The Red Shift of the Light

Light travels at a constant speed, a. It only has one speed it travels. And so if you know how long the light took to get to you, then you know how far away it is. But since light always goes the same speed, it gets a little tricky because the distance that it's going is actually stretching while it's going through that am. Ah, the bryan, you said it. The answer your question is that they measure the red shift of the light. Cause the longer, as you stretch out light, it shifts it towards the red end of the spectrum. That just happensa ri tei unk out.