Archival images snapped by the Hubble Space Telescope revealed the unusual event An artist's concept of comet 41P as it approached the sun, turning some of its ice into gaseous jets NASA / ESA / CSA / Ralf Crawford (STScI) Comets are unpredictable objects. Scientists struggle to forecast the paths and brightnesses of these icy space rocks. Now, an astronomer has caught something especially strange: a comet possibly flipping its rotation. The observation was described on March 26 in the  Astronomical Journal . Nine years ago, comet 41P/Tuttle-Giacobini-Kresák—41P for short—dramatically slowed its spin. Researchers reported that in early 2017, the comet took about 46 to 60 hours to complete one rotation, more than twice as long as its previous roughly 20-hour spin.  Comets do sometimes change their rotation rates, but usually by mere minutes.…