- The young basins represent an epoch of late (~700My) heavy bombardment of the Moon
- There has been controversy of whether these basins represent:
- The tail end of terrestrial planet accretion.
- A spike in the impact rate.
- Based on dynamical simulation, Bottke et al. (2007) argued that it is unlikely to be (1).
- It would be useful if this were confirmed with real data.
- If spike, then the orbits of the planets had to change at 3.9Ga.
- The Nice model is the most successful to date at explaining the LHB observations.
- LHB caused a dynamical instability in the orbits of Uranus and Neptune.
- It can also explain many of the characteristics of the outer Solar System.
This talk can be found at www.boulder.swri.edu/~hal/talks.html
We are grateful to NASA's NSLI, Origins, and OPR programs for support.