terious Star The strange dips, dives & dimmings of an otherwise ordinary star defy most - but not all - explanations. CREDIT.RIG H T X X X X X X X X X X X X X X X Here's what's on the table. in the Galaxy COMET COLLISION Comet or asteroid smash-ups, either in the Tabby's star system or (less plausibly) our own, could produce starlight-blocking clouds - one possible explanation for the odd behavior of Tabby's star. N AS A / J PL- CA LTEC H / R . H U RT ( I PAC) s k y a n d t e l e s c o p e .c o m * JUNE 2017 17