The “Nice Model” is a series of studies published in 2005 that explain the formation of our Solar System. Today, it is the model that achieves consensus among the scientific community. This model was especially successful in explaining why the gas giant planets (Jupiter, Saturn, Uranus, and Neptune) ended up in oblong and widespread orbits. These studies suggest that during the formation of our solar system, there was a ” instability chaotic between the planets, that is, a collision of gravitational forces that has led to the current placement of the giant planets.
However, the Nice model works best when we conceive of the existence of a fifth gaseous planet in our Solar System. However, instability would have expelled him according to this model.
Beautiful model: an almost perfect model?
The analysis of the lunar rocks extracted by the Apollo mission, as well as other phenomena of the Solar System, created theoretical tensions on this model that remained to be deepened. In particular, a discrepancy in the timeline, because the analysis of lunar rocks has led to the conclusion that the primordial gas, which gave rise to the planets, dispersed hundreds of millions of years earlier than previously thought. It is these tensions that are at the root of this new study.
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A new theory about the formation of planetary systems
A new study, published in the journal Nature describes the phenomenon that would be at the origin of “planetary instability” and therefore of the position of the planets in current orbits. To do this, the researchers who participated in this study took a look at the formation of planetary systems, including the Solar System. ” We wondered if the Nice model was really necessary to explain the solar system. We hypothesized that giant planets could eventually propagate through a “bounce” effect as the disk dissipates, perhaps without ever becoming unstable. “ announced Sean Raymond, a CNRS researcher at the University of Bordeaux and co-author of the study, in a press release.
The international team of scientists joined forces to find an answer to this question: what would be the trigger for the instability of the planets? So they designed a model where the gas disk – which gave birth to the planets – would have dissipated from the inside to the outside. ” All solar systems form a disk of gas and dust. It is a natural byproduct of star formation explains Seth Jacobson of Michigan State University and co-author of the study. ” But when the sun ignites and begins to burn its nuclear fuel, it generates sunlight, heating the disk and finally blowing it from the inside out. “continues in press release.
This study also offers an explanation of the formation of planetary systems and not just ours. “What we are showing is that the instability came in a different, more universal and more consistent way.” says researcher Seth Jacobson. ” We ended up strengthening the Nice model rather than destroying it adds co-author Sean Raymond.
Did Planet X really exist?
In 2015, Caltech astronomers rekindled the debate over the number of planets when they found new evidence that the ninth planet could be lurking 47 billion kilometers from the Sun.
The authors of the new study performed simulations on their new model considering eight, and then nine planets at the origin of the Solar System. Of the two possibilities, the end result represents the Solar System as we conceive it today, with a slight subtlety. ” If you start with five gaseous planets, you are more likely to end up with four. But if you start with four gaseous planets, the orbits will eventually match the actual system better. explains researcher Seth Jacobson.
This animation shows the results of a simulation that illustrates how the solar system could have been rearranged by a cloud of dust and evaporating gas. The inner edge of this cloud, represented by a vertical gray line, begins near the sun (far left) and crosses the orbits of Jupiter, Saturn, a hypothetical fifth gas giant, Uranus, and Neptune. Credit: Liu et al.
However, the riddle will not go unresolved for a long time. The Vera Rubin Observatory, which is due to see the light of day in 2023, will be able to observe the confines of our solar system to confirm whether a planet X really existed.
Originally published on 02/05/2022