A new work led by Matt Clement of Carnegie reveals the likely original positions of Saturn and Jupiter. These discoveries refine our understanding of the forces that determined the unusual architecture of our solar system, including the ejection of an extra planet between Saturn and Uranus, ensuring that only small, rocky planets such as Earth were formed inside Jupiter.
In our youth, our sun was surrounded by a swirling disk of gas and dust from which planets were born. The orbits of the early-formed planets were thought to be initially tightly packed and circular, but the gravitational interactions between larger objects disrupted this system and caused the small giant planets to quickly shuffle into the configuration we see today.
“We now know that there are thousands of planetary systems in our Milky Way galaxy alone,” said Clement. “But it turns out that the system of planets in our solar system is very unusual, so we use models to reverse engineering and duplicate formation processes. It’s a bit like trying to find out what happened in a car crash after the fact – how fast the cars were going, in what directions and so on. “
Clement and his co-authors – John Chambers of Carnegie, Sean Raymond of the University of Bordeaux, Nathan Kaib of the University of Oklahoma, Rogerio Deienno of the Southwest Research Institute, and André Izidoro of Rice University – conducted 6,000 simulations of our solar system evolution, revealing unexpected details of the original the relationship of Jupiter and Saturn.
Jupiter was believed to have orbited the Sun three times in his childhood for every two orbits completed by Saturn. But this system cannot satisfactorily explain the configurations of the giant planets we see today. The team’s models showed that the ratio of Jupiter’s two orbits to one of Saturn’s more consistently produced results that look like our familiar planetary architecture.
“This indicates that although our solar system is a bit bizarre, it has not always been so,” explained Clement, who today presents the team’s work at a virtual meeting of the Planetary Sciences Division of the American Astronomical Society. “Moreover, now that we have established the effectiveness of this model, we can use it to help us look at the formation of the terrestrial planets, including our own, and perhaps to inform us of the possibility of searching for similar systems elsewhere that might have potential to take life. “
The model also showed that the positions of Uranus and Neptune were shaped by the mass of the Kuiper belt – an icy region at the edges of the solar system made up of dwarf planets and asteroids of which Pluto is the largest member – and by an ice giant planet that was ejected in the solar system’s infancy.
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