Use of Superlative Adjectives

We use a superlative adjective to describe one thing in a group of three or more things. Look at these examples:

If we talk about the three planets Earth, Mars and Jupiter, we can use superlative adjectives as shown in the table below:

  Earth Mars Jupiter  
Diameter (km) 12,760 6,790 142,800 Jupiter is the biggest.
Distance from Sun (million km) 150 228 778 Jupiter is the most distant from the Sun.
Length of day (hours) 24 25 10 Jupiter has the shortest day.
Moons 1 2 16 Jupiter has the most moons.
Surface temp. (degrees Celcius) 22 -23 -150 Jupiter is the coldest.
When we compare one thing with itself, we do not use "the":

England is coldest in winter. (not the coldest)

My boss is most generous when we get a big order. (not the most generous)

see also Comparative Adjectives