The objects their seeing look a lot like the one's seen from the space station but NASA said they were pieces of ice. From what I've seen the objects seem to be tumbling so I don't think they have a rounded surface like Travis suggested I think they have some shape, maybe star or diamond? if it does, and one side turns in one direction and the other side turns in the other direction it would be able to make those quick moves that they do. These are just my thoughts on something no one's been able to explain.