Citizen scientists found more than 1,500 brown dwarves — 'cool worlds' that are more massive than planets but lighter than stars — in our galactic neighbourhood. The discoveries were part of 'Backyard Worlds: Planet 9', a project which recruited more than 100,000 people to scour astronomical data for new 'nearby' objects. Some of the brown dwarves are even among the coolest of their type known — with temperatures close to ...