<P> Almost all astronomical objects used as physical distance indicators belong to a class that has a known brightness . By comparing this known luminosity to an object 's observed brightness , the distance to the object can be computed using the inverse - square law . These objects of known brightness are termed standard candles . </P>
<P> Almost all astronomical objects used as physical distance indicators belong to a class that has a known brightness . By comparing this known luminosity to an object 's observed brightness , the distance to the object can be computed using the inverse - square law . These objects of known brightness are termed standard candles . </P>
which two things are needed to determine a standard candle distance from earth
which two things are needed to determine a standard candle distance from earth
By comparing this known luminosity to an object 's observed brightness
By comparing this known luminosity to an object 's observed brightness