There's room for another planet between Mars and Jupiter. Given that planets formed everywhere else, why couldn't another planet have formed there?

That's Mars. And over there, that is Venus. What a treat - two planets in the same sky.

Visibility remains limited, and this should come as no surprise, given that our customers' visibility is limited,

The chemical and isotopic composition of the sun is the starting composition from which all planets formed.

We here on Earth have long held a fascination with the planet Mars.

This companion is probably too massive to have formed the way we believe that planets do, namely from a circumstellar disk of gas and dust when the star was young. This finding suggests that a diversity of processes act to populate the outer regions of other systems.