After the terrestrial planets and the Moon formed they continued to be pummelled by planetesimals left over from planetary accretion and from the main asteroid belt.
Even though late accretion is well established as having been important in the evolution of the young solar system, its intensity and temporal decline remain subject to debate.
The impact chronology obtained from dynamical simulations is at odds with that of the established crater chronologies.
Here the team use mid-resolution simulations for 2 Gyr of test particles that venture into the inner solar system to compute their impact chronology onto the Moon and Mars, and compare this with established crater chronologies. The team also compare this with the inferred impact intensity on Earth between 3.5 and 2.5 billion years ago.
The primary challenge is to obtain an accurate impact rate for the last 1 Gyr of evolution due to substantial particle loss. We are further challenged by the duration of the simulations versus that of the project.
The main scientific and sociological advance is insight into the dynamical history of the early solar system. The main technical advance is progress in constraining the current computational limits to simulate the dynamical evolution of the inner solar system.
Ramon Brasser, Research Centre for Astronomy and Earth Sciences - Hungary