 As predicted beforehand , the collisions generated enormous waves that swept across Jupiter at speeds of 450 m / s ( 1 @,@ 476 ft / s ) and were observed for over two hours after the largest impacts . The waves were thought to be travelling within a stable layer acting as a waveguide , and some scientists thought the stable layer must lie within the hypothesised tropospheric water cloud . However , other evidence seemed to indicate that the cometary fragments had not reached the water layer , and the waves were instead propagating within the stratosphere . 
