Two versions ofthis quantity, one of which can change over time and the other which is constant, are related by the (*) scalefactor; those are the co-moving and proper versions of it.
This quantity is equal to 10 to the power quantity apparent magnitude minus absolute magnitude plus 5,all over 5, and the difference between the apparent and absolute magnitude is often called the modulus ofthis quantity. Baryon acoustic oscillations provide a standard for measuring this quantity. Two versions ofthis quantity, one of which can change over time and the other which is constant, are related by the (*) scalefactor; those are the co-moving and proper versions of it. Leavitt's fixed period-luminosity relationship for Cepheidvariables allows their use for measuring this quantity. Measures of this quantity are calibrated using stellar parallax.The radial velocity is equal to this value times the Hubble parameter according to Hubble's law, which is used torelate it to redshift. For 10 points, name this parameter which is measured in parsecs and light-years.
This quantity is equal to 10 to the power quantity apparent magnitude minus absolute magnitude plus 5,all over 5, and the difference between the apparent and absolute magnitude is often called the modulus ofthis quantity.
distance [accept things like "how far away things are" or equivalents]