I had to look it up, paraphrasing from the article below, z is the cosmological redshift, indicating the recession velocity of the object. So smaller z values m

I had to look it up, paraphrasing from the article below, z is the cosmological redshift, indicating the recession velocity of the object. So smaller z values mean closer, large values mean higher, and the farther away it is the faster it is moving away. http://astronomy.swin.edu.au/cosmos/c/cosmological+redshift http://astronomy.swin.edu.au/cosmos/c/cosmological+redshift