Solving three solar system mysteries at once

Solving three mysteries at once (May 25)
http://physicsweb.org/article/news/9/5/17
Planetary scientists have developed a theory that can explain three
outstanding puzzles about our solar system: Why do the giant planets
have eccentric and tilted orbits? How did Jupiter get its Trojan
asteroids? And what caused the Late Heavy Bombardment some 700 million
years after the Earth and Moon were formed? The answer seems to be that
all three phenomena seem to be a direct result of Saturn and Jupiter
shifting their orbits in the early solar system.