Charles Cockell, who teaches "astrobiology and the search for extra-terrestrial life" at Edinburgh University, told The Scotsman he was astonished by the geographical diversity of students attracted to the course.
Those eager to learn about life on other planets -- from the comfort of their earthly homes -- include high school students, retirees in their 80s and all kinds of people in between.
"The most gratifying thing is there have been study groups forming in India, China, Pakistan, Canada, the (United States) and all over the place," Cockell said. "There's even an astrobiology group in Kosovo."
Cockell said the course includes lectures on how life began on Earth, whether it could evolve on other planets in the solar system and, at the end, a discussion on the possible consequences of discovering life on other planets.
Edinburgh is the first British university to offer free at-home courses through Coursera, based at Stanford University in California.