For the first time, a comet may have been caught flipping its spin.
Sometime between April and December 2017, comet 41P/Tuttle-Giacobini-Kresák apparently started twirling in the opposite direction, astronomer David Jewitt reports in the April Astronomical Journal. The simplest explanation, the study says, is that gases escaping from the small comet forced its rotation to slow, stop and reverse.
The kilometer-or-so-wide comet may keep spinning faster in the new direction until it tears itself apart, says Jewitt, of the University of California, Los Angeles. The fatal pirouette demonstrates why small comets — those less than a kilometer wide — are relatively scarce, he says. “They spin up so quickly,