Light from an object can be look redder or bluer depending on it's radial velocity. Light from Andromeda is blue shifted because it's head straight for us! Of course we're talking nanometer range shifts, but they are measurable to a high degree of accuracy.

Noted. The Doppler effect never sleeps. Pardon my slowness, I still don't see the connection. Correct me if I'm wrong: Depending on our relative positions on our respective orbits, Pluto gets nearer us sometimes, and tries to distance itself from our petty affairs at other times; it's like a drunken girl who can't make up her mind whether she should get into the guy's car and get it over with already, or go back to the bar and have a few more. However, neither action is fast enough to involve Herr Doppler.

2. Regarding your (both informative and entertaining) point 2: do we see APPARENT and ACTUAL movement as two separate phenomena? In other words, as far as the relative velocities of two objects within one inertial frame of reference are concerned, is Relativity in any way affected by the fact that PERCEIVED motion (light playing tricks on us) and ACTUAL motion are different? ... Cause (yeah, you guessed it) I still don't get it.

I mean, I believe (again, correct me if I'm wrong) it's a KNOWN and MEASURABLE fact that Pluto's gravity does affect Earth, and vice versa. So in some degree we ARE looking at a single ... uh ... indivisible ... inertial frame of reference. Or what? ...

Broin: Would this be a good time and place to talk about the varying speed of light in relationship to time and gravitational influences.

Not yet. Yes, absolutely, but not yet. I'm the slowest ship in the fleet here, apparently, and I'd like to get some things straight first. Pleeeease? ... I beseech you!

Okay, so you're saying that nothing can move faster than light WITHIN an inertial frame of reference, and by "inertial frame of reference" you mean a section of space where ... hmm ... the curvature of space is negligible, while gravity is not - if I understand correctly.

You've made a great point about looking to the west, and then to the east. Dancers make Pluto exceed the speed of light every time they do a pirouette - but that "doesn't count," because the force of gravity between them and Pluto is negligible.

So - correct me if I'm wrong - Relativity is similar to Euclid's geometry in that it only works within certain parameters and does not apply to the entire Universe or even galaxy.