There is 1 cepheid star that changed the way we used to see the universe, the cepheid variable v1, this important star allowed the american astronomer Edwin Hubble to demostrate that the filmy nebula in wich it lay was, in fact, another galaxy entirely, demostrating that the mily way was not the only thing in the universe and that the universe is expanding!

These variables made us see the universe in a different way and forzated us to expand our knowledge about the mysteries of the universe, beside that it reminded us how little we know about the cosmos

Thanks to the light that we receive from the stars we can know if it is coming closer or further away just knowing the color thanks to the doppler effect that affects the frequency of the light that we see, if it tends to blue it is becoming closer because that is how we perceive the higher frequency and if it tends to red it is becoming further away because of the same reason but in the opposite way