Interesting paper by Baba et. al. which looks at how the current reconstructions of the Milky Way’s structure might be misled by certain assumptions. High resolution modelling of the Milky Way’s barred-spiral structure indicates it forms and reforms continually, rather than persisting as a static pattern. But our current reconstructions of its structure assume something more circular and less dynamic. There’s some very interesting graphics from the simulations which compare a synthesised image based on the old assumptions from the actual positions based on the dynamic model – the simulated reconstruction is very close to what I’ve seen in previous papers.
Have a look and a deeper read than me, if you want the full details. I’m a visual thinker and I tend to find explaining the eloquence of a picture difficult to put into words to my satisfaction. The simulated Milky Way just seems right, like a real barred spiral. The stately semi-circular spiral arms of traditional reconstructions are rarer in the Galactic Zoo.