I haven't had time to read through all of that yet, but thanks for it. I also found this: http://www.youtube.com/watch?v=Y1brmMNvTY8#t=95s
This is old, but it says that the moons were broken apart completely and reformed, which explains some of their surface features.
If so, then is the presumption that they are from before or after the moon hit it? ie, formed from the debris of the protoplanet that broke up before impact, or formed from the debris that was knocked off the planet from the impact?
How long would this typically take? Millions of years...
One of the leading theories that explains Uranus' tilt is that it was hit early in its lifetime by a protoplanet, which disrupted its rotation axis and caused its unusual tilt. How does this hypothesis explain Uranus' moons as well? Most of them are aligned to the equator, and some are also...
Unless something like "light friction" proved to be true, which was what my original question was about. Since then, I came across http://en.wikipedia.org/wiki/Tired_light" , which explains some of my questions and happens to explain that it probably isn't true. Plus, even though I don't really...
And this is because the cosmo. redshift is dynamic and changing? Is the current spatial expansion rate measurable in a lab? Would it be theoretically possible that the reason that light is redshifting be due to something else such as some unknown frictional force, rather than expanding space...
Astronomers believe that the universe is expanding because of the measured doppler effect redshift of light emitted from distant stars in other galaxies, correct? Do they have other reasons for believing that the universe is expanding? The stars in our own galaxy are known to not be traveling...