geckzilla wrote:I think the resemblance is a passing one only. If the spiral density wave model is correct, not only are the forces involved dramatically different, the particles aren't even taking similar paths. The analogy is potentially very misleading.
I should have put some disclaimer on my post. I think all of the aspects I stated are easily established facts, but you're right, they would urge a conclusion (as analogies do) that the motions really are quite similar. I'll go read some more on density wave theory if I get a chance. If spiral galaxies obey that, then are you saying that typhoons do not
At my current state of knowledge, no, I don't think typhoons fit at all, or only in a very limited sense. Gravity is something that we like to feel like we understand. After all, it is really very simple, at least if you're using Newtonian physics, which is great for most things, including this conversation. Armed with such knowledge, our brains easily make a lot of assumptions about how galaxies work by looking at photos of them. Doing some simulation work quickly checks those assumptions and forces one to reconsider them.
I don't know when exactly I started understanding this. Probably after fooling around for quite a number of hours in Blender with some basic particle physics simulations. If you do some reading, make sure you include some videos. Text really doesn't do it any justice. And make sure they're a variety of videos. I'm not sure there is a single most right answer, or I'd just throw a link your way. Some simulations are more sophisticated than others.