This is a nice course divided into four modules dealing with four main questions: Are we alone in the Universe? How do Stars Evolve and Die? What Exists Outside our Galaxy? What is the Fate of the Universe? Although only 4 weeks long, each module covers at least 15 video lectures, so it would take you a whole day to go through that week's lectures. However, since it's self-paced, there's a higher degree of freedom here. The teaching style was nice, and it covers basics of astrobiology, astrophysics and cosmology, and it's somewhere between an introductory course and an intermediate one (the quizzes aren't that easy). Unfortunately, there are no problems or math assignments, but this may be a positive thing for beginners wanting to experience the wonderful world of astronomy. The forums are a bit desolate, but this seems to be an issue with self-paced courses, too bad. All in all, go for it, there's always something new to learn.