Why do astronomers and cosmologists prefer to use the Distance Modulus instead of -- rather than in addition to -- Bly (billion light-years) or Mpc (mega parsecs)? Being a LOG10 it distorts relative distances. You can find Bly plotted on a graph (but not specified), and even in studies comparing z with distances according to standard candles, you won't find tables listing z alongside metric distances. Why do astronomers and cosmologists prefer to use "temperature" rather than redshift when discussing CMB (cosmic microwave background radiation)? Why not either call it "cosmic temperature background" or specify the length of the microwave? Space being a vacuum, it seems unnecessarily weird to talk of temperature.