According to Khan Academy, "Moon Badges are uncommon and represent an investment in learning".
Moon Badges on Khan[]
Some of the most common Moon Badges are probably "Awesome Listener", which users obtain for watching an hour of video on one topic, and "Going Transonic" which is received for quickly and correctly answering 10 skill problems in a row. "Geek of the week: mastery" and "Geek of the week: practice" are also two very common badges the user can earn through exercises.
The rarest and most difficult to get Moon Badges are probably "Fact Checker", which requires the user to have a clarification officially accepted, and "Good Inspiration" for having 10 true spin-offs created from the user's project (code must be changed by the users that spin it off).
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