Maybe, maybe not. There could be potential ultra-long-period impactors that share a similar origin, and therefore a similar period. Or perhaps crossing the gal

Maybe, maybe not. There could be potential ultra-long-period impactors that share a similar origin, and therefore a similar period. Or perhaps crossing the galactic orbital plane changes the odds. The question of periodicity of mass extinctions (and what, if any, causes there are) is a valid line of inquiry, although there are no clear smoking guns. https://www.theatlantic.com/science/archive/2015/11/the-next-mass-extinction/413884/ https://www.theatlantic.com/science/archive/2015/11/the-next...