Saturn's rings are younger than the planet itself

WASHINGTON: Saturn'sringsareyoungerthan scientists thought and appeared within thelast 10 to 100 million years, according to research published Thursday based on findings from NASA's Cassini spacecraft.
The sixth planet from theSun formed about 4.5 billion years ago, along with the rest of the planets in our solar system, and spent the bulk of its existence without the characteristic rings it is known for today.
Astronomers have long believed therings could be young, and perhaps formed by collisions between the moons of Saturn or by a comet that shattered in close proximity to theplanet.
Some of these answers have come into sharper focus because of Cassini, an unmanned US-European probe that launched in 1997 and ended in 2017 with a planned death plunge into Saturn's surface.
At the end of its mission, Cassini made 22 orbits, circling between Saturn and its rings, getting closer to them than any spacecraft in history.
By studying how the flight path of Cassini was deflected by the gravity of therings, scientists were able to deduce therings' mass and approximate age.
"Only by getting so close to Saturn in Cassini's final orbits were we able to gather the measurements to make the new discoveries," said lead author Luciano Iess of Sapienza University of Rome.
Understanding therings' age and mass is "a fundamental goal of its mission," he added.
A lesser mass indicates youngerrings because as they age, therings would attract more debris and grow heavier.
Theringsare made up of 99 percent ice.
The study did not delve into the question of where therings came from, but supported theories such as a comet or moon collision.