Final answer:
A galaxy with a redshift of z = 0.1 is moving away from us at 10% the speed of light, not exceeding the speed of light due to the expansion of space itself.
Step-by-step explanation:
If a galaxy shows a redshift of z = 0.1, this means that the wavelength of light coming from the galaxy has increased by 10%, which indicates that the galaxy is moving away from us. The value of the redshift (z) is linked to the velocity of the galaxy away from us (v) relative to the speed of light (c) through various equations such as Hubble's Law and the relativistic Doppler effect, though for smaller values of z, the relationship can be approximated by v ≈ zc.
Given the redshift z = 0.1, it can be said that the galaxy is moving away at c times z, or 10% the speed of light. This is far less than the speed of light itself, and certainly not greater, remaining within what is physically possible, according to our current understanding of the universe.
It is crucial to understand that the recession speed represented by the redshift is a result of the expansion of space itself, not the motion of the galaxy through space.