Earth seen from space. NASA.

There isn’t another planet in the solar system like Earth. If you were an alien explorer coming into our neck of the galaxy, you’d find a system with four large gas giants, lots of small, rocky objects without much other than rocks, a few larger rocky objects with some ice and four rocky objects with reasonable atmospheres.

A cursory scan of the surface of those last objects would find that two of the four are covered almost entirely in basalt — an iron and m