Density Waves and the Stability of Galactic Spiral Arms

This animation shows how speeding up and slowing down of the orbital motions of stars in galaxies can lead to stable spiral arms. This animation is not based on a particular physical model of those density waves, but is my "artist conception", to try to illustrate the concept.

Category:

Education

Tags:

• astronomy
• physical
• science
• galaxy
• density
• wave

[loveandbullets07]

whats your definition of stable? able to inhabit life?

[mrg3]

Stable as in you see the shape of the spirals even though there are stars (solar systems) continually moving into and out of the spirals (this is the point of the animation). If the spirals only consisted of the same stars, then the spirals would "wrap up" around the galactic core and would essentially smear out of visibility.

[multidimensional1]

this is incorrect, as is Einstein's E=MC2, he didn't take account of electricity. we live in an electric universe and it is the electric currents that causes the galactic spirals.

[Quailcrossingfarm]

OK - I see what is happening in your animation, but why are there areas where stars entering it slow down and stars leaving it speed up?

Isn't that just as inexplicable as denser bands that do not wrap up? Could it be local gravitational forces that change angular direction when they are in the thick band versus not in the band. It would make them appear to "dart" (move faster therefore, fewer of them) when they go from the "outside" of one are to the "inside" of the next?.

[spiritelemental]

Awesome animation!!! I had the idea to make an animation of exactly what you have here, but never got around to making it. I had it all planned out perfectly in my head but, as with many of my visions, it never leaves the play ground of my mind. :-)