earthist

Thank you very much! I think I get it, but before I go off with enough rope to hang myself, let me extend this wave density concept to a couple of other phenomena: Does wave density have a role in the so-called "Pioneer Anomaly?" Does wave density have a role in the formation of planets at the orbital distances (from the sun) they occupy within the solar system? Finally, let me say that I have been wishing for a place to ask questions like this for years. I have tried lots of "Ask the scientist" sites and tried emailing a few scientists directly, and have never gotten answers. Google is wonderful if you know the term you want to look up -- which your answer provided for me. So, thank you, again! Y'all are much needed and appreciated.

I had always assumed that the galaxy's "arms" were more-or-less stable structures. Thus, I assumed that the solar system would more-or-less "always" be located at a given spot in one of the arms, and would spin around galactic center along with the rest of the arm. Lately, I have heard several references to the idea that the solar system actually travels through the arms. I am confused as to why that would be the case. Cursory thinking suggests to me that the same gravitic circumstances that create the arms would be the deciding factor. But I am apparently wrong, So, can anyone please explain a) whether the solar system does actually move through the arms, and b) why this is the case. Thanks!