Monday , June 14 2021

The spectacular rings of Saturn are "very young"

The final phases of the mission must yield new information about the interior of SaturnImage copyright
Image Team Cassini / SSI / JPL / ESA / NASA

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The final phases of the mission must yield new information about the interior of Saturn

We are looking at Saturn at a very special moment in the history of the Solar System, according to scientists.

They confirmed that the planet's iconic rings are very new – no more than 100 million years ago, when dinosaurs still walked the Earth.

The insight comes from the final measurements taken by the American probe Cassini.

The satellite sent back its latest data before plunging into the giant atmosphere of the world in 2017.

"Previous estimates of the Saturn-era rings required a lot of modeling and were much more uncertain, but now we have direct measures that allow us to narrow our age very well," said Luciano Iess of the Sapienza University in Rome, Italy. .

The professor's team published an account of their work with Cassini in the journal Science.

Cassini: A mission of "amazing discovery"

Cassini circulates around Saturn 13 years ago

On the icy moon Enceladus discovered …

an ocean of water hidden beneath the surface

eight times deeper than the oceans on Earth.

Chemical analysis of Cassini water

suggests that the conditions may be suitable for microorganisms living there.

When you visit Saturn's largest moon

which is the size of the planet Mercury

Cassini flew over seas and methane lakes

and found that they are up to 170 meters deep.

On Saturn itself, above the north pole

Cassini took photos of a 32,000-kilometer-diameter hexagonal hurricane.

Scientists have been intrigued about how this giant storm spins.

Cassini measured its winds at an impressive 330 mph

Four times stronger than a hurricane on Earth!

Back on the edge of one of Saturn's rings

between the clouds of ice particles

Cassini even captured the birth of a possible new moon.

It has been called Peggy and is only 1km wide.

Finally, running out of fuel,

Cassini flew directly to the planet

until it burned in Saturn's atmosphere.

There has long been a debate about the age of Saturn's rings. Some have argued that these beautiful loops of ice particles probably formed along with the planet itself, about 4.5 billion years ago.

Others suggested that they were a recent phenomenon – perhaps the crushed remains of a moon or a comet that was involved in a collision.

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Artwork: Cassini plunged between the rings and clouds of the planet

The US mission Cassini has promised to resolve the argument in its last months on the gas giant.

The final days of the satellite saw him fly repeatedly through the space between the rings and the clouds of the planet.

These maneuvers have made unprecedented measurements of gravity possible.

Cassini basically weighed the rings and found that its mass was 20 times smaller than the previous estimates: something of the order of 15,400,000,000,000,000 tons, or about two-fifths of the mass of Mimas – the moon of Saturn that looks like with the weapon of "Star of Death" the movies of Star Wars.

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Image Team Cassini / SSI / JPL / ESA / NASA

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Mimas: The "Star Wars" moon is a favorite among fans of Saturn

Knowing the mass was a key piece in the puzzle for the researchers.

Of the other Cassini instruments, they already knew the proportion of dust in the rings and the rate at which that dust was being added. Having a definite mass for the rings, then made it possible to work an age.

Prof. Iess's team says that this can be as young as 10 million years, but it is no more than 100 million years old. In terms of the complete age of the Solar System, this is "yesterday".

The calculation is in line with one made by a different group who last month examined how fast the ring particles were falling on Saturn – a rate that was described as equivalent to an Olympic pool every half hour.

This flow, when all factors were considered, would probably see the rings disappear in "at most 100 million years," said Tom Stallard of Leicester University in the United Kingdom.

"The rings we see today are not as impressive compared to what they look like 50 to 100 million years ago," he told BBC News.

"At that time, they would have been even bigger and brighter, so whatever produced them must have made an incredible display if you were an astronomer 100 million years ago."

Cassini's investigations may not shed much light on the nature of the event that gave rise to the rings, but would have been cataclysmic in scale.

It was conceivable, Dr. Stallard said, that the geology of the moons around Saturn might contain important clues. Just as rock and ice cores drilled on Earth reveal fragments of ancient meteorites and comet impacts, it is possible that Saturn's moons can record evidence of the ring-forming event in its deepest layers.

Maybe we can pierce the likes of Mimas and Enceladus … someday.

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