The distance between Earth and Mars changes constantly due ... spacecraft intending to orbit or land on the target body e.g. Mars compared to those that are just going to fly by?
In our solar system Earth and Mars are in the box ... gas giants are literally off the chart. The logarithmic scale used initially here allows for an easier comparison of the exoplanets.
Small in comparison to the gas planets found further from the Sun, they also rotate at a more sedate pace and have few moons… The four rocky planets are Mercury, Venus, Earth and Mars.