Strange orbits in outer solar system are not shaped by 'planet nine' reveals new study
New Delhi : A recent space research claims that the mystery orbits of unknown in the outermost reaches of our solar system are not caused by the hypothesised ‘Planet Nine'. The phenomenon can be explained by the gravitational force of small bodies orbiting the Sun beyond Neptune.
The detailed explanation to the ‘Planet Nine’ hypothesis has been given by researchers at the University of Cambridge in the UK. They say it is a disc made up of small icy bodies with a combined mass as much as ten times that of Earth.
When researchers combined with a solved model of the solar system, the gravitational forces of the hypothesised disc can account for the unusual orbital architecture exhibited by some objects at the outer reaches of the solar system. The study has been published in the Astronomical Journal.
However, the new theory is not the only one to propose that the gravitational forces of a massive disc made of small objects could avoid the need for a ninth planet. In fact, it is the first such theory which is able to explain the significant features of the observed orbits while accounting for the mass and gravity of the other eight planets in our solar system.
Astronomers say that beyond the orbit of Neptune, there lies the Kuiper Belt, which is made up of small bodies left over from the formation of the solar system. Neptune and the other giant planets gravitationally influence the objects in the Kuiper Belt and beyond, collectively known as trans-Neptunian Objects (TNOs), which revolves around the Sun on somewhat circular paths from almost all directions.
Since 2003, around 30 TNOs on highly elliptical orbits have been spotted which stand out from the rest of the TNOs by sharing, on average, the same spatial orientation.
Such a clustering cannot be explained by the existing eight-planet solar system architecture and has led to some astronomers hypothesising that the unusual orbits could be influenced by the existence of an unknown ninth planet.
The ‘Planet Nine’ hypothesis suggests that to account for the unusual orbits of these TNOs, there would have to be another planet, believed to be about ten times more massive than Earth, lurking in the distant reaches of the solar system and ‘shepherding’ the TNOs in the same direction through the combined effect of its gravity and that of the rest of the solar system.
“The Planet Nine hypothesis is a fascinating one, but if the hypothesised ninth planet exists, it has so far avoided detection,” said Antranik Sefilian, a PhD student at Cambridge University.
“We wanted to see whether there could be another, less dramatic and perhaps more natural, cause for the unusual orbits we see in some TNOs.
“We thought, rather than allowing for a ninth planet, and then worry about its formation and unusual orbit, why not simply account for the gravity of small objects constituting a disc beyond the orbit of Neptune and see what it does for us?” Sefilian said.
Professor Jihad Touma, from the American University of Beirut, and Sefilian modelled the full spatial dynamics of TNOs with the combined action of the giant outer planets and a massive, extended disc beyond Neptune.
The calculations revealed that such a model can explain the perplexing spatially clustered orbits of some TNOs.
“We thought, rather than allowing for a ninth planet, and then worry about its formation and unusual orbit, why not simply account for the gravity of small objects constituting a disc beyond the orbit of Neptune and see what it does for us?” Sefilian said.
Professor Jihad Touma, from the American University of Beirut, and Sefilian modelled the full spatial dynamics of TNOs with the combined action of the giant outer planets and a massive, extended disc beyond Neptune.
The duo’s calculations revealed that such a model can explain the perplexing spatially clustered orbits of some TNOs.
Scientists were able to identify ranges in the disc’s mass, its roundness and forced gradual shifts in its orientations which faithfully reproduced the outlier TNO orbits.
