Data returned by NASA’s Voyager 1 and 2 probes as they approached Saturn in 1980 and 1981 respectively led some planetary science experts to suspect that the gas giants appeared to be losing its characteristic rings. Well, a new study by the US space agency has not only confirmed that hypothesis, but has also made it possible to find out that these are fading at the speed estimated by the worst of the scenarios predicted by the researchers . In a statement, they indicate that they are being dragged by the planet’s gravity and the influence of its magnetic field, which causes a shower of ice particles, of which they are largely composed.
“Every half hour, this phenomenon draws from the ring system an amount of water equivalent to that contained in an Olympic swimming pool,” says James O’Donoghue of the Planetary Magnetosphere Laboratory at NASA’s Goddard Space Flight Center. According to O’Donoghue, who has coordinated the aforementioned work, recently published in the magazine Icarus , “if we only took this fact into account, we could affirm that in about 300 million years they will have completely disappeared; However, measurements made by the Cassini probe – it disintegrated in the upper layers of Saturn’s atmosphere on September 15, 2017 -, which determined that more material from the rings was falling on the planet’s equator, could significantly advance that moment. They probably have less than 100 million years left, relatively little time if we compare it with the age of Saturn, which exceeds 4,000 million years ”.
An ‘ephemeral’ composition
Precisely, astronomers have debated for decades whether it was already formed with its rings, a structure that is currently 275,000 km in diameter, or whether it acquired them over time – one of the most considered proposals considers that they arose when they collided with each other. some small icy bodies that were in orbit around the gas giant. The new essay bets on this last hypothesis and its authors point out that, likewise, it is very likely that they are not more than 100 million years old, the period that it would take for ring C, more tenuous than A and B, to acquire the aspect it presents today, at least if we assume that it was once as dense as the one that precedes it . “We are lucky; we can observe the ring system of this planet, which seems to be in the middle of its life. However, if, as we suspect, they are ephemeral, surely we have missed being able to contemplate such impressive formations as these on Jupiter, Uranus or Neptune, whose rings are currently much finer ”, adds O’Donoghue.
Image: NASA / JPL-Caltech
Reference: Observations of the chemical and thermal response of ‘ring rain’ on Saturn’s ionosphere . James O’Donoghue et al. Icarus (2018). DOI: doi.org/10.1016/j.icarus.2018.10.027
