Twenty-two years of X-ray timing suggest the disk around pulsar 4U 1626−67 may have flipped from rotating backward to forward in 2008, turning years of spin-down into spin-up — though the evidence remains indirect.

A state-space analysis of 3,340 pulse-frequency measurements slightly favors a retrograde disk before 4U 1626−67's 2008 torque reversal, but a data gap and weak Bayesian odds keep the result indirect. The post Twenty-two years of X-ray timing suggest the disk around pulsar 4U 1626−67 may have flipped from rotating backward to forward in 2008, turning years of spin-down into spin-up — though the evidence remains indirect. appeared first on Space Daily .