Can a point be absolutely stationary and what is the velocity of the Milky Way relative to such a point?

Question

What is the speed of light measured relative to?

Answer 1

The Speed of Light is measured to any observer, preferably "at rest" or not moving on an intersteller ship. As said above, there is no such thing as absolutely stationary anywhere. Everything in this Universe moves relative to something else. We move relative to the local star systems, they in turn move relative to the galactic center. The galactic center moves realative to the nearby Galaxies, such as Andromeda Galaxy (which in less than 6 Billion years the Milky Way will collide with to form one larger Galaxy). So, everything moves. Even if it looks like it doesn't.

Answer 2

The speed of light relative to any point is constant. It does not change. Depending on whether you are traveling towards the light source or away from it, you will see a change in color shifted to blue or red, instead of a change in speed.

We would not be able to pinpoint an absolutely stationary point should it exist. If you were floating in the middle of space and couldn't see anything around, you'd have almost no way to detect if you were moving. If an asteroid suddenly zipped by you there is no reason not to say that you zipped by the asteroid.

The only acception to this is if you were accelerating towards a strong gravitational source, such as a black hole, at an increasing rate of acceleration. In that case you'd feel yourself being torn apart.

Answer 3

There is no such thing as a stationary point , except in our imagination, therefore the second part of the main question is moot.

The speed is measured relative to the observer in Einsteins thought experiments.

Yours Truly,
Jonnie