A ring system is a disc or torus orbiting an astronomical object that is composed of solid material such as gas, dust , meteoroids , planetoids or moonlets and stellar objects.
153-499: The rings of Saturn are the most extensive and complex ring system of any planet in the Solar System . They consist of countless small particles, ranging in size from micrometers to meters , that orbit around Saturn . The ring particles are made almost entirely of water ice, with a trace component of rocky material . There is still no consensus as to their mechanism of formation. Although theoretical models indicated that
306-413: A liberal education , studying languages, music , history , geography , mathematics , logic , and rhetoric , alongside dancing , fencing and horse riding . In 1644, Huygens had as his mathematical tutor Jan Jansz Stampioen , who assigned the 15-year-old a demanding reading list on contemporary science. Descartes was later impressed by his skills in geometry, as was Mersenne, who christened him
459-1286: A substellar object with a circumstellar disk or massive rings transiting the star. This substellar object, dubbed " J1407b ", is most likely a free-floating brown dwarf or rogue planet several times the mass of Jupiter. The circumstellar disk or ring system of J1407b is about 0.6 astronomical units (90,000,000 km; 56,000,000 mi) in radius. J1407b's transit of V1400 Centauri revealed gaps and density variations within its disk or ring system, which has been interpreted as hints of exomoons or exoplanets forming around J1407b. Solar System → Local Interstellar Cloud → Local Bubble → Gould Belt → Orion Arm → Milky Way → Milky Way subgroup → Local Group → Local Sheet → Virgo Supercluster → Laniakea Supercluster → Local Hole → Observable universe → Universe Each arrow ( → ) may be read as "within" or "part of". Christiaan Huygens Christiaan Huygens , Lord of Zeelhem , FRS ( / ˈ h aɪ ɡ ən z / HY -gənz , US also / ˈ h ɔɪ ɡ ən z / HOY -gənz ; Dutch: [ˈkrɪstijaːn ˈɦœyɣə(n)s] ; also spelled Huyghens ; Latin : Hugenius ; 14 April 1629 – 8 July 1695)
612-420: A better hypothesis than his own and De corpore saturni was never published. Robert Hooke was another early observer of the rings of Saturn, and noted the casting of shadows on the rings. Huygens began grinding lenses with his father Constantijn in 1655 and was able to observe Saturn with greater detail using a 43× power refracting telescope that he designed himself. He was the first to suggest that Saturn
765-594: A broad range of correspondents, though with some difficulty after 1648 due to the five-year Fronde in France. Visiting Paris in 1655, Huygens called on Ismael Boulliau to introduce himself, who took him to see Claude Mylon . The Parisian group of savants that had gathered around Mersenne held together into the 1650s, and Mylon, who had assumed the secretarial role, took some trouble to keep Huygens in touch. Through Pierre de Carcavi Huygens corresponded in 1656 with Pierre de Fermat, whom he admired greatly. The experience
918-534: A career. Huygens generally wrote in French or Latin. In 1646, while still a college student at Leiden, he began a correspondence with his father's friend, Marin Mersenne , who died soon afterwards in 1648. Mersenne wrote to Constantijn on his son's talent for mathematics, and flatteringly compared him to Archimedes on 3 January 1647. The letters show Huygens's early interest in mathematics. In October 1646 there
1071-402: A collection of solutions to classical problems at the end of the work under the title Illustrium Quorundam Problematum Constructiones ( Construction of some illustrious problems ). Huygens became interested in games of chance after he visited Paris in 1655 and encountered the work of Fermat, Blaise Pascal and Girard Desargues years earlier. He eventually published what was, at the time,
1224-621: A complete explanation of the rectilinear propagation and diffraction effects of light in 1821. Today this principle is known as the Huygens–Fresnel principle . Huygens invented the pendulum clock in 1657, which he patented the same year. His horological research resulted in an extensive analysis of the pendulum in Horologium Oscillatorium (1673), regarded as one of the most important 17th century works on mechanics. While it contains descriptions of clock designs, most of
1377-477: A considerable risk to the New Horizons spacecraft. However, this possibility was ruled out when New Horizons failed to detect any dust rings around Pluto. 10199 Chariklo , a centaur , was the first minor planet discovered to have rings. It has two rings , perhaps due to a collision that caused a chain of debris to orbit it. The rings were discovered when astronomers observed Chariklo passing in front of
1530-462: A deduction that the pattern may have originated in late 1983 with the impact of a cloud of debris (with a mass of ≈10 kg) from a disrupted comet that tilted the rings out of the equatorial plane. A similar spiral pattern in Jupiter's main ring has been attributed to a perturbation caused by impact of material from Comet Shoemaker-Levy 9 in 1994. The C Ring is a wide but faint ring located inward of
1683-428: A distance of 4,057 ± 6 km , approximately 7.5 times the radius of Quaoar and more than double the distance of its Roche limit. The inner ring orbits at a distance of 2,520 ± 20 km , approximately 4.6 times the radius of Quaoar and also beyond its Roche limit. The outer ring appears to be inhomogeneous, containing a thin, dense section as well as a broader, more diffuse section. Because all giant planets of
SECTION 10
#17327799902521836-585: A distinctive band around the Earth's equator at that time. The presence of this ring may have led to significant shielding of Earth from sun's rays and a severe cooling event, thus causing the Hirnantian glaciation , the coldest known period of the last 450 million years. Reports in March 2008 suggested that Saturn's moon Rhea may have its own tenuous ring system , which would make it the only moon known to have
1989-473: A form of commitment scheme to lay claim to new discoveries before their results were ready for publication. Galileo used the anagram " smaismrmilmepoetaleumibunenugttauiras " for Altissimum planetam tergeminum observavi ("I have observed the most distant planet to have a triple form") for discovering the rings of Saturn. In 1657 Christopher Wren became Professor of Astronomy at Gresham College, London. He had been making observations of
2142-559: A full cycle of rotation. His approach was thus equivalent to the principle of virtual work . Huygens was also the first to recognize that, for these homogeneous solids, their specific weight and their aspect ratio are the essentials parameters of hydrostatic stability . Huygens was the leading European natural philosopher between Descartes and Newton. However, unlike many of his contemporaries, Huygens had no taste for grand theoretical or philosophical systems and generally avoided dealing with metaphysical issues (if pressed, he adhered to
2295-482: A gaseous nebula. This would explain the scarcity of rocky material within the rings. The rings would initially have been much more massive (≈1,000 times) and broader than at present; material in the outer portions of the rings would have coalesced into the innermost moons of Saturn (those closest to Saturn), out to Tethys , also explaining the lack of rocky material in the composition of most of these moons. Subsequent collisional or cryovolcanic evolution of Enceladus, which
2448-565: A larger audience until the publication of De Motu Corporum ex Percussione ( Concerning the motion of colliding bodies ) in 1703. In addition to his mathematical and mechanical works, Huygens made important scientific discoveries: he was the first to identify Titan as one of Saturn's moons in 1655, invented the pendulum clock in 1657, and explained Saturn's strange appearance as due to a ring in 1659; all these discoveries brought him fame across Europe. On 3 May 1661, Huygens, together with astronomer Thomas Streete and Richard Reeve, observed
2601-530: A meeting at Gresham College . Shortly afterwards, he reevaluated Boyle's experimental design and developed a series of experiments meant to test a new hypothesis. It proved a yearslong process that brought to the surface a number of experimental and theoretical issues, and which ended around the time he became a Fellow of the Royal Society. Despite the replication of results of Boyle's experiments trailing off messily, Huygens came to accept Boyle's view of
2754-479: A moon that large was during the Late Heavy Bombardment some four billion years ago. A more recent variant of this type of theory by R. M. Canup is that the rings could represent part of the remains of the icy mantle of a much larger, Titan-sized, differentiated moon that was stripped of its outer layer as it spiraled into the planet during the formative period when Saturn was still surrounded by
2907-469: A moon that was disrupted by tidal stresses when it passed within the planet's Roche limit. Most rings were thought to be unstable and to dissipate over the course of tens or hundreds of millions of years, but it now appears that Saturn's rings might be quite old, dating to the early days of the Solar System. Fainter planetary rings can form as a result of meteoroid impacts with moons orbiting around
3060-414: A more complicated set. It is primarily acted on by the 7:6 resonance with Janus and Epimetheus , with other contributions from the 5:3 resonance with Mimas and various resonances with Prometheus and Pandora . Other orbital resonances also excite many spiral density waves in the A Ring (and, to a lesser extent, other rings as well), which account for most of its structure. These waves are described by
3213-513: A planetary ring in about 50 million years. Its low orbit, with an orbital period that is shorter than a Martian day, is decaying due to tidal deceleration . Jupiter's ring system was the third to be discovered, when it was first observed by the Voyager 1 probe in 1979, and was observed more thoroughly by the Galileo orbiter in the 1990s. Its four main parts are a faint thick torus known as
SECTION 20
#17327799902523366-404: A ring mass of 0.1%−10% of the centaur's mass is predicted. Ring formation from an undifferentiated body is less likely. The rings would be composed mostly or entirely of material from the parent body's icy mantle. After forming, the ring would spread laterally, leading to satellite formation from whatever portion of it spreads beyond the centaur's Roche Limit. Satellites could also form directly from
3519-468: A ring particle is determined by the specific strength of the material it is made of, its density, and the tidal force at its altitude. The tidal force is proportional to the average density inside the radius of the ring, or to the mass of the planet divided by the radius of the ring cubed. It is also inversely proportional to the square of the orbital period of the ring. Some planetary rings are influenced by shepherd moons , small moons that orbit near
3672-492: A ring system for a period of 40 million years, starting from the middle of the Ordovician period (around 466 million years ago). This ring system may have originated from a large asteroid that passed by Earth at this time and had a significant amount of debris stripped by Earth's gravitational pull, forming a ring system. Evidence for this ring comes from impact craters from the Ordovician meteor event appearing to cluster in
3825-576: A ring system. A later study published in 2010 revealed that imaging of Rhea by the Cassini spacecraft was inconsistent with the predicted properties of the rings, suggesting that some other mechanism is responsible for the magnetic effects that had led to the ring hypothesis. Prior to the arrival of New Horizons , some astronomers hypothesized that Pluto and Charon might have a circumbinary ring system created from dust ejected off of Pluto's small outer moons in impacts. A dust ring would have posed
3978-443: A segment of a circle, resulting in a faster and accurate approximation of the circle quadrature. From these theorems, Huygens obtained two set of values for π : the first between 3.1415926 and 3.1415927, and the second between 3.1415926533 and 3.1415926538. Huygens also showed that, in the case of the hyperbola , the same approximation with parabolic segments produces a quick and simple method to calculate logarithms . He appended
4131-438: A series of tiny ringlets as many think, but are more of a disk with varying density. They consist mostly of water ice and trace amounts of rock , and the particles range in size from micrometers to meters. Uranus's ring system lies between the level of complexity of Saturn's vast system and the simpler systems around Jupiter and Neptune. They were discovered in 1977 by James L. Elliot , Edward W. Dunham, and Jessica Mink . In
4284-565: A sharp cutoff in ring density. Many of the other gaps between ringlets within the Cassini Division, however, are unexplained. Discovered in 1981 through images sent back by Voyager 2, the Huygens Gap is located at the inner edge of the Cassini Division. It contains the dense, eccentric Huygens Ringlet in the middle. This ringlet exhibits irregular azimuthal variations of geometrical width and optical depth, which may be caused by
4437-465: A single or three crossings occurring in each such occasion. The most recent ring plane crossings were on 22 May 1995, 10 August 1995, 11 February 1996 and 4 September 2009; upcoming events will occur on 23 March 2025, 15 October 2038, 1 April 2039 and 9 July 2039. Favorable ring plane crossing viewing opportunities (with Saturn not close to the Sun) only come during triple crossings. Saturn's equinoxes , when
4590-645: A telescope with two lenses to diminish the amount of dispersion . As a mathematician, Huygens developed the theory of evolutes and wrote on games of chance and the problem of points in Van Rekeningh in Spelen van Gluck , which Frans van Schooten translated and published as De Ratiociniis in Ludo Aleae (1657). The use of expected values by Huygens and others would later inspire Jacob Bernoulli's work on probability theory . Christiaan Huygens
4743-719: A vain mission to meet the French Foreign Minister Arnauld de Pomponne . Leibniz was working on a calculating machine at the time and, after a short visit to London in early 1673, he was tutored in mathematics by Huygens until 1676. An extensive correspondence ensued over the years, in which Huygens showed at first reluctance to accept the advantages of Leibniz's infinitesimal calculus . Huygens moved back to The Hague in 1681 after suffering another bout of serious depressive illness. In 1684, he published Astroscopia Compendiaria on his new tubeless aerial telescope . He attempted to return to France in 1685 but
Rings of Saturn - Misplaced Pages Continue
4896-402: Is 60,300 km (37,500 mi) (see Major subdivisions ). With an estimated local thickness of as little as 10 metres (32' 10") and as much as 1 km (1093 yards), they are composed of 99.9% pure water ice with a smattering of impurities that may include tholins or silicates . The main rings are primarily composed of particles smaller than 10 m. Cassini directly measured the mass of
5049-525: Is a region 4,800 km (3,000 mi) in width between Saturn's A Ring and B Ring . It was discovered in 1675 by Giovanni Cassini at the Paris Observatory using a refracting telescope that had a 2.5-inch objective lens with a 20-foot-long focal length and a 90x magnification . From Earth it appears as a thin black gap in the rings. However, Voyager discovered that the gap is itself populated by ring material bearing much similarity to
5202-564: Is about 1,000 times closer than the Moon is to Earth. In addition, astronomers suspect there could be a moon orbiting amidst the ring debris. If these rings are the leftovers of a collision as astronomers suspect, this would give fodder to the idea that moons (such as the Moon) form through collisions of smaller bits of material. Chariklo's rings have not been officially named, but the discoverers have nicknamed them Oiapoque and Chuí, after two rivers near
5355-503: Is also present. The O 2 and H 2 atmospheres are so sparse that if the entire atmosphere were somehow condensed onto the rings, it would be about one atom thick. The rings also have a similarly sparse OH (hydroxide) atmosphere. Like the O 2 , this atmosphere is produced by the disintegration of water molecules, though in this case the disintegration is done by energetic ions that bombard water molecules ejected by Saturn's moon Enceladus . This atmosphere, despite being extremely sparse,
5508-505: Is another of these moons, might then have caused selective loss of ice from this moon, raising its density to its current value of 1.61 g/cm, compared to values of 1.15 for Mimas and 0.97 for Tethys. The idea of massive early rings was subsequently extended to explain the formation of Saturn's moons out to Rhea. If the initial massive rings contained chunks of rocky material (>100 km; 60 miles across) as well as ice, these silicate bodies would have accreted more ice and been expelled from
5661-465: Is slightly elliptical rather than circular. This ringlet is also called the Titan Ringlet as it is governed by an orbital resonance with the moon Titan . At this location within the rings, the length of a ring particle's apsidal precession is equal to the length of Titan's orbital motion, so that the outer end of this eccentric ringlet always points towards Titan. The Maxwell Gap lies within
5814-501: Is that this moon disintegrated after being struck by a large comet or asteroid . The second theory is that the rings were never part of a moon, but are instead left over from the original nebular material from which Saturn formed. A more traditional version of the disrupted-moon theory is that the rings are composed of debris from a moon 400 to 600 km (200 to 400 miles) in diameter, slightly larger than Mimas . The last time there were collisions large enough to be likely to disrupt
5967-480: Is the suspension bridge and the demonstration that a hanging chain is not a parabola , as Galileo thought. Huygens would later label that curve the catenaria ( catenary ) in 1690 while corresponding with Gottfried Leibniz . In the next two years (1647–48), Huygens's letters to Mersenne covered various topics, including a mathematical proof of the law of free fall , the claim by Grégoire de Saint-Vincent of circle quadrature , which Huygens showed to be wrong,
6120-450: Is the innermost ring, and is very faint. In 1980, Voyager 1 detected within this ring three ringlets designated D73, D72 and D68, with D68 being the discrete ringlet nearest to Saturn. Some 25 years later, Cassini images showed that D72 had become significantly broader and more diffuse, and had moved planetward by 200 km (100 miles). Present in the D Ring is a finescale structure with waves 30 km (20 miles) apart. First seen in
6273-412: Is tilted at an angle of 27 degrees to the more visible rings orbiting above Saturn's equator. In September 2023, astronomers reported studies suggesting that the rings of Saturn may have resulted from the collision of two moons "a few hundred million years ago". Galileo Galilei was the first to observe the rings of Saturn in 1610 using his telescope, but was unable to identify them as such. He wrote to
Rings of Saturn - Misplaced Pages Continue
6426-502: Is well within Haumea's Roche limit , which would lie at a radius of about 4,400 km if Haumea were spherical (being nonspherical pushes the limit out farther). In 2023, astronomers announced the discovery of a widely separated ring around the dwarf planet and Kuiper belt object Quaoar . Further analysis of the occultation data uncovered a second inner, fainter ring. Both rings display unusual properties. The outer ring orbits at
6579-497: The B Ring . It was discovered in 1850 by William and George Bond , though William R. Dawes and Johann Galle also saw it independently. William Lassell termed it the "Crepe Ring" because it seemed to be composed of darker material than the brighter A and B Rings. Its vertical thickness is estimated at 5 metres (16'), its mass at around 1.1 × 10 kg, and its optical depth varies from 0.05 to 0.12. That is, between 5 and 12 percent of light shining perpendicularly through
6732-514: The C Ring . The division may appear bright in views of the unlit side of the rings, since the relatively low density of material allows more light to be transmitted through the thickness of the rings (see second image in gallery ). The inner edge of the Cassini Division is governed by a strong orbital resonance. Ring particles at this location orbit twice for every orbit of the moon Mimas . The resonance causes Mimas' pulls on these ring particles to accumulate, destabilizing their orbits and leading to
6885-659: The Cartesian philosophy of his time). Instead, Huygens excelled in extending the work of his predecessors, such as Galileo, to derive solutions to unsolved physical problems that were amenable to mathematical analysis. In particular, he sought explanations that relied on contact between bodies and avoided action at a distance . In common with Robert Boyle and Jacques Rohault , Huygens advocated an experimentally oriented, mechanical natural philosophy during his Paris years. Already in his first visit to England in 1661, Huygens had learnt about Boyle's air pump experiments during
7038-512: The Cassini Division . This division is a 4,800-kilometre-wide (3,000 mi) region between the A ring and B Ring . In 1787, Pierre-Simon Laplace proved that a uniform solid ring would be unstable and suggested that the rings were composed of a large number of solid ringlets. In 1859, James Clerk Maxwell demonstrated that a nonuniform solid ring, solid ringlets or a continuous fluid ring would also not be stable, indicating that
7191-641: The Cassini Titan Radar Mapper , which focused on analyzing the proportion of rocky silicates within this ring. If much of this material was contributed by a recently disrupted centaur or moon, the age of this ring could be on the order of 100 million years or less. On the other hand, if the material came primarily from micrometeoroid influx, the age would be closer to a billion years. The Cassini UVIS team, led by Larry Esposito , used stellar occultation to discover 13 objects, ranging from 27 metres (89') to 10 km (6 miles) across, within
7344-456: The Duke of Tuscany that "The planet Saturn is not alone, but is composed of three, which almost touch one another and never move nor change with respect to one another. They are arranged in a line parallel to the zodiac , and the middle one (Saturn itself) is about three times the size of the lateral ones." He also described the rings as Saturn's "ears". In 1612 the Earth passed through the plane of
7497-540: The Encke Gap . A narrower gap 2% of the ring width from the outer edge is called the Keeler Gap . The thickness of the A Ring is estimated to be 10 to 30 m, its surface density from 35 to 40 g/cm and its total mass as 4 to 5 × 10 kg (just under the mass of Hyperion ). Its optical depth varies from 0.4 to 0.9. Similarly to the B Ring, the A Ring's outer edge is maintained by orbital resonances, albeit in this case
7650-470: The F ring . They are translucent, suggesting they are temporary aggregates of ice boulders a few meters across. Esposito believes this to be the basic structure of the Saturnian rings, particles clumping together, then being blasted apart. Research based on rates of infall into Saturn favors a younger ring system age of hundreds of millions of years. Ring material is continually spiraling down into Saturn;
7803-476: The Royal Society of London elected Huygens a Fellow in 1663, making him its first foreign member when he was just 34 years old. The Montmor Academy , started in the mid-1650s, was the form the old Mersenne circle took after his death. Huygens took part in its debates and supported those favouring experimental demonstration as a check on amateurish attitudes. He visited Paris a third time in 1663; when
SECTION 50
#17327799902527956-536: The Second Anglo-Dutch War , was guarded. The war ended in 1667, and Huygens announced his results to the Royal Society in 1668. He later published them in the Journal des Sçavans in 1669. In 1659 Huygens found the constant of gravitational acceleration and stated what is now known as the second of Newton's laws of motion in quadratic form. He derived geometrically the now standard formula for
8109-558: The Voyager spacecraft discovered that the rings have an intricate structure of thousands of thin gaps and ringlets. This structure is thought to arise, in several different ways, from the gravitational pull of Saturn's many moons. Some gaps are cleared out by the passage of tiny moonlets such as Pan , many more of which may yet be discovered, and some ringlets seem to be maintained by the gravitational effects of small shepherd satellites (similar to Prometheus and Pandora 's maintenance of
8262-405: The a priori attitude of Descartes, but neither would he accept aspects of gravitational attractions that were not attributable in principle to contact between particles. The approach used by Huygens also missed some central notions of mathematical physics, which were not lost on others. In his work on pendulums Huygens came very close to the theory of simple harmonic motion ; the topic, however,
8415-599: The asteroid belt or Kuiper belt , or rings of interplanetary dust , such as around the Sun at distances of Mercury , Venus , and Earth, in mean motion resonance with these planets. Evidence suggests that ring systems may also be found around other types of astronomical objects, including moons and brown dwarfs . In the Solar System , all four giant planets ( Jupiter , Saturn, Uranus , and Neptune ) have ring systems. Ring systems around minor planets have also been discovered via occultations. Some studies even theorize that
8568-479: The centre of gravity of the system remains the same in velocity and direction, which Huygens called the conservation of "quantity of movement" . While others at the time were studying impact, Huygens's theory of collisions was more general. These results became the main reference point and the focus for further debates through correspondence and in a short article in Journal des Sçavans but would remain unknown to
8721-402: The centrifugal force , exerted on an object when viewed in a rotating frame of reference , for instance when driving around a curve. In modern notation: with m the mass of the object, ω the angular velocity , and r the radius . Huygens collected his results in a treatise under the title De vi Centrifuga , unpublished until 1703, where the kinematics of free fall were used to produce
8874-555: The moons of Saturn . Other gaps remain unexplained. Stabilizing resonances, on the other hand, are responsible for the longevity of several rings, such as the Titan Ringlet and the G Ring . Well beyond the main rings is the Phoebe ring , which is presumed to originate from Phoebe and thus share its retrograde orbital motion. It is aligned with the plane of Saturn's orbit. Saturn has an axial tilt of 27 degrees, so this ring
9027-523: The pendulum clock , the most accurate timekeeper for almost 300 years. A talented mathematician and physicist, his works contain the first idealization of a physical problem by a set of mathematical parameters , and the first mathematical and mechanistic explanation of an unobservable physical phenomenon. Huygens first identified the correct laws of elastic collision in his work De Motu Corporum ex Percussione , completed in 1656 but published posthumously in 1703. In 1659, Huygens derived geometrically
9180-453: The revocation of the Edict of Nantes precluded this move. His father died in 1687, and he inherited Hofwijck, which he made his home the following year. On his third visit to England, Huygens met Isaac Newton in person on 12 June 1689. They spoke about Iceland spar , and subsequently corresponded about resisted motion. Huygens returned to mathematical topics in his last years and observed
9333-540: The Øresund to visit Descartes in Stockholm . This did not happen as Descartes had died in the interim. Although his father Constantijn had wished his son Christiaan to be a diplomat, circumstances kept him from becoming so. The First Stadtholderless Period that began in 1650 meant that the House of Orange was no longer in power, removing Constantijn's influence. Further, he realized that his son had no interest in such
SECTION 60
#17327799902529486-439: The "halo"; a thin, relatively bright main ring; and two wide, faint "gossamer rings". The system consists mostly of dust. Saturn's rings are the most extensive ring system of any planet in the Solar System, and thus have been known to exist for quite some time. Galileo Galilei first observed them in 1610, but they were not accurately described as a disk around Saturn until Christiaan Huygens did so in 1655. The rings are not
9639-449: The "new Archimedes ." At sixteen years of age, Constantijn sent Huygens to study law and mathematics at Leiden University , where he studied from May 1645 to March 1647. Frans van Schooten was an academic at Leiden from 1646, and became a private tutor to Huygens and his elder brother, Constantijn Jr., replacing Stampioen on the advice of Descartes. Van Schooten brought Huygens's mathematical education up to date, introducing him to
9792-795: The 1930s. The pendulum clock was much more accurate than the existing verge and foliot clocks and was immediately popular, quickly spreading over Europe. Clocks prior to this would lose about 15 minutes per day, whereas Huygens's clock would lose about 15 seconds per day. Although Huygens patented and contracted the construction of his clock designs to Salomon Coster in The Hague, he did not make much money from his invention. Pierre Séguier refused him any French rights, while Simon Douw in Rotterdam and Ahasuerus Fromanteel in London copied his design in 1658. The oldest known Huygens-style pendulum clock
9945-427: The 19th century is that the rings were once a moon of Saturn (named Veritas, after a Roman goddess who hid in a well). According to the theory, the moon's orbit decayed until it was close enough to be ripped apart by tidal forces (see Roche limit ). Numerical simulations carried out in 2022 support this theory; the authors of that study proposed the name " Chrysalis " for the destroyed moon. A variation on this theory
10098-438: The A, B and C rings. It is a small fraction of the total mass of Saturn (about 0.25 ppb ). Earlier Voyager observations of density waves in the A and B rings and an optical depth profile had yielded a mass of about 0.75 Mimas masses, with later observations and computer modeling suggesting that was an underestimate. Although the largest gaps in the rings, such as the Cassini Division and Encke Gap , can be seen from Earth,
10251-420: The B Ring may be massive enough to have diluted infalling material and thus avoided substantial darkening over the age of the Solar System. Ring material may be recycled as clumps form within the rings and are then disrupted by impacts. This would explain the apparent youth of some of the material within the rings. Evidence suggesting a recent origin of the C ring has been gathered by researchers analyzing data from
10404-409: The B Ring's surface density is in the range of 40 to 140 g/cm, lower than previously believed, and that the ring's optical depth has little correlation with its mass density (a finding previously reported for the A and C rings). The total mass of the B Ring was estimated to be somewhere in the range of 7 to 24 × 10 kg. This compares to a mass for Mimas of 37.5 × 10 kg. Until 1980, the structure of
10557-416: The Cassini Division (discovered in 1675 by Giovanni Domenico Cassini ). Along with the C Ring, which was discovered in 1850 and is similar in character to the Cassini Division, these regions constitute the main rings . The main rings are denser and contain larger particles than the tenuous dusty rings . The latter include the D Ring, extending inward to Saturn's cloud tops, the G and E Rings and others beyond
10710-512: The Circle , showing that the ratio of the circumference to its diameter or pi ( π ) must lie in the first third of that interval. Using a technique equivalent to Richardson extrapolation , Huygens was able to shorten the inequalities used in Archimedes's method; in this case, by using the centre of the gravity of a segment of a parabola, he was able to approximate the centre of gravity of
10863-452: The Earth may have had a ring system during the mid-late Ordovician period. There are three ways that thicker planetary rings have been proposed to have formed: from material originating from the protoplanetary disk that was within the Roche limit of the planet and thus could not coalesce to form moons, from the debris of a moon that was disrupted by a large impact, or from the debris of
11016-588: The English lecturer John Pell . His time in Breda ended around the time when his brother Lodewijk, who was enrolled at the school, duelled with another student. Huygens left Breda after completing his studies in August 1649 and had a stint as a diplomat on a mission with Henry, Duke of Nassau . It took him to Bentheim , then Flensburg . He took off for Denmark, visited Copenhagen and Helsingør , and hoped to cross
11169-454: The F ring). Other gaps arise from resonances between the orbital period of particles in the gap and that of a more massive moon further out; Mimas maintains the Cassini Division in this manner. Still more structure in the rings consists of spiral waves raised by the inner moons' periodic gravitational perturbations at less disruptive resonances. Data from the Cassini space probe indicate that
11322-538: The French Académie was not always easy, and in 1670 Huygens, seriously ill, chose Francis Vernon to carry out a donation of his papers to the Royal Society in London, should he die. However, the aftermath of the Franco-Dutch War (1672–78), and particularly England's role in it, may have damaged his later relationship with the Royal Society. Robert Hooke , as a Royal Society representative, lacked
11475-674: The Montmor Academy closed down the next year, Huygens advocated for a more Baconian program in science. Two years later, in 1666, he moved to Paris on an invitation to fill a leadership position at King Louis XIV 's new French Académie des sciences . While at the Académie in Paris, Huygens had an important patron and correspondent in Jean-Baptiste Colbert , First Minister to Louis XIV. However, his relationship with
11628-417: The Solar System have rings, the existence of exoplanets with rings is plausible. Although particles of ice , the material that is predominant in the rings of Saturn , can only exist around planets beyond the frost line , within this line rings consisting of rocky material can be stable in the long term. Such ring systems can be detected for planets observed by the transit method by additional reduction of
11781-439: The Sun passes through the ring plane, are not evenly spaced. The sun passes south to north through the ring plane when Saturn's heliocentric longitude is 173.6 degrees (e.g. 11 August 2009), about the time Saturn crosses from Leo to Virgo. 15.7 years later Saturn's longitude reaches 353.6 degrees and the sun passes to the south side of the ring plane. On each orbit the Sun is north of the ring plane for 15.7 Earth years, then south of
11934-507: The acoustical phenomenon now known as flanging in 1693. Two years later, on 8 July 1695, Huygens died in The Hague and was buried, like his father before him, in an unmarked grave at the Grote Kerk . Huygens never married. Huygens first became internationally known for his work in mathematics, publishing a number of important results that drew the attention of many European geometers. Huygens's preferred method in his published works
12087-454: The areas of hyperbolas, ellipses, and circles that paralleled Archimedes's work on conic sections, particularly his Quadrature of the Parabola . The second part included a refutation to Grégoire de Saint-Vincent's claims on circle quadrature, which he had discussed with Mersenne earlier. Huygens demonstrated that the centre of gravity of a segment of any hyperbola , ellipse , or circle
12240-531: The book is an analysis of pendular motion and a theory of curves . In 1655, Huygens began grinding lenses with his brother Constantijn to build refracting telescopes . He discovered Saturn's biggest moon, Titan, and was the first to explain Saturn's strange appearance as due to "a thin, flat ring, nowhere touching, and inclined to the ecliptic." In 1662 Huygens developed what is now called the Huygenian eyepiece ,
12393-475: The concepts of a "fair game" and equitable contract (i.e., equal division when the chances are equal), and extended the argument to set up a non-standard theory of expected values. His success in applying algebra to the realm of chance, which hitherto seemed inaccessible to mathematicians, demonstrated the power of combining Euclidean synthetic proofs with the symbolic reasoning found in the works of Viète and Descartes. Huygens included five challenging problems at
12546-669: The correct laws, including the conservation of the product of mass times the square of the speed for hard bodies, and the conservation of quantity of motion in one direction for all bodies. An important step was his recognition of the Galilean invariance of the problems. Huygens had worked out the laws of collision from 1652 to 1656 in a manuscript entitled De Motu Corporum ex Percussione , though his results took many years to be circulated. In 1661, he passed them on in person to William Brouncker and Christopher Wren in London. What Spinoza wrote to Henry Oldenburg about them in 1666, during
12699-442: The disrupted icy mantle. This formation mechanism predicts that roughly 10% of centaurs will have experienced potentially ring-forming encounters with giant planets. The composition of planetary ring particles varies, ranging from silicates to icy dust. Larger rocks and boulders may also be present, and in 2007 tidal effects from eight moonlets only a few hundred meters across were detected within Saturn's rings. The maximum size of
12852-466: The end of the book that became the standard test for anyone wishing to display their mathematical skill in games of chance for the next sixty years. People who worked on these problems included Abraham de Moivre , Jacob Bernoulli, Johannes Hudde , Baruch Spinoza , and Leibniz. Huygens had earlier completed a manuscript in the manner of Archimedes's On Floating Bodies entitled De Iis quae Liquido Supernatant ( About parts floating above liquids ). It
13005-455: The faster this infall, the shorter the lifetime of the ring system. One mechanism involves gravity pulling electrically charged water ice grains down from the rings along planetary magnetic field lines, a process termed 'ring rain'. This flow rate was inferred to be 432–2870 kg/s using ground-based Keck telescope observations; as a consequence of this process alone, the rings will be gone in ~ 292 +818 −124 million years. While traversing
13158-525: The finesse to handle the situation in 1673. The physicist and inventor Denis Papin was an assistant to Huygens from 1671. One of their projects, which did not bear fruit directly, was the gunpowder engine . Huygens made further astronomical observations at the Académie using the observatory recently completed in 1672. He introduced Nicolaas Hartsoeker to French scientists such as Nicolas Malebranche and Giovanni Cassini in 1678. The young diplomat Leibniz met Huygens while visiting Paris in 1672 on
13311-433: The first trans-Neptunian object found to have a ring system. The ring has a radius of about 2,287 km , a width of ≈ 70 km and an opacity of 0.5. The ring plane coincides with Haumea's equator and the orbit of its larger, outer moon Hi’iaka (which has a semimajor axis of ≈ 25,657 km ). The ring is close to the 3:1 resonance with Haumea's rotation, which is located at a radius of 2,285 ± 8 km . It
13464-460: The first generalized conception of force prior to Newton. The general idea for the centrifugal force, however, was published in 1673 and was a significant step in studying orbits in astronomy. It enabled the transition from Kepler's third law of planetary motion to the inverse square law of gravitation. Yet, the interpretation of Newton's work on gravitation by Huygens differed from that of Newtonians such as Roger Cotes : he did not insist on
13617-483: The first graph of a continuous distribution function under the assumption of a uniform death rate , and used it to solve problems in joint annuities . Contemporaneously, Huygens, who played the harpsichord , took an interest in Simon Stevin's theories on music; however, he showed very little concern to publish his theories on consonance , some of which were lost for centuries. For his contributions to science,
13770-404: The formula in classical mechanics for the centrifugal force in his work De vi Centrifuga , a decade before Newton . In optics, he is best known for his wave theory of light , which he described in his Traité de la Lumière (1690). His theory of light was initially rejected in favour of Newton's corpuscular theory of light , until Augustin-Jean Fresnel adapted Huygens's principle to give
13923-430: The gap between the C Ring and D73, the structure was found during Saturn's 2009 equinox to extend a radial distance of 19,000 km (12,000 miles) from the D Ring to the inner edge of the B Ring. The waves are interpreted as a spiral pattern of vertical corrugations of 2 to 20 m amplitude; the fact that the period of the waves is decreasing over time (from 60 km; 40 miles in 1995 to 30 km; 20 miles by 2006) allows
14076-488: The gap between the rings and planet in September 2017, the Cassini spacecraft detected an equatorial flow of charge-neutral material from the rings to the planet of 4,800–44,000 kg/s. Assuming this influx rate is stable, adding it to the continuous 'ring rain' process implies the rings may be gone in under 100 million years. The densest parts of the Saturnian ring system are the A and B Rings, which are separated by
14229-403: The inner or outer edges of a ringlet or within gaps in the rings. The gravity of shepherd moons serves to maintain a sharply defined edge to the ring; material that drifts closer to the shepherd moon's orbit is either deflected back into the body of the ring, ejected from the system, or accreted onto the moon itself. It is also predicted that Phobos , a moon of Mars, will break up and form into
14382-406: The last 100 million years, and may thus be between 10 million and 100 million years old. This recent origin scenario is based on a new, low mass estimate modeling of the rings' dynamical evolution, and measurements of the flux of interplanetary dust, which feed into an estimate of the rate of ring darkening over time. Since the rings are continually losing material, they would have been more massive in
14535-425: The light of the central star if their opacity is sufficient. As of 2024, two candidate extrasolar ring systems have been found by this method, around HIP 41378 f and K2-33b . Fomalhaut b was found to be large and unclearly defined when detected in 2008. This was hypothesized to either be due to a cloud of dust attracted from the dust disc of the star, or a possible ring system, though in 2020 Fomalhaut b itself
14688-483: The long-term variation in Chiron's brightness over time. Chiron's rings are suspected to be maintained by orbiting material ejected during seasonal outbursts, as a third partial ring detected in 2018 had become a full ring by 2022, with an outburst in between in 2021. A ring around Haumea , a dwarf planet and resonant Kuiper belt member , was revealed by a stellar occultation observed on 21 January 2017. This makes it
14841-475: The low-density regions of Saturn's rings. However, they are faint and dusty, much more similar in structure to those of Jupiter. The very dark material that makes up the rings is likely organics processed by radiation , like in the rings of Uranus. 20 to 70 percent of the rings are dust , a relatively high proportion. Hints of the rings were seen for decades prior to their conclusive discovery by Voyager 2 in 1989. A 2024 study suggests that Earth may have had
14994-406: The main ring system. These diffuse rings are characterised as "dusty" because of the small size of their particles (often about a μm ); their chemical composition is, like the main rings, almost entirely water ice. The narrow F Ring, just off the outer edge of the A Ring, is more difficult to categorize; parts of it are very dense, but it also contains a great deal of dust-size particles. The D Ring
15147-413: The mathematics of Thomas Hobbes . Persisting in trying to explain the errors Hobbes had fallen into, he made an international reputation. Huygens's next publication was De Circuli Magnitudine Inventa ( New findings in the measurement of the circle ), published in 1654. In this work, Huygens was able to narrow the gap between the circumscribed and inscribed polygons found in Archimedes's Measurement of
15300-479: The most coherent presentation of a mathematical approach to games of chance in De Ratiociniis in Ludo Aleae ( On reasoning in games of chance ). Frans van Schooten translated the original Dutch manuscript into Latin and published it in his Exercitationum Mathematicarum (1657). The work contains early game-theoretic ideas and deals in particular with the problem of points . Huygens took from Pascal
15453-554: The nearby 2:1 resonance with Mimas and the influence of the eccentric outer edge of the B-ring. There is an additional narrow ringlet just outside the Huygens Ringlet. The A Ring is the outermost of the large, bright rings. Its inner boundary is the Cassini Division and its sharp outer boundary is close to the orbit of the small moon Atlas . The A Ring is interrupted at a location 22% of the ring width from its outer edge by
15606-437: The northern and southern ends of Brazil. A second centaur, 2060 Chiron , has a constantly evolving disk of rings. Based on stellar-occultation data that were initially interpreted as resulting from jets associated with Chiron's comet-like activity, the rings are proposed to be 324 ± 10 km in radius, though their evolution does change the radius somewhat. Their changing appearance at different viewing angles can explain
15759-406: The outer edge of the B Ring contains vertical structures deviating up to 2.5 km (1½ miles) from the main ring plane, a significant deviation from the vertical thickness of the main A, B and C rings, which is generally only about 10 meters (about 30 feet). Vertical structures can be created by unseen embedded moonlets. A 2016 study of spiral density waves using stellar occultations indicated that
15912-550: The outer part of the C Ring. It also contains a dense non-circular ringlet, the Maxwell Ringlet. In many respects this ringlet is similar to the ε ring of Uranus . There are wave-like structures in the middle of both rings. While the wave in the ε ring is thought to be caused by Uranian moon Cordelia , no moon has been discovered in the Maxwell gap as of July 2008. The B Ring is the largest, brightest, and most massive of
16065-463: The paraboloid by a clever application of Torricelli's principle (i.e., that bodies in a system move only if their centre of gravity descends). He then proves the general theorem that, for a floating body in equilibrium, the distance between its centre of gravity and its submerged portion is at a minimum. Huygens uses this theorem to arrive at original solutions for the stability of floating cones , parallelepipeds , and cylinders , in some cases through
16218-405: The past than at present. The mass estimate alone is not very diagnostic, since high mass rings that formed early in the Solar System's history would have evolved by now to a mass close to that measured. Based on current depletion rates, they may disappear in 300 million years. There are two main theories regarding the origin of Saturn's inner rings. A theory originally proposed by Édouard Roche in
16371-496: The plane for 13.7 years. Dates for north-to-south crossings include 19 November 1995 and 6 May 2025, with south-to-north crossings on 11 August 2009 and 23 January 2039. During the period around an equinox the illumination of most of the rings is greatly reduced, making possible unique observations highlighting features that depart from the ring plane. The dense main rings extend from 7,000 km (4,300 mi) to 80,000 km (50,000 mi) away from Saturn's equator, whose radius
16524-508: The planet Mercury transit over the Sun using Reeve's telescope in London. Streete then debated the published record of Hevelius , a controversy mediated by Henry Oldenburg . Huygens passed to Hevelius a manuscript of Jeremiah Horrocks on the transit of Venus in 1639 , printed for the first time in 1662. In that same year, Sir Robert Moray sent Huygens John Graunt 's life table , and shortly after Huygens and his brother Lodewijk dabbled on life expectancy . Huygens eventually created
16677-487: The planet Saturn from around 1652 with the aim of explaining its appearance. His hypothesis was written up in De corpore saturni, in which he came close to suggesting the planet had a ring. However, Wren was unsure whether the ring was independent of the planet, or physically attached to it. Before Wren's hypothesis was published Christiaan Huygens presented his hypothesis of the rings of Saturn. Immediately Wren recognised this as
16830-399: The planet or, in the case of Saturn's E-ring, the ejecta of cryovolcanic material. Ring systems may form around centaurs when they are tidally disrupted in a close encounter (within 0.4 to 0.8 times the Roche limit ) with a giant planet. For a differentiated body approaching a giant planet at an initial relative velocity of 3−6 km/s with an initial rotational period of 8 hours,
16983-504: The planet, C, B and A, with the Cassini Division, the largest gap, separating Rings B and A. Several fainter rings were discovered more recently. The D Ring is exceedingly faint and closest to the planet. The narrow F Ring is just outside the A Ring. Beyond that are two far fainter rings named G and E. The rings show a tremendous amount of structure on all scales, some related to perturbations by Saturn's moons, but much unexplained. In September 2023, astronomers reported studies suggesting that
17136-481: The planet], inclined to the ecliptic"). He published his ring hypothesis in Systema Saturnium (1659) which also included his discovery of Saturn's moon, Titan , as well as the first clear outline of the dimensions of the Solar System . In 1675, Giovanni Domenico Cassini determined that Saturn's ring was composed of multiple smaller rings with gaps between them; the largest of these gaps was later named
17289-596: The planned resolution; nevertheless, images from the spacecraft provided unprecedented detail of the ring system and revealed the existence of the G ring. Voyager 2 ' s closest approach occurred in August 1981 at a distance of 41,000 km (25,000 mi). Voyager 2 ' s working photopolarimeter allowed it to observe the ring system at higher resolution than Voyager 1 , and to thereby discover many previously unseen ringlets. Cassini spacecraft entered into orbit around Saturn in July 2004. Cassini 's images of
17442-459: The rectification of the ellipse, projectiles, and the vibrating string . Some of Mersenne's concerns at the time, such as the cycloid (he sent Huygens Torricelli 's treatise on the curve), the centre of oscillation , and the gravitational constant , were matters Huygens only took seriously later in the 17th century. Mersenne had also written on musical theory. Huygens preferred meantone temperament ; he innovated in 31 equal temperament (which
17595-414: The ring is blocked, so that when seen from above, the ring is close to transparent. The 30-km wavelength spiral corrugations first seen in the D Ring were observed during Saturn's equinox of 2009 to extend throughout the C Ring (see above). The Colombo Gap lies in the inner C Ring. Within the gap lies the bright but narrow Colombo Ringlet, centered at 77,883 km (48,394 miles) from Saturn's center, which
17748-546: The ring must be composed of numerous small particles, all independently orbiting Saturn. Later, Sofia Kovalevskaya also found that Saturn's rings cannot be liquid ring-shaped bodies. Spectroscopic studies of the rings which were carried out independently in 1895 by James Keeler of the Allegheny Observatory and by Aristarkh Belopolsky of the Pulkovo Observatory showed that Maxwell's analysis
17901-458: The ring system via their gravitational effect during its final set of orbits that passed between the rings and the cloud tops, yielding a value of 1.54 (± 0.49) × 10 kg, or 0.41 ± 0.13 Mimas masses. This is around two-thirds the mass of the Earth's entire Antarctic ice sheet , spread across a surface area 80 times larger than that of Earth. The estimate is close to the value of 0.40 Mimas masses derived from Cassini observations of density waves in
18054-488: The rings and they became invisible. Mystified, Galileo remarked "I do not know what to say in a case so surprising, so unlooked for and so novel." He mused, "Has Saturn swallowed his children?" — referring to the myth of the Titan Saturn devouring his offspring to forestall the prophecy of them overthrowing him. He was further confused when the rings again became visible in 1613. Early astronomers used anagrams as
18207-485: The rings are the most detailed to-date, and are responsible for the discovery of yet more ringlets. The rings are named alphabetically in the order they were discovered: A and B in 1675 by Giovanni Domenico Cassini , C in 1850 by William Cranch Bond and his son George Phillips Bond , D in 1933 by Nikolai P. Barabachov and B. Semejkin , E in 1967 by Walter A. Feibelman , F in 1979 by Pioneer 11 , and G in 1980 by Voyager 1 . The main rings are, working outward from
18360-520: The rings extend significantly out of the nominal ring plane in a few places. This displacement reaches as much as 4 km (2.5 mi) at the border of the Keeler Gap , due to the out-of-plane orbit of Daphnis , the moon that creates the gap. Estimates of the age of Saturn's rings vary widely, depending on the approach used. They have been considered to possibly be very old, dating to the formation of Saturn itself. However, data from Cassini suggest they are much younger, having most likely formed within
18513-421: The rings of Saturn may have resulted from the collision of two moons "a few hundred million years ago". Saturn's axial tilt is 26.7°, meaning that widely varying views of the rings, of which the visible ones occupy its equatorial plane, are obtained from Earth at different times. Earth makes passes through the ring plane every 13 to 15 years, about every half Saturn year, and there are about equal chances of either
18666-419: The rings of Saturn possess their own atmosphere, independent of that of the planet itself. The atmosphere is composed of molecular oxygen gas (O 2 ) produced when ultraviolet light from the Sun interacts with water ice in the rings. Chemical reactions between water molecule fragments and further ultraviolet stimulation create and eject, among other things, O 2 . According to models of this atmosphere, H 2
18819-581: The rings of Saturn was explained as being caused exclusively by the action of gravitational forces. Then images from the Voyager spacecraft showed radial features in the B Ring , known as spokes , which could not be explained in this manner, as their persistence and rotation around the rings was not consistent with gravitational orbital mechanics . The spokes appear dark in backscattered light, and bright in forward-scattered light (see images in Gallery );
18972-494: The rings were likely to have formed early in the Solar System's history, newer data from Cassini suggested they formed relatively late. Although reflection from the rings increases Saturn's brightness , they are not visible from Earth with unaided vision . In 1610, the year after Galileo Galilei turned a telescope to the sky, he became the first person to observe Saturn's rings, though he could not see them well enough to discern their true nature. In 1655, Christiaan Huygens
19125-472: The rings, due to gravitational interactions with the rings and tidal interaction with Saturn, into progressively wider orbits. Within the Roche limit , bodies of rocky material are dense enough to accrete additional material, whereas less-dense bodies of ice are not. Once outside the rings, the newly formed moons could have continued to evolve through random mergers. This process may explain the variation in silicate content of Saturn's moons out to Rhea, as well as
19278-468: The rings. Alternatively, it is proposed that the spokes are very similar to a phenomenon known as lunar horizon glow or dust levitation, and caused by intense electric fields across the terminator of ring particles, not electrical disturbances. The spokes were not observed again until some twenty-five years later, this time by the Cassini space probe. The spokes were not visible when Cassini arrived at Saturn in early 2004. Some scientists speculated that
19431-409: The rings. Its thickness is estimated as 5 to 15 m and its optical depth varies from 0.4 to greater than 5, meaning that >99% of the light passing through some parts of the B Ring is blocked. The B Ring contains a great deal of variation in its density and brightness, nearly all of it unexplained. These are concentric, appearing as narrow ringlets, though the B Ring does not contain any gaps. In places,
19584-502: The same physics that describes the spiral arms of galaxies . Spiral bending waves, also present in the A Ring and also described by the same theory, are vertical corrugations in the ring rather than compression waves. Ring system Ring systems are best known as planetary rings, common components of satellite systems around giant planets such as of Saturn , or circumplanetary disks . But they can also be galactic rings and circumstellar discs , belts of planetoids, such as
19737-457: The southern. In 1980, Voyager 1 made a fly-by of Saturn that showed the F ring to be composed of three narrow rings that appeared to be braided in a complex structure; it is now known that the outer two rings consist of knobs, kinks and lumps that give the illusion of braiding, with the less bright third ring lying inside them. New images of the rings taken around the 11 August 2009 equinox of Saturn by NASA's Cassini spacecraft have shown that
19890-467: The spokes may be a seasonal effect, varying with Saturn's 29.7-year orbit, were supported by their gradual reappearance in the later years of the Cassini mission. In 2009, during equinox, a moonlet embedded in the B ring was discovered from the shadow it cast. It is estimated to be 400 m (1,300 ft) in diameter. The moonlet was given the provisional designation S/2009 S 1 . The Cassini Division
20043-430: The spokes would not be visible again until 2007, based on models attempting to describe their formation. Nevertheless, the Cassini imaging team kept looking for spokes in images of the rings, and they were next seen in images taken on 5 September 2005. The spokes appear to be a seasonal phenomenon, disappearing in the Saturnian midwinter and midsummer and reappearing as Saturn comes closer to equinox . Suggestions that
20196-499: The star UCAC4 248-108672 on June 3, 2013 from seven locations in South America. While watching, they saw two dips in the star's apparent brightness just before and after the occultation. Because this event was observed at multiple locations, the conclusion that the dip in brightness was in fact due to rings is unanimously the leading hypothesis. The observations revealed what is likely a 19-kilometer (12-mile)-wide ring system that
20349-576: The time between then and 2005, observations by Voyager 2 and the Hubble Space Telescope led to a total of 13 distinct rings being identified, most of which are opaque and only a few kilometers wide. They are dark and likely consist of water ice and some radiation-processed organics . The relative lack of dust is due to aerodynamic drag from the extended exosphere - corona of Uranus. The system around Neptune consists of five principal rings that, at their densest, are comparable to
20502-513: The transition occurs at a phase angle near 60 ° . The leading theory regarding the spokes' composition is that they consist of microscopic dust particles suspended away from the main ring by electrostatic repulsion, as they rotate almost synchronously with the magnetosphere of Saturn. The precise mechanism generating the spokes is still unknown. It has been suggested that the electrical disturbances might be caused by either lightning bolts in Saturn's atmosphere or micrometeoroid impacts on
20655-444: The trend towards less silicate content closer to Saturn. Rhea would then be the oldest of the moons formed from the primordial rings, with moons closer to Saturn being progressively younger. The brightness and purity of the water ice in Saturn's rings have also been cited as evidence that the rings are much younger than Saturn, as the infall of meteoric dust would have led to a darkening of the rings. However, new research indicates that
20808-497: The universe this way made the theory of collisions central to physics, as only explanations that involved matter in motion could be truly intelligible. While Huygens was influenced by the Cartesian approach, he was less doctrinaire. He studied elastic collisions in the 1650s but delayed publication for over a decade. Huygens concluded quite early that Descartes's laws for elastic collisions were largely wrong, and he formulated
20961-492: The void against the Cartesian denial of it. Newton's influence on John Locke was mediated by Huygens, who assured Locke that Newton's mathematics was sound, leading to Locke's acceptance of a corpuscular-mechanical physics. The general approach of the mechanical philosophers was to postulate theories of the kind now called "contact action." Huygens adopted this method but not without seeing its limitations, while Leibniz, his student in Paris, later abandoned it. Understanding
21114-504: The work of Viète , Descartes, and Fermat . After two years, starting in March 1647, Huygens continued his studies at the newly founded Orange College , in Breda , where his father was a curator . Constantijn Huygens was closely involved in the new College, which lasted only to 1669; the rector was André Rivet . Christiaan Huygens lived at the home of the jurist Johann Henryk Dauber while attending college, and had mathematics classes with
21267-473: Was a Dutch mathematician , physicist , engineer , astronomer , and inventor who is regarded as a key figure in the Scientific Revolution . In physics, Huygens made seminal contributions to optics and mechanics , while as an astronomer he studied the rings of Saturn and discovered its largest moon, Titan . As an engineer and inventor, he improved the design of telescopes and invented
21420-455: Was a diplomat and advisor to the House of Orange , in addition to being a poet and a musician. He corresponded widely with intellectuals across Europe; his friends included Galileo Galilei , Marin Mersenne , and René Descartes . Christiaan was educated at home until the age of sixteen, and from a young age liked to play with miniatures of mills and other machines. From his father he received
21573-552: Was bittersweet and somewhat puzzling since it became clear that Fermat had dropped out of the research mainstream, and his priority claims could probably not be made good in some cases. Besides, Huygens was looking by then to apply mathematics to physics, while Fermat's concerns ran to purer topics. Like some of his contemporaries, Huygens was often slow to commit his results and discoveries to print, preferring to disseminate his work through letters instead. In his early days, his mentor Frans van Schooten provided technical feedback and
21726-474: Was born on 14 April 1629 in The Hague , into a rich and influential Dutch family, the second son of Constantijn Huygens . Christiaan was named after his paternal grandfather. His mother, Suzanna van Baerle , died shortly after giving birth to Huygens's sister. The couple had five children: Constantijn (1628), Christiaan (1629), Lodewijk (1631), Philips (1632) and Suzanna (1637). Constantijn Huygens
21879-482: Was cautious for the sake of his reputation. Between 1651 and 1657, Huygens published a number of works that showed his talent for mathematics and his mastery of classical and analytical geometry , increasing his reach and reputation among mathematicians. Around the same time, Huygens began to question Descartes's laws of collision , which were largely wrong, deriving the correct laws algebraically and later by way of geometry. He showed that, for any system of bodies,
22032-541: Was correct. Four robotic spacecraft have observed Saturn's rings from the vicinity of the planet. Pioneer 11 ' s closest approach to Saturn occurred in September 1979 at a distance of 20,900 km (13,000 mi). Pioneer 11 was responsible for the discovery of the F ring. Voyager 1 ' s closest approach occurred in November 1980 at a distance of 64,200 km (39,900 mi). A failed photopolarimeter prevented Voyager 1 from observing Saturn's rings at
22185-573: Was covered fully for the first time by Newton in Book II of the Principia Mathematica (1687). In 1678 Leibniz picked out of Huygens's work on collisions the idea of conservation law that Huygens had left implicit. In 1657, inspired by earlier research into pendulums as regulating mechanisms, Huygens invented the pendulum clock, which was a breakthrough in timekeeping and became the most accurate timekeeper for almost 300 years until
22338-481: Was detected from Earth by the Hubble Space Telescope. Saturn shows complex patterns in its brightness. Most of the variability is due to the changing aspect of the rings, and this goes through two cycles every orbit. However, superimposed on this is variability due to the eccentricity of the planet's orbit that causes the planet to display brighter oppositions in the northern hemisphere than it does in
22491-405: Was determined to very likely be an expanding debris cloud from a collision of asteroids rather than a planet. Similarly, Proxima Centauri c has been observed to be far brighter than expected for its low mass of 7 Earth masses, which may be attributed to a ring system of about 5 R J . A 56-day-long sequence of dimming events in the star V1400 Centauri observed in 2007 was interpreted as
22644-408: Was directly related to the area of that segment. He was then able to show the relationships between triangles inscribed in conic sections and the centre of gravity for those sections. By generalizing these theorems to cover all conic sections, Huygens extended classical methods to generate new results. Quadrature was a live issue in the 1650s and, through Mylon, Huygens intervened in the discussion of
22797-507: Was not itself a new idea but known to Francisco de Salinas ), using logarithms to investigate it further and show its close relation to the meantone system. In 1654, Huygens returned to his father's house in The Hague and was able to devote himself entirely to research. The family had another house, not far away at Hofwijck , and he spent time there during the summer. Despite being very active, his scholarly life did not allow him to escape bouts of depression. Subsequently, Huygens developed
22950-403: Was surrounded by a ring detached from the planet, and famously published the letter string " aaaaaaacccccdeeeeeghiiiiiiillllmmnnnnnnnnnooooppqrrstttttuuuuu ". Three years later, he revealed it to mean Annulo cingitur, tenui, plano, nusquam coherente, ad eclipticam inclinato ("[Saturn] is surrounded by a thin, flat, ring, nowhere touching [the body of
23103-542: Was that of Archimedes, though he made use of Descartes's analytic geometry and Fermat's infinitesimal techniques more extensively in his private notebooks. Huygens's first publication was Theoremata de Quadratura Hyperboles, Ellipsis et Circuli ( Theorems on the quadrature of the hyperbola, ellipse, and circle ), published by the Elzeviers in Leiden in 1651. The first part of the work contained theorems for computing
23256-609: Was the first person to describe them as a disk surrounding Saturn. The concept that Saturn's rings are made up of a series of tiny ringlets can be traced to Pierre-Simon Laplace , although true gaps are few – it is more correct to think of the rings as an annular disk with concentric local maxima and minima in density and brightness. On the scale of the clumps within the rings there is much empty space. The rings have numerous gaps where particle density drops sharply: two opened by known moons embedded within them, and many others at locations of known destabilizing orbital resonances with
23409-401: Was written around 1650 and was made up of three books. Although he sent the completed work to Frans van Schooten for feedback, in the end Huygens chose not to publish it, and at one point suggested it be burned. Some of the results found here were not rediscovered until the eighteenth and nineteenth centuries. Huygens first re-derives Archimedes's solutions for the stability of the sphere and
#251748