  Terrestrial planets are thought to be the result of a vast number of
gravitational interactions and collisions between smaller bodies. We use
numerical simulations to show that practically identical initial conditions
result in a wide array of final planetary configurations. This is a result of
the chaotic evolution of trajectories which are highly sensitive to minuscule
displacements. We determine that differences between systems evolved from
virtually identical initial conditions can be larger than the differences
between systems evolved from very different initial conditions. This implies
that individual simulations lack predictive power. For example, there is not a
reproducible mapping between the initial and final surface density profiles.
However, some key global properties can still be extracted if the statistical
spread across many simulations is considered. Based on these spreads, we
explore the collisional growth and orbital properties of terrestrial planets
which assemble from different initial conditions (we vary the initial
planetesimal distribution, planetesimal masses, and giant planet orbits).
Confirming past work, we find that the resulting planetary systems are sculpted
by sweeping secular resonances. Configurations with giant planets on eccentric
orbits produce fewer and more massive terrestrial planets on tighter orbits
than those with giants on circular orbits. This is further enhanced if the
initial mass distribution is biased to the inner regions. In all cases, the
outer edge of the system is set by the final location of the $\nu_6$ resonance
and we find that the mass distribution peaks at the $\nu_5$ resonance. Using
existing observations, we find that extrasolar systems follow similar trends.
Although differences between our numerical modelling and exoplanetary systems
remain, we suggest that CoRoT-7, HD 20003, and HD 20781 may host undetected
giant planets.
