What Jobs are they that involve planets?

Most of the jobs would be in the fields of astronomy or physics and require a PhD in one of those subjects. Those would be research jobs, and would be called planetary scientists. As it deals with very nearby objects, they would NOT be cosmologists (who deal with the universe and things very far away in general). Without a PhD, you could work as a data analyst for a large group at a national lab, observatory, or NASA that does planetary work with a bachelors or masters in physics, astronomy, or computer science, or help build spacecraft and other planetary mission equipment with an engineering degree (aerospace, electrical).