I couldn't find anything in the FAQ, but I'm curious about the magic behind how badges are given out.
You are given one by another user. The idea is they empower your audience to raise the visibility of noteworthy content.
You earn the ability to grant badges by posting content that is shared. That wheel counts down how many dots you have towards a badge. Mine says "46" because i haven't given out 46 of the 146 badges i have accumulated to grant.