But that fifth giant, perhaps as big as Neptune, perhaps only half that size, went too close to Jupiter — or Jupiter went close to it — and the nameless world was whipped out into space at a screaming 200,000 m.p.h. (322,000 km/h) or so.
Very likely, as JUNO spacecraft approaches Jupiter in 2016, it should reach a speed in excess of 160,000 mph, though I thought I read somewhere speeds as high as 200,000 mph. Don't get too close to Jupiter if you don't know what you're doing.


), but I have seen at least two threads about this. 