This is a simulation showing how we may have lost our 5th Gas Giant during the Late Heavy Bombardment ~4.1 billion years ago. It starts off just as Neptune is about to cross the orbit of Uranus and migrate outwards. The 5th giant conversely, was interacting and being severely affected by the gravitational influence of Saturn, migrating inwards and eventually crossing orbits. This is when the simulation starts. The mass of the 5th Giant is thought to be ~10 Earth masses so this is the value used in the simulation. The orbit order is measured by Semi-major axis, not by it's Aphelion (furthest distance). If an orbit disappears at any point, it is because of a close planetary encounter. We also don't talk about what happened to Mercury... I also made this video as an offshoot to my next video on Planetary Habitability - the Solar System's formation. CORRECTIONS: - I spelt "Rogue" wrong near the end of the video. My bad. - I have been seeing a few comments that are stating that the ending is not entirely clear about what happened to the 5th Giant, but that is the point. Because Planet Nine's existence is disputed, we cannot say for certain that the 5th Giant was ejected from the system. It likely was, but first we need to find Planet Nine, and then see if there is a correlation between it and the hypothesised 5th Giant that this simulation highlights to see if they are the same object. If Planet Nine doesn't exist, then we can say for certain that the 5th Giant was ejected in the Early Solar System. - Fixed the wrong use of "It's" in the video title. (17/07/22) Software: Universe Sandbox (NOTE: Universe Sandbox 1 is now known as "Universe Sandbox Legacy", while Universe Sandbox 2 is now just known as "Universe Sandbox") Steam workshop link to scenario: References/Sources: Nice Model Jumping-Jupiter Scenario Five-planet Nice model Late Heavy Bombardment Evidence for a Distant Giant Planet in the Solar System (Batygin and Brown, 2016) Planet Nine #Batygin_and_Brown_hypothesis Music: Spirit of Fire - Jesse Gallagher (April 2020)