Scientists proposed a new theory of why Uranus “lies on its side”

Scientists have proposed a new explanation for why Uranus has an orbital inclination of 98 degrees. In their opinion, the migration of a large moon over millions of years could lead to this.

Uranus. Source:

Why does Uranium “lie on its side”?

Uranus is known for having an inclination of the plane of rotation to the ecliptic of 98 degrees. In practice, this means that it moves in its orbit as if rolling on its side and rotates in the opposite direction from all other large bodies of the Solar System.

Such a strange situation is usually explained by the collision of a planet with some large body. An alternative theory says that there were several meetings, but with much smaller objects. However, both of these statements are very difficult to verify.

So, scientists from a number of universities in France, Italy and the USA have proposed an alternative model, published in the journal Astronomy & Astrophysics. In their opinion, a large moon that changed its orbit for millions of years could “flip” the planet.

Uranus, Saturn and moons

Only recently, another group of scientists published a study according to which the migration of Saturn’s largest moon Titan, the precession of its axis and the large moon that existed more than 100 million years ago are connected into a single whole. 

With this in mind, the scientists decided to check whether a migration similar to the one that occurs with Titan could lead to the fact that Uranus is now “lying on its side.” The fact is that Saturn’s largest moon is larger than Mercury and it is not a problem for it to cause such global changes.

It turned out that in order for the axis of rotation of Uranus to tilt by 98 degrees, it is enough to migrate a moon with a mass only two times smaller than the Moon. But even here the researchers found a problem. The available moons of the planet are smaller than this value.

However, the same simulation showed a solution to this problem. If Uranus had such a moon at the beginning of its existence, and over millions of years it would change the inclination of its axis, then when the inclination reaches 80°. After that, the system proceeds to a chaotic movement. It ends with the collision of the moon with the planet, after which the tilt of its axis stabilizes at a certain point. This assumption fully explains the situation that is currently being observed.

According to

Follow us on Twitter to get the most interesting space news in time