Uranus march to the beat its own strange little drum.
While it shares some similarities with Neptune (the other ice giant of the Solar System), it has its own unique set of quirks.
This is the most obvious: The orbital plane’s rotational axis may be so disoriented it might as well be lying on its side. This tilt is 98 degrees away from the orbital plan.
And, to top it all off, it’s rotating clockwise – the opposite direction from most of the other planets in the Solar System.
New research has provided a plausible explanation: Uranus was pulled onto its side by a moon that had been moving away from the planet. It wouldn’t have to be large. A moon half the mass as our Moon could have done it. However, a larger moon is more likely to succeed.
This reasoning has been presented in a paper written by Melaine Saillenfest (National Centre for Scientific Research in France). This paper has been accepted by the journal, although it is still not peer-reviewed. Astronomy & AstrophysicsAvailable on preprint resource arXiv.
Scientists have created models to explain this bizarre behavior, such a colliding object with Uranus. Literally, I smacked it upside downHowever, the most favored is Please explainIt is possible to BunchOf smaller objects.
This hypothesis however raises questions that are harder to explain, such as the pesky similarities to Neptune.
They have very similar masses, radii and rotation rates. They also share the same atmosphere dynamics and compositions. These similarities indicate that they could have been created together. It becomes more difficult to reconcile them when planet-tipping impacts are added.
Scientists have looked for other explanations. For example, a wobble could have been caused by an accident. System of giant ringsOr a The giant moonEarly in the history of the Solar System (albeit with a different mechanism).
Saillenfest, along with his colleagues, discovered something that was quite interesting about Saillenfest’s work a few decades ago. Jupiter. The gas giant’s tilt could be increased from the current 3 percent by its moons. In a few billion years, around 37 percentIt is possible because of the outward movement of its moons.
They took a closer look at Saturn to determine if its current tilt of 26.7° could be the result. Rapid outward migration by its largest moon, Titan. This could have happened, they discovered, almost without any effect upon the planet’s spinning rate.
This raised concerns about the tiltedest planet in the Solar System. The team then created simulations of hypothetical Uranian systems to see if similar mechanisms could explain its unique features.
Moons can migrate quite often. Our Moon is moving away from Earth at an average rate of 4 cm (1.6 inches) per calendar year. A mutual center of gravity is a body orbiting another that exerts a tidal effect on one another, slowing down their rotations. This causes gravity to loosen and the distance between them increases.
They then looked back at Uranus and ran simulations with various parameters. The team also considered the mass of the hypothetical Moon. The team found that a moon that had a minimum mass equal to that of Earth’s Moon could tilt Uranus towards the 90-degree angle if it moved by more than 10x the radius of Uranus at a rate of greater than 6 cm per year.
In simulations however, it was more likely that a larger moon of comparable size to Ganymede would produce the tilt and spin seen in Uranus today. However, the minimum mass – about half an Earth Moon – is about four times the combined mass of the current known Uranian moons.
This is also due to the work. A tilt of approximately 80 degrees. The moonDestabilization caused a phase of chaos for the spin-axis, which ended when the moon collided with the planet. This effectively “fossilized Uranus’ spin and axial tilt.
“This new picture of the tilting Uranus seems quite promising to me.” Write to the researchers.
“This is the first attempt to tilt Uranus in a single mechanism without requiring a large impact or any other external phenomena. They found that the majority of our runs were successful at Uranus’s site, which is a natural result of the dynamics.” Continue.
“This picture is also appealing as a generic phenomenon: Jupiter today may be about to enter the tilting stage, Saturn may already be halfway in, Uranus would have completed its final stage, with destruction of its satellite.”
It isn’t clear if Uranus could have held a moon large enough or at a high migration rate to produce such a scenario. Researchers say it will be challenging to demonstrate with observations.
A better understanding of the current rate at which Uranus’s moons migrate would help to resolve these issues. It could be that they have formed from the remains of an old moon after its destruction thousands of years ago.
Bring it on Uranus probe.
The research was accepted by the university. Astronomy & AstrophysicsIt is also available online arXiv.
