speed of light is constant

if the speed o flight is constant......and doppler shifts are based on relative differences in veolicty......how can blue or red shifts occur?

whether the light source was moving away or towards us the velocity of light would still be measured as the same constant value, so how can this constant value be used to measure different distances for different stars? The velocities should be the same in each case....

if this were true then surely the same distance would be obtained every time?

The doppler effect doesn't change the velocity, only the wavelength.

I don't think it's constant. It's affected by gravity passing stars, therefore it may under conditions which we can't experience here on earth slow, or speed up.

Worth some research I'd say

doesn't matter, i was pretty tired when i wrote that, lol

after doing a bit of research, it is the change in frequency that is used, not the change in velocity, and although the speed of light is constant, due to the laws of electormagnetic radiation, the frequency, wavelength and everything else apart from the speed can change.

oh well, lol