ǿմý

Skip to main content

New theory suggests Saturn once had another moon, which knocked it out of resonance with Neptune

This Oct. 6, 2004 photo provided by NASA, taken by the Cassini Saturn Probe, shows the planet Saturn and its rings. (AP Photo / NASA) This Oct. 6, 2004 photo provided by NASA, taken by the Cassini Saturn Probe, shows the planet Saturn and its rings. (AP Photo / NASA)
Share

An ancient moon which was torn apart after it spun too close to Saturn may be the cause of the planet’s tilted rings, according to new research.

Saturn’s lean has always been clear through its rings, which spin around the planet at a 26.7-degree angle compared to the planet’s orbit around the Sun.

While this was long thought to be connected to the gravitational force of Saturn’s neighbour, Neptune, due to how closely the spin of Saturn aligns with the pattern of Neptune’s orbit, astronomers now believe that connection between the two planets has since been broken.

But if Saturn isn’t tilting to pull toward Neptune, what is the reason behind its current tilt? And could it be connected to the relatively recent formation of Saturn’s rings, which have previously been estimated to be only 100 million years old?

Astronomers believe they have found an explanation that could answer a number of these unexplained Saturn anomalies: an extra moon which died so the rings could form.

In a new study published Thursday in the journal Science, authors have dubbed this moon “Chrysalis.”

If Chrysalis existed as moon number 84, it would’ve assisted in keeping Saturn in line with Neptune for several billion years, the study suggests.

Then, around 160 million years ago, according to researchers’ computer modelling, Chrysalis’s orbit became unstable and it grazed the planet itself — a catastrophic event which would’ve pulled the moon apart, and would also explain how Saturn was pulled from its pattern with Neptune to acquire its current tilt.

The shattered pieces of Chrysalis which didn’t fall to Saturn were then flung into orbit around it, eventually crumbling into smaller icy pieces to make up the planet’s rings.

“Just like a butterfly’s chrysalis, this satellite was long dormant and suddenly became active, and the rings emerged,” Jack Wisdom, professor of planetary sciences at Massachusetts Institute of Technology and lead author of the new study,

This theory patches a number of holes in previous explanations for Saturn’s orbit, rings and tilt, researchers say.

It was first suggested in the 2000s that Neptune and Saturn were bound in a gravitational association, but when NASA’s Cassini flew out to visit the planet from 2004 to 2017, its observations brought new complications.

Cassini’s observations of Titan, Saturn’s largest moon, led to the theory that this large moon was actually responsible for Saturn’s tilt, forcing it into alignment with Neptune. However, this only made sense if the gas giant’s mass was distributed in a particular way — since the planet’s composition makes it difficult for us to tell if its mass is concentrated more towards the core or not, the planet’s moment of inertia is hard to pinpoint.

Wisdom and his colleagues set out to see if Cassini’s final observations — gathered in the last moments of its existence as the spacecraft plunged towards the surface of Saturn — could shed light on the issue.

These final observations made it possible to create a gravitational field of Saturn that allowed researchers to model the way mass is distributed across the planet.

They found that the moment of inertia they’d been searching for meant that Saturn was actually slightly out of alignment with Neptune. The planets were no longer in sync.

“Then we went hunting for ways of getting Saturn out of Neptune’s resonance,” Wisdom said.

After modelling numerous scenarios, the team discovered that the math balanced out if a new moon was added and then subtracted in a cataclysmic event.

They theorize that Chrysalis’ orbit became chaotic between 100-200 million years ago, and that after it had some near misses with some of the other large moons such as Titan, it grazed by Saturn itself, travelling too close to survive the encounter.

Chyrsalis would’ve had to be about the size of Iapetus, Saturn’s third-largest moon, to explain how its destruction and loss could’ve pulled Saturn out of resonance with Neptune.

“It’s a pretty good story, but like any other result, it will have to be examined by others,” Wisdom says. “But it seems that this lost satellite was just a chrysalis, waiting to have its instability.” 

CTVNews.ca ǿմý

The province's public security minister said he was "shocked" Thursday amid reports that a body believed to be that of a 14-year-old boy was found this week near a Hells Angels hideout near Quebec City.

Since she was a young girl growing up in Vancouver, Ginny Lam says her mom Yat Hei Law made it very clear she favoured her son William, because he was her male heir.

An Ontario man says it is 'unfair' to pay a $1,500 insurance surcharge because his four-year-old SUV is at a higher risk of being stolen.

For the last seven-and-half months, Toronto resident Heather McArthur has been living out what she describes as her 'worst nightmare.' On Feb. 7, her then three-year-old son Jacob along with his father Loc Phu 'Jay' Le departed for what was supposed to be a week-long visit to Vietnam to celebrate the Lunar New Year with family, McArthur says.

Local Spotlight

They say a dog is a man’s best friend. In the case of Darren Cropper, from Bonfield, Ont., his three-year-old Siberian husky and golden retriever mix named Bear literally saved his life.

Paleontologists from the Royal B.C. Museum have uncovered "a trove of extraordinary fossils" high in the mountains of northern B.C., the museum announced Thursday.

The search for a missing ancient 28-year-old chocolate donkey ended with a tragic discovery Wednesday.

The Royal Canadian Mounted Police is celebrating an important milestone in the organization's history: 50 years since the first women joined the force.

It's been a whirlwind of joyful events for a northern Ontario couple who just welcomed a baby into their family and won the $70 million Lotto Max jackpot last month.

A Good Samaritan in New Brunswick has replaced a man's stolen bottle cart so he can continue to collect cans and bottles in his Moncton neighbourhood.

David Krumholtz, known for roles like Bernard the Elf in The Santa Clause and physicist Isidor Rabi in Oppenheimer, has spent the latter part of his summer filming horror flick Altar in Winnipeg. He says Winnipeg is the most movie-savvy town he's ever been in.

Edmontonians can count themselves lucky to ever see one tiger salamander, let alone the thousands one local woman says recently descended on her childhood home.

A daytrip to the backcountry turned into a frightening experience for a Vancouver couple this weekend.