Planet Nine difficult to otherwise explain. "The amount of warp we see is just crazy," she said. "To me, it's the most intriguing evidence for Planet Nine I've run across so far." American astrophysicist Ethan Siegel, who is deeply skeptical of the existence of an undiscovered planet in the Solar System, nevertheless speculates that at least one super-Earth, which have been commonly discovered in other planetary systems but have not been discovered in the Solar System, might have been ejected from the Solar System during a dynamical instability in the early Solar System. Planetary scientist Hal Levison thinks that the chance of
Five-planet Nice model in 2011 after numerical models indicated that this is more likely to reproduce the current Solar System. The following is a version of the five-planet Nice model that results in a late instability and reproduces a number of aspects of the current Solar System. The early Solar System may have evolved differently, however, with the instability occurring soon after the dissipation of the gas nebula, or with the giant planets beginning in another resonance chain. The Solar System ends its nebula phase with Jupiter, Saturn, and the three ice giants in a 3:2, 3:2, 2:1, 3:2 resonance chain with semi-major