Saturn’s gravitational pull tore apart an ancient moon, creating its iconic rings and unusual tilt, new research suggests

Saturn’s gravitational pull tore apart an ancient moon, creating its iconic rings and unusual tilt, new research suggests

Scientists suggest a lost moon of Saturn, which they call Chrysalis, is pulled on the planet until it breaks apart, forming rings and contributing to Saturn's tilt.

Scientists suggest an ancient moon of Saturn, which they call Chrysalis, pulled the planet apart, forming rings and contributing to Saturn’s tilt.NASA/JPL-Caltech/Space Science Institute/G. Ugarkovic

  • New models suggest that Saturn’s gravity tore apart a moon, Chrysalis, about 160 million years ago.

  • The ancient moon could explain two long-standing mysteries: Saturn’s iconic rings and dramatic tilt.

  • Researchers believe that Chrysalis was probably the size of Iapetus, Saturn’s third largest moon.

Scientists say a single moon could clear up two cosmic mysteries about Saturn.

When Galileo Galilei first looked at Saturn in 1610, the astronomer noticed that the planet had what appeared to be “ears.” They turned out to be Saturn’s iconic rings. How and when these rings formed have puzzled astronomers ever since.

Another mystery of Saturn is its dramatic tilt of 27 degrees to one side. According to the researchers, this gradient is too large to have formed when the gas giant did, or to have been the result of collisions that knocked the planet apart. In comparison, Earth’s tilt oscillates between 22.1 and 24.5 degrees.

In a study published Thursday in the journal Science, researchers ran a series of simulations that suggest Saturn’s rings and unusual tilt may have formed 160 million years ago, when one of its icy moons destabilized and fell into a chaotic orbit around the planet. Eventually the moon – which the researchers named Chrysalis – got too close to the gas giant and broke up.

The models are based on data from the final stage of NASA’s Cassini mission, which spent 13 years orbiting Saturn and its moons before plunging into the planet’s atmosphere in 2017.

On July 29, 2011, Cassini captured five of Saturn's moons in a single frame.

Cassini captured five of Saturn’s moons in a single frame on July 29, 2011.NASA/JPL-Caltech/Space Science Institute

Today, the giant’s planetary system is home to 83 moons. Researchers believe that Chrysalis was probably the size of Iapetus, Saturn’s third largest moon.

The researchers said about 99% of Chrysalis’ debris sank into Saturn’s atmosphere, while the remaining 1% remained in orbit, leaving a debris-strewn ring in its wake that formed the planet’s iconic great rings.

“Just like the chrysalis of a butterfly, this satellite was very dormant and suddenly became active and the rings appeared,” said Jack Wisdom, lead author and professor of planetary sciences at MIT.

Saturn's rings show their distinctive colors in this view taken on August 22, 2009 by NASA's Cassini spacecraft.

Saturn’s rings show their distinctive colors in this view taken by NASA’s Cassini spacecraft on August 22, 2009.NASA/JPL-Caltech/Space Science Institute

Planetary scientists have long suspected that Saturn’s tilt may have come from gravitational interactions with Neptune. To gather information about the planet’s tilt, the researchers used simulations to calculate Saturn’s moment of inertia, which relates how much force it would take to tip the planet on its side. They found that while Saturn may once have been gravitationally in sync with Neptune, something changed about 160 million years ago that removed Saturn from Neptune’s influence.

“Then we looked to find ways to get Saturn out of Neptune’s coordination,” Wisdom said. Resonance occurs when two celestial bodies continue to realign after a certain number of orbits. They theorized that an ancient moon, Chrysalis, could have held Saturn under Neptune’s influence until it disintegrated, allowing Saturn to move just out of sync with Neptune.

Wisdom stressed that more data will be needed to see if the theory holds. “It’s a pretty good story, but like any other result, it should be looked at by others,” Wisdom said. He added that the small moon appears to have acted as a butterfly in its chrysalis stage, with its rings emerging once it was torn apart by Saturn’s gravity.

Read the original article on Business Insider

Leave a Reply

Your email address will not be published.