(ORDO NEWS) — The current orbits of the planets in the solar system seem stable, but that’s only because the planets settled in them over billions of years.
The early solar system was vastly different from today’s, and for nearly 20 years, scientists believed they had a good understanding of how it became that way.
But more recently, evidence has begun to point to some flaws in that understanding – especially how the giant planets in the outer solar system ended up where they are today.
Now an international team of astrophysicists believe they have a better understanding of this process, and they believe it could help resolve the longstanding dispute about the early solar system.
Currently, the best model of the formation of the solar system that scientists have is known as the Nice model, after the city in France where it was first developed in 2005.
According to this model, the gas giants currently at the outer edges of the solar system originally revolved around the Sun in more circular orbits.
However, something caused an instability in the system that pushed these planets into the much more unevenly spaced and oblong orbits we see them in today.
What exactly caused this anomaly is still a mystery. However, a team of researchers from Michigan State University, Zhejiang University and the University of Bordeaux think they have the answer. It’s simple – it’s dust in the (solar) wind.
In the early solar system, gas giants were located in a dusty cloud around the nascent sun in almost circular orbits.
When the Sun flared up, it began to blow off the dust in the circumstellar disk. Some of this dust accidentally flew past the orbit of the gas giants, causing the instability seen in the Nice model.
However, the way the researchers developed this idea also solves some of the problems that the Nice model had. One of the main problems was that the data collected from the moon samples indicated a much faster path to this instability, which was usually seen in the original Nice model.
In the updated model of evaporation of a dust cloud “from the inside out”, the laborious path of this instability of hundreds of millions of years is reduced to several million years, which agrees much better with the available data.
However, this is not the only data with which it agrees well. The Nice model itself is kind of controversial as it points to a potential ninth planet in the early solar system – and that doesn’t mean Pluto.
Beloved by many conspiracy theorists, Planet 9 (or Planet X) is gaining more and more attention after a 2015 Caltech study showed that something huge could be lurking 50 billion miles from the Sun.
The original Nice model actually works better with five inner gas giant planets, but in these calculations, one of these planets is ejected into interstellar space and becomes a rogue planet.
In the updated model, the result of planetary orbit alignment is essentially the same whether there are four or five initial gas giants in the system. However, they correspond slightly better to reality if only four planets are initially introduced into the model.
Like many other theories, this new model has the potential to change our understanding of the formation of the early solar system and resolve the longstanding debate about what was the initial impetus for the instability that shaped our planetary neighbors.
But ultimately, even this new model must match the data, and there is still a lot of data to collect before the true history of our early solar system becomes clear.
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