Mathematically, these are cycles that produce beat frequencies of which one is a " reduction " of frequency ( see heterodyne ) and it is a sum of their paired absolute frequency differences, giving us a recurrence every 1 / abs ( abs ( ( 1 / 399 )-( 1 / 378 ) )-abs ( ( 1 / 370 )-( 1 / 367 ) ) ) days or about every 23 years ( ~ 8536.5 days ), which is too frequent to be notable .-talk ) 15 : 20, 15 February 2015 ( UTC)
