Uranus’ high tilt may be the result of a missing moon

Scientists have proposed a new scenario as the reason for the high tilt of Uranus' rotation axis, which can explain this phenomenon from various aspects.

BingMag.com Uranus’ high tilt may be the result of a missing moon

Scientists have proposed a new scenario as the reason for the high tilt of Uranus' rotation axis, which can explain this phenomenon from various aspects.

"Uranus" is a very strange planet, and one of its strangest features is the complete tilt of its rotation axis. With a 98 degree rotation axis deviation, this planet has the highest tilt in the solar system and rotates around itself almost perpendicular to its orbit around the sun. Uranus is causing it to spin sideways, but new research suggests a different reason: a moon that has moved away from Uranus. The direction of its rotation is tilted, and it has affected not only the rotation of the planet, but also its rings and moons, and the whole set perpendicular to the plane of Uranus' movement around the Sun, rotates around the planet. It is very strange that its neighboring ice giant Neptune has a normal slope and of course a similar formation date. Astronomers have long suspected that at least one large collision occurred during the formation of Uranus and caused this deviation. And it produced the rotation of the planet and the planet did not return to the top before the formation of its system of planets and moons.

Scientists have evidence to support this view. The Solar System was a pretty rough and bumpy place in its youth, so there were plenty of large space rocks around to collide with major bodies like the planets.

Neptune, by contrast, has a few differences, including a different temperature. And it has a set of moons with different characteristics and it is a little bigger. These cases show that the two planets experienced different conditions somewhere in their formation process.

The unluckiest planet

The collision hypothesis also has weaknesses. In the early days of the solar system, there wasn't just one big space rock looking for an unlucky target, but many stray objects.

BingMag.com Uranus’ high tilt may be the result of a missing moon

Voyager 2's view of Uranus
Credit: NASA/JPL

All planets, especially the outer planets, are probably They have had many collisions during their formation. Even the inner planets were not spared from this issue. Early in its life, the Earth collided with a Mars-sized protoplanet and formed the Moon.

  • The Moon may have formed instantaneously after a massive impact.

But if Uranus was tilted so much due to this impact, why didn't this happen to other planets? It can be said that Jupiter and Saturn eventually returned to their previous state due to the creation of thick gas clouds and with the passage of time.

But Neptune has a similar history to Uranus and these two ice giants are very similar despite the slight differences. They are: they have similar atmospheres, both have entangled magnetic fields, and have similar sizes, masses, and rotation rates. So why does Neptune not have such a slope?

So scientists are left in a dilemma. Uranus may have been extremely unlucky, and some simulations support the idea of a collision. But luck alone is not a convincing answer for astronomers and they must consider all other possibilities.

So maybe the tilting of Uranus has nothing to do with a collision and as a team of scientists in the paper accepted for The publication "Astronomy and Astrophysics" (Astronomy and Astrophysics) has stated that it is related to the moons of the planet.

Lost child

The solar system in its early days was not very similar to the structure of today. In particular, the giant planets probably formed much closer to each other and much closer to the Sun, but with the passage of time, the interaction between them caused them to move away from each other, and Uranus and Neptune were placed at the farthest points. In fact, some models of the solar system even predict the existence of a fifth massive planet that was ejected completely during this migration.

Each of the giant planets formed with a set of moons, but with The migration of the planets also changed the arrangement of these moons and due to the complex gravitational dynamics that was going on, some planets lost moons and new moons were added to others. So Uranus may have been born with or possessed by a giant moon. A moon that, if large enough, could even change the way the planet rotates.

According to this view, Uranus' rotation probably began with a random but small tilt. But over time, this slope in the direction of the planet's rotation, which is like a giant wobble eats, increased.

BingMag.com Uranus’ high tilt may be the result of a missing moon

Possible rotation process Axis of Uranus
Credit: MIT

On the other hand, although usually the rotation of a moon does not need to exactly match the degree of tilt of the mother planet, it may be locked in a resonance pattern with the planet. Take control of the order of increasing the inclination of the axis of the planet. As a result, the moon's gravity slowly pulls the planet and tilts it further.

Like an invisible string attached to the top of the planet, over millions of years, the tilt gets steeper and steeper. As this process continues, the moon's orbit gets closer to the planet. If this moon of Uranus was large enough, within a few hundred million years, it could change the tilt of the planet by more than 80 degrees. Finally, this moon will hit Uranus and lock the planet's tilt in its current position.

  • Uranus will be the next target of human exploration?

This scenario It explains why Uranus is so unique. The planet only had one large enough moon (which is common) and then got into resonance with the planet's tilting process (which is not so common for Neptune) and after hitting Uranus, it It is far away.

Cover photo: Uranus's ring and its rings
Credit: Keck/Nasa

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