Mars had been compared to Earth many times in the past, considering the presence of ice caps as well as the similar rotation periods & axes.

Mars - the last planet of the inner solar system & the least dense of its rocky neighbors was carved out by both meteoroid impacts & geologic processes that dissipated long ago.

For those precious view who got to meet the Moon by the soles of their shoes, more details were able to be seen. Hard megaregolith rested beneath the lunar dust as bedrock.

The Moon - Earth's closest companion in the solar system & the fifth largest natural satellite around. Without any prevalent atmosphere to speak of, the craters, regolith & frozen oceans of lava laid bare to those who viewed it from the dense planet.

It also created a potent magnetic field - stronger even than the one surrounding Saturn. Earth had an easier time protecting itself from the solar wind than a much more massive gas giant. In fact, it was structured like that of Jupiter's, armored with radiation belts.

The Earth - a world unmatched in geological vigor, atmospheric variability & miraculous recovery. Outsiders may have called it a pale blue dot, one light of many orbiting a golden star, maybe something unremarkable compared to its kin. We, for thousands of years and counting, have called it home.

Down on the surface, it would get so hot that bismuth & lead sulfides wouldn't be able to condense beyond mountaintops, creating a frost-like appearance.

Venus shares similar densities, masses, iron cores & sizes to its oceanic kin. It also has a geologically active surface & interior, all with mountains, valleys, volcanoes & rather few impact craters. However, any Earth-born organism would perish in seconds upon the second planet from the Sun.

In fact, after billions of years since its creation, it is still partly molten & responsible for generating a magnetic field weaker than Earth's but twenty times stronger than Venus'. It's enough to keep the ionizing solar wind at bay.

Mercury - messenger to the heavens & all those who inhabit it, a small body which boldly faces the sun, the first planet to note whenever one seeks to relay about the solar system.