"Provocative..."

Yeah, but nowhere near as provocative as the Solar system crossing the galactic plain and picking up a bunch of wild hitchhikers. We know there is a galactic plain, and reason dictates this region to be heavily populated, far denser than what the Solar system is currently passing through. Also, the Solar system will periodically pass through regions of dense particle matter. We are currently in the bubble of relatively clear space.

This same bombardment affected the entire inner solar system, producing thousands of impact craters on Mercury, Venus, the Moon and Mars. Most of the craters in the southern hemisphere of Mars were produced during this event.



[ ... ]

Also, the event is recorded in the asteroid belt, as witnessed by the meteoritic fragments that have survived to fall to Earth today.




Late Heavy Bombardment was asteroidal, not cometary
Geology News
Monday, March 4, 2002

A pretty active 5th planet, I’d say.

“While many of the talks in this session are based on data and observation, this talk is entirely anchored in the realms of fantasy," John Chambers of NASA's Ames Research Center lightheartedly forewarned at the 33rd Lunar and Planetary Science Conference on Monday. Still, a captive audience listened as Chambers presented rationale he and his Ames partner Jack Lissauer had assembled to describe this fantastic "Planet V."

“Science” reporters...

They almost froth at the mouth every time an astro-scientist speaks -- and if he mentions that his “novel” idea is based on pure “fantasy,” they’re mesmerized all the more.

Next they’ll be saying that scientists actually read science fiction!

On the other hand, please bear in mind that none of this will amount to a hill of beans if hard evidence of a 5th planet is ever discovered. At the moment, though, and as John Chambers very clearly states, this is merely a lesson in thinking out loud, with no supporting data.

Might make an interesting book, though.

Hmm-m...
Dan