not sure this is new... if I remember correctly our galaxies arms rotate along their length and cross each other every (approx) 140 million years which disturbs

not sure this is new... if I remember correctly our galaxies arms rotate along their length and cross each other every (approx) 140 million years which disturbs our kuiper belt which dislodges numerous items which rain down destruction on earth approx 70 million years later, so Jupiter mops up most but not all.