Source: https://twitter.com/Aviation_Intel/status/1142532802237194240
Tyler Rogoway raises and interesting suggestion, that the “cube in a sphere” things that have been reported are actually some form of radar reflector. Weather balloons and boats have radar reflectors made of three intersecting planes of metal or metal coated material. The corners are “retroreflective” meaning they show up really well on passive radar systems.
He found an old patent ... Read even more