Of all the planets in our solar system, Saturn’s personification is certainly the most imaginative thanks to its massive rings… But even today, there is no consensus among experts on their origin, or even their age.
Researchers who conducted a study whose results were published in the prestigious “Science” journal Thursday, say they have an answer to this difficult question.
And the study stated in its conclusions that about a hundred million years ago, an icy moon broke up after it came too close to Saturn, and then the remains of this were laid. orb itself gradually into orbit around it.
“Galileo discovered the rings of Saturn about four centuries ago, and they are among the most interesting things that can be observed through a small telescope in the solar system,” said lead author of the study Jack Wisdom.
It is also satisfactory to “find a plausible explanation for their formation,” this professor of planetary sciences at the Massachusetts Institute of Technology told AFP.
The planet Saturn, the sixth planet from the sun, was formed four and a half billion years ago, in the early days of the formation of the solar system.
But a few decades ago, scientists said, the rings of this planet appeared much later: only about 100 million years ago.
This hypothesis was reinforced by observations transmitted by the Cassini probe, which was launched in 1997 and retired in 2017.
However, “since no one has been able to establish a path to prove that these rings formed only 100 million years ago, some have questioned the validity of the logic” under which this dating was made, according to Jack Wisdom.
Thus, the researcher and his colleagues prepared a complex model that allows not only to explain its relatively recent appearance, but also to understand another property of this planet, which is its curvature.
In fact, Saturn’s axis of rotation is tilted at an angle of 26.7 degrees to the vertical (the so-called eccentricity of the planet). However, because Saturn is a gas giant, it would have been expected that the accretion process that led to its formation would have left it in a trajectory perpendicular to the plane of its orbit.
gravitational forces
Researchers who modeled the interior of the planet for their calculations proceeded from a recent discovery: Titan, the largest of Saturn’s moons (the planet has more than 80 moons), is gradually moving away from the planet … and relatively quickly.
According to their model, this motion gradually changed the rate at which Saturn’s axis of rotation made a complete rotation about the vertical, just as the axis of the game Bulbul forms an imaginary cone as it rotates.
This detail is important. About a billion years ago, this frequency was in sync with the frequency of Neptune’s orbit. This powerful mechanism caused Saturn to tilt up to 36 degrees.
But the researchers found that this synchronization between Saturn and Neptune is no longer accurate today. Why? This can only happen by a major event.
From this perspective, the researchers hypothesized the existence of a moon with a chaotic orbit, which gradually became excessively close to Saturn until the contradictory gravitational forces caused it to dislodge it.
“It was torn down into many pieces, and these same pieces are still scattered, and little by little the rings are formed,” even though most of them descend toward Saturn, explains Jack Wisdom.
The influence of Titan, which continued to move away, eventually diminished the tilt of Saturn into what we see today.
Coming out of the cocoon
Jack Wisdom named the lost moon “chrysalis”, which is similar to the wings of butterflies emerging from a cocoon, as is the case in the formation of rings.
Scientists believe that Chrysalis was slightly smaller than Earth’s moon, and about the same size as another moon of Saturn, Iapetus.
However, the latter consists almost entirely of ice water.
“It is therefore reasonable to assume that the cocoon is also made of ice water, and this leads to the formation of rings” of which 99% are made, according to the professor.
When asked if he considers this study to have solved the mystery of Saturn’s rings, Wisdom answers, “We’ve made a good contribution,” but Saturn’s system and its moons still hide “a lot of mysteries.”