Astronomers have been faced with a debate for a long time: are Saturn's rings a "pipiole" on the time scale of the Solar System or as old as the planet they surround?
Against the old age argument , there was a compelling thesis: if they really were billions of years old, the dust progressively deposited on them would have darkened them.
Now, the data sent by the NASA Cassini probe seems to dismantle this hypothesis . For the first time, the spacecraft (in the orbit of Saturn since 2004) has measured the pollution index, and experts have found that it is up to 40 times lower than expected.
Sascha Kempf of the University of Colorado and his colleagues have detected in seven years only 140 types of dust particles from the Solar System large enough to make a mess.
Experts believe that most of the particles would arrive from the Kuiper Belt , a remote region where Pluto and other icy bodies are found.
With this data in hand, the rings could be the same age as Saturn itself – about 4.4 billion years – and not "just" hundreds of millions, as many experts have held up to now.
