Can missing satellites explain Saturn’s tilted axis and rings? | sorae portal site to the universe

Massachusetts Institute of Technology (MIT)Professor Jack WisdomThe research team is led byA new hypothesis that can explain the tilt of Saturn’s rotation axis and the existence of ringspublish The key is that although it once orbited Saturn,One satellite is now missingin.

According to the research team, when the moon existed, there was Saturninteraction with NeptuneEchoed by this, the axis of rotation began to tilt. However, because the interaction between the satellites disrupted the orbit and it came too close to Saturn,the satellite collapsed.from some of the wreckagering formedOn the other hand, Saturn and Neptune are said to be out of resonance.

The possibility that one satellite with a diameter of about 1,500 km has been lost from the Saturn system

5 years ago from nowSeptember 15, 2017.National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA)Saturn probe “Cassini”it has been 13 years since it arrived at Saturn in June 2004 and 20 years since it was launched in October 1997.Last day of the missionwelcome Last observation to pass under Saturn’s cycles a total of 22 times“Grand Finale”Cassini, which has been doing this since April 2017, said on this day it would not contaminate Saturn’s moons with Earth microbes that might have been on the spacecraft.enter Saturn’s atmosphere onThen it disappears and the mission ends.

[▲ Fideo “NASA yn Sadwrn: Grand Finale Cassini” (Saesneg)]
（Credit: NASA/JPL-Caltech）

Saturn’s greatest characteristica giant ringit is believed to be 4 billion years or more, but in 2019, based on data obtained by Cassini observations,Saturn’s rings may have formed only about 100 million years agoResearch results have been published showing that if this is true, Saturn did not yet have rings when the first dinosaurs appeared on Earth. However, how the rings were formed remains a mystery.

Wisdom and othersA satellite that once existed collapsed because it got too close to Saturnand thatPart of the wreckage became the present ringI think. Assuming that the big flower called Saturn’s rings had blossomed like a butterfly emerging from a chrysalis, the research team called the satellite“Crysalis”(Chrysalis, an English word meaning pupa).

[▲SadwrnagymerwydganyllongofodCassiniCymerwydymmisEbrill2016(Credyd:NASA/JPL-Caltech/SpaceScienceInstitute)】

Canfu’r tîm ymchwil mai Chrysalis yw trydedd lloeren fwyaf Sadwrn heddiw.Amcangyfrifir ei fod yn debyg i Iapetus (tua 1470 km mewn diamedr)gwneud. Syrthiodd tua 99 y cant o falurion Chrysalis i Sadwrn ar ôl iddo ddymchwel, a ffurfiwyd y modrwyau o’r malurion a oedd ar ôl.

■ Roedd Sadwrn yn asio â Neifion pan oedd Chrysalis yn bodoli

Nid oedd doethineb a gyrhaeddodd lloeren goll Saturn yn ceisio tarddiad y fodrwy o’r dechrau, ond yn wreiddiolPam mae echel cylchdro Sadwrn yn gogwyddoRoeddwn i’n chwilio am

cysawd yr haulcewri nwy a chewri rhewmewn perthynas â’r awyren orbitol (yr awyren a dynnir gan orbit y chwyldro)tilt o echel cylchdroamrywio.yw’r blaned fwyaf yng nghysawd yr haulMae echel cylchdro Jupiter tua 3 graddond heb ogwyddo,Mae echel cylchdro Sadwrn tua 27 graddpwysoMae echel cylchdro Wranws ​​bron i’r ochr, tua 98 graddyn gogwyddo hefyd, ond mae hyn wedi digwydd yn y gorffennolgwrthdaro mawrcredir ei fod yn perthyn.

[▲ Fideo yn cymharu cylchdro wyth planed yng nghysawd yr haul]
（Credit: James O’Donoghue; Images from: NASA/Hubble/Cassini/JHUAPL/SSI/SwRI/Solar System Scope Processing）

According to the research team, in the case of Saturn, the precession of the rotational axis appears to be synchronized with the precession of Neptune’s orbital axis (the axis that extends perpendicularly from the orbital plane).Saturn resonates by giving gravity to Neptuneand consequentlyIs the axis of rotation tilted?It has been thought. Saturn’s axis of rotation, which was slightly tilted to begin with, became greatly tilted due to resonance with Neptune.

But this ideaSaturn’s angular momentum is not exactly knownThere is said to be a problem. As Saturn’s angular momentum is one of the factors that control the influence of Neptune’s resonance, Saturn’s angular momentum must be determined in order to fully understand the relationship between Saturn and Neptune. Therefore, the research team modeled the interior of Saturn, and based on observational data of the gravitational field obtained in Cassini’s Grand Finale,a moment of inertia of SaturnI tried to find out

.

* Angular momentum is the product of angular velocity and momentum of inertia.As a result of the analysis,Saturn’s angular momentum is too small to resonate with NeptuneIt turns out. It seems that Saturn and Neptune, at least now, are not in resonance. anyway,Assuming that Saturn has another moonif,Calculations suggest that Saturn and Neptune may have been in resonance in the past

was also shown.Then the research teamWhy is Saturn Out of Resonance with Neptune?consider. As a result of repeating many simulations, it was found that in the past Saturn was approximately the same size as Iapetus.there is another satelliteAlthough I amIt may have gone out of resonance with Neptune because it lost its moonit was found to be the highest. at the same time,The tilting of Saturn’s axis of rotation is the result of resonance with Neptune

[▲IapetusagymerwydganyllongofodCassiniCymerwydymmisMedi2007(Credyd:NASA/JPL/SpaceScienceInstitute)】

[▲ Iapetus a gymerwyd gan y llong ofod Cassini. Cymerwyd ym mis Medi 2007 (Credyd: NASA/JPL/Space Science Institute)]This satellite was lost becauseThe orbit changes in resonance with the moon Titan*, which continues to move away from Saturn.It is believed to be because it came close to Saturn. Based on the speed at which Titan is moving away from Saturn, the researchers estimated that time.200 million to 100 million years agowhich has been estimated in recent yearscoincides with the time of ring formation

Do.

*… Saturn’s largest satellite, with a diameter of about 5,150 km. Cassini’s observations show that it is moving away from Saturn at a rate of about 11 centimeters per year.It is the result of billions of years of resonance with Neptune.the tilt of Saturn’s rotation axisand he was very young compared to the body of SaturnFormation of Saturn’s ringsbut,Both can be explained by one satellite and its fall

Will be. This satellite is called Chrysalis. The research team hopes to support the theory by measuring the movements of Saturn and its moons and Neptune more accurately.

RELATED: Saturn’s 27-degree tilted axis may continue to tilt

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• Image Credit: NASA/JPL-Caltech/Space Science Foundation
• MIT – Saturn’s rings and tilt could be the product of an ancient lost moon

UC Berkeley – Chrysalis, the lost moon that gave Saturn rings