Uranus marches to the rhythm of its strange little drum.
Although it bears many similarities to another ice giant in our solar system, Neptune, it is one of a kind.
And one of those things is impossible to miss: its axis of rotation is so inclined that it could even lie down. This is a large inclination of 98 degrees from the plane of the orbit.
Most importantly, it rotates clockwise, the opposite direction to most other planets in the solar system.
A new study has found a plausible explanation for this strange behavior: the moon is migrating away from the planet, dragging Uranus aside. And it doesn’t even have to be a big month. Something half the mass of our moon could do so, although a larger moon would be the most likely contender.
The reason is explained in a research paper led by astronomer Mylene Silinvest of the National Center for Scientific Research in France. This article, which has not yet been peer-reviewed, has been accepted in the journal Astronomy and astrophysics and available in pre-printed resources arXiv.
Scientists have found patterns to explain this strange behavior, such as a large object colliding with Uranus and she really slapped him in the facebut my favorite Explanation he is Packaging From smaller things.
However, this hypothesis poses a difficult problem to explain: a disturbing resemblance to Neptune.
The two planets have very similar masses, rays, rotational speeds, atmospheric dynamics and composition, as well as strange magnetic fields. These similarities suggest that the two planets can be born together and reconciling them becomes even more difficult when incorporating the planetary core effect into the mix.
This has led scientists to look for other explanations, such as the fluctuations it could provide Giant ring system or giant moon Early in the history of the solar system (albeit with a different mechanism).
But then, a few years ago, Saillenfest and company found something interesting Jupiter. Thanks to the moon, the gas giant’s tilt could increase from the current 3% a About 37 percent in a few billion yearsThanks to migration beyond the moon.
Then they looked at Saturn and found that its current tilt of 26.7 degrees could be the result of Fast external migration from its largest moonAnd Titan. They found that this could happen almost without affecting the planet’s rotational speed.
This clearly raises the question of the most tilted planet in the solar system. Then the team ran simulations of a hypothetical Uranus system to determine if a similar mechanism could explain its strangeness.
It is not uncommon for the moon to migrate. Our moon is currently moving away from Earth at a rate of 4 centimeters (1.6 inches) per year. Objects that rotate back and forth around a center of gravity exert tidal forces on each other which gradually slows down their rotation. This, in turn, loosens the grip of gravity so that the space between the two objects expands.
Back on Uranus, the team ran simulations using various parameters, including the mass of a hypothetical moon. They found that a moon with a mass of at least half the mass of Earth’s moon could tilt Uranus by about 90 degrees if it migrated more than 10 times the radius of Uranus at a rate of more than 6 centimeters per year.
However, a larger moon, similar in size to Ganymede, was more likely, in simulations, to produce the tilt and spin we see on Uranus today. However, the minimum mass – about half that of Earth’s moons – is about four times the combined mass of the currently known moons of Uranus.
This work also explains this point. with an inclination of about 80 degrees, moon It became unstable, causing a chaotic phase of its axis of rotation that ended when the Moon finally collided with the planet, “petrifying” the tilt and axial rotation of Uranus.
“This new image of the inclination of Uranus looks very promising to us”, write researcher.
“As far as we know, this is the first time that a mechanism has been able to tilt Uranus and swing its axis of rotation to its terminal state without causing a gigantic jolt or other external phenomena. The most successful run ended in the position of Uranus, which appeared as a result of the dynamic “hmm Keep on.
“This image also seems interesting as a general phenomenon: Jupiter will begin its tilt phase today, Saturn may be in the middle and Uranus has completed its final phase, with its satellite destroyed.”
It is unclear whether Uranus hosts a moon large enough and with a sufficiently high migration rate to produce this scenario, the researchers say, it would be difficult to prove through observation.
However, a better understanding of the current migration rate of Uranus’ moons would be helpful in answering these questions. If they migrated at high speed, it could mean that they formed from the debris of the ancient moon after being destroyed several eons ago.
Bring Investigation of that Uranus.
The research was accepted Astronomy and astrophysics and available to arXiv.
