Long-term simulations show that close encounters between the minor planets Ceres and Vesta could affect the Earth's orbit.
The two bodies also have a significant probability of impacting each other, estimated at 0.2% per billion year.
Last but not least, Ceres and Vesta gravitationally interact with the Earth, whose orbit also becomes unpredictable after only 60 million years. This means that the Earth's eccentricity, which affects the large climatic variations on its surface, cannot be traced back more than 60 million years ago. This is indeed bad news for Paleoclimate studies.
This unexpected discovery comes at a time when both objects are the targets of the NASA/Dawn mission. The Dawn probe will encounter Ceres in February 2015. Dawn's flyby of Vesta occurred on Saturday, July 16, 2011.