Chaotic solar system formation

Two planet formation simulations with slightly different initial conditions. Starting with thousands of planetesimals orbiting the sun, we speed up the movie otherwise it would take years to watch - this is 100 million years in one minute! The number of planetesimals decreases as they collide and and merge together, forming larger and larger objects (denoted by the symbol size). As we speed up the movie you see the time averaged elliptical orbits of the planetesimals. Towards the end we slow time down again. Yellow indicates objects too close to the sun to have liquid water, green are objects in the 'habitable zone' and blue are objects so far from the sun that all water would be frozen. These two simulations diverge such that the lower system forms more slowly and ends up with two small planets in the habitable zone, whereas the upper system ends up with one massive habitable planet with 3x the gravity and a longer year.