Uranium is one of the most unusual planets in the solar system. Its axis is tilted at an angle of 98 degrees to the plane of the ecliptics. This means that the planet is actually lying on its side. In addition, unlike all other planets in our system, it rotates clockwise. Scientists have found a plausible explanation for this strange behavior.
Researchers have modelled with a number of parameters, including the mass of a hypothetical satellite, and they have discovered that an object with a minimum mass of about half the mass of the Earth's moon can tilt Uranus by 90 degrees if it migrates more than 10 times the planet's radius at a rate of more than 6 cm per year.
Although the planet currently does not have the right size satellite, and even the mass of all available moons is insufficient, researchers believe that at an inclination of about 80°, the satellite destabilized, causing chaotic changes in the axis of rotation; after the impact of the satellite with Uranus, the orbit was recorded in the current position.
It's not unusual for the moons to migrate, to be explained by scientists. The Earth's moon, for example, moves away from Earth at a rate of about four centimetres a year. Bodies orbiting around a common centre of gravity affect each other by a tide force that slowly slows their rotation. In turn, it weakens gravity, so the distance between the two bodies increases.
If the results of the proposed theory are confirmed, one mystery in the life of the planet will be less.