People can study earth science online through Study.com, Academic Earth and MIT Open Courseware. These courses are open to anyone and cover a variety of topics within the earth science category.
Study.com has a searchable list of courses that can be refined by type, such as astronomy or geology within earth science, to find specific courses. Each course has numerous lessons in the form of videos and slideshows, exams and a syllabus. The site has a temporary free trial for users to test out the system, but it also offers paid options that offer college credit.
Academic Earth has a smaller number of courses available, but each course has multiple video lessons sourced from affiliated universities. The site hosts a tool where users can search for online colleges to find more course options or work toward a degree.
MIT Open Courseware is a collection of undergraduate and graduate level courses, many of which are in the earth science category. The courses are not video-based; instead, they offer downloadable lesson notes, exams, course materials and other items used in the class. Each class is an online version of a class that was taught in a prior school year by an MIT professor.