Research

Saturn's halo may be relatively recent

Saturn's halo may be relatively recent

They suggested Saturn's massive gravity may have captured an icy object from the Kuiper belt or a comet and then broke down the object into debris, forming rings. Their age was determined by studying doppler-shifted radio signals from the doomed Cassini spacecraft. Cassini had observed clouds and rain in the southern hemisphere of Saturn's largest satellite when it first arrived at Titan in 2004. The gas giant Saturn, on the other hand, is 4.5 billion years old, like all the other planets in our solar system. Coauthor Mark Marley, now at NASA's Ames Research Center in Silicon Valley, subsequently fleshed out the idea for his Ph.D. thesis in 1990, showed how the calculations could be done, and predicted where features in Saturn's rings would be.

They've confirmed the planet's iconic rings are very young - no more than 100 million years old, when dinosaurs still walked the Earth.

Grand Finale was the official name of the Cassini spacecraft's last act: a risky orbit between the rings and the planet's atmosphere in a daring attempt to probe the planet from up close, right before the craft went up in flames.

Scientists often rely on magnetic fields to measure planets' rotation rates. Researchers were able to determine that the inner layers of Saturn's thick gaseous atmosphere rotate more slowly than the outer layers.

Scientists had previously relied on density waves, or ripples, through the rings caused by the motion of the 62 moons in Saturn orbit to estimate ring mass.

"We predict that there is a massive jet near the equator that rotates 4% faster than the rest of the planet", says team member Burkhard Militzer, of the University of California, Berkeley.

Saturn's rings boast a mass equivalent to 40 percent of the mass of Saturn's moon Mimas, which is 2,000 times smaller than Earth's moon. The two forces pull the spacecraft in opposite directions. According to the new data, the core features a mass of roughly 15 to 18 Earth masses.

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The length of a day on each of our solar system's planets ranges from a mere 10 hours on Jupiter, all the way up to 5,832 hours on Venus.

Such discoveries have strengthened the position of the supporters of the theory of "young rings" and forced planetary scientists to think about when they appeared.

The fact that the rings of Saturn and other giant planets should gradually fade due to the fact that on the surface of their grains of ice must be deposited tiny particles of dust and organic matter, gradually darkening as a result of its "bombing" of the ultraviolet rays of the Sun.

"The researchers used waves in the rings to peer into Saturn's interior, and out popped this long-sought, fundamental characteristic of the planet".

"Particles in the rings feel this oscillation in the gravitational field".

By estimating the mass of the rings through gravity measurements, the researchers gauged the age. One scientist who has studied the planet's magnetic field said that the day-length uncertainty is "a bit embarrassing", speaking in an interview with Space.com about research published in October.

Now we know there was a time when Saturn existed without its rings but we still don't know their exact age or how they were formed.