maths you can demonstrate all galaxies of the same size have the same average interior density. You won't find a dense galaxy rotating slowly and a lesser densiity one slower. Likewise, it has been found the edge of galaxies are populated by old and new stars – as well as interstellar gas.
Robert sent in the link https://astronomynow.com/2018/03/14/jupiters-great-red-spot-extending-up… it shrinks/ … Jupiter's great red spot (which is turning into an orange spot) is getting smaller we are told. It appears to be a storm in the atmosphere – but a very long lasting storm if true. It is at the same time moving upwards.
Finally, at https://phys.org/print440149988.html …. evidence has been found that suggests that a type of star formation in the centre of our galaxy is responsible for large gamma ray emission – not dark matter. In other words, the phenomenon does not require the existence of hypothetical dark matter.