Query: "The solar system oscillates with a 60-year cycle due to the Jupiter/Saturn three-synodic cycle and to a Jupiter/Saturn beat tidal cycle...

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Tibetan calendar <=SEP=> The Tibetan calendar is a lunisolar calendar , that is , the Tibetan year is composed of either 12 or 13 lunar months , each beginning and ending with a new moon . A thirteenth month is added every two or three years , so that an average Tibetan year is equal to the solar year .   The Tibetan New Year celebration is Losar . According to almanacs the year starts with the third Hor month . There were many different traditions in Tibet to fix the beginning of the year . The dates of Mongolian calendar are all the same with it .

Year <=SEP=> A year is the orbital period of the Earth moving in its orbit around the Sun . Due to the Earth 's axial tilt , the course of a year sees the passing of the seasons , marked by changes in weather , the hours of daylight , and , consequently , vegetation and soil fertility . In temperate and subpolar regions around the globe , four seasons are generally recognized : spring , summer , autumn and winter . In tropical and subtropical regions several geographical sectors do not present defined seasons ; but in the seasonal tropics , the annual wet and dry seasons are recognized and tracked .   A calendar year is an approximation of the number of days of the Earth 's orbital period as counted in a given calendar . The Gregorian , or modern , calendar , presents its calendar year to be either a common year of 365 days or a leap year of 366 days , as do the Julian calendars ; see below . For the Gregorian calendar the average length of the calendar year ( the mean year ) across the complete leap cycle of 400 years is 365.2425 days . The ISO standard ISO 80000-3 , Annex C , supports the symbol `` a '' ( for Latin annus ) to represent a year of either 365 or 366 days . In English , the abbreviations `` y '' and `` yr '' are commonly used .   In astronomy , the Julian year is a unit of time ; it is defined as 365.25 days of exactly seconds ( SI base unit ) , totalling exactly seconds in the Julian astronomical year .   The word `` year '' is also used for periods loosely associated with , but not identical to , the calendar or astronomical year , such as the seasonal year , the fiscal year , the academic year , etc. . Similarly , `` year '' can mean the orbital period of any planet : for example , a Martian year or a Venusian year are examples of the time a planet takes to transit one complete orbit . The term can also be used in reference to any long period or cycle , such as the Great Year .

Orbital resonance <=SEP=> In celestial mechanics , an orbital resonance occurs when orbiting bodies exert a regular , periodic gravitational influence on each other , usually because their orbital periods are related by a ratio of small integers . Most commonly this relationship is found for a pair of objects . The physics principle behind orbital resonance is similar in concept to pushing a child on a swing , where the orbit and the swing both have a natural frequency , and the other body doing the `` pushing '' will act in periodic repetition to have a cumulative effect on the motion . Orbital resonances greatly enhance the mutual gravitational influence of the bodies , i.e. , their ability to alter or constrain each other 's orbits . In most cases , this results in an unstable interaction , in which the bodies exchange momentum and shift orbits until the resonance no longer exists . Under some circumstances , a resonant system can be stable and self-correcting , so that the bodies remain in resonance . Examples are the 1:2:4 resonance of Jupiter 's moons Ganymede , Europa and Io , and the 2:3 resonance between Pluto and Neptune . Unstable resonances with Saturn 's inner moons give rise to gaps in the rings of Saturn . The special case of 1:1 resonance ( between bodies with similar orbital radii ) causes large Solar System bodies to eject most other bodies sharing their orbits ; this is part of the much more extensive process of clearing the neighbourhood , an effect that is used in the current definition of a planet .   A binary resonance ratio in this article should be interpreted as the completed in the same time interval , rather than as the , which would be the inverse ratio . Thus the 2:3 ratio above means Pluto completes two orbits in the time it takes Neptune to complete three . In the case of resonance relationships between three or more bodies , either type of ratio may be used ( in such cases the smallest whole-integer ratio sequences are not necessarily reversals of each other ) and the type of ratio will be specified .

Jupiter trojan <=SEP=> The Jupiter trojans , commonly called Trojan asteroids or just Trojans , are a large group of asteroids that share the orbit of the planet Jupiter around the Sun . Relative to Jupiter , each Trojan librates around one of Jupiter 's two stable Lagrangian points , , lying 60 ° ahead of the planet in its orbit , and , 60 ° behind . Jupiter trojans are distributed in two elongated , curved regions around these Lagrangian points with an average semi-major axis of about 5.2 AU .   The first Jupiter trojan discovered , 588 Achilles , was spotted in 1906 by German astronomer Max Wolf . A total of 6,178 Jupiter trojans have been found . By convention they are each named after a mythological figure from the Trojan War , hence the name `` Trojan '' . The total number of Jupiter trojans larger than 1 km in diameter is believed to be about , approximately equal to the number of asteroids larger than 1 km in the asteroid belt . Like main-belt asteroids , Jupiter trojans form families .   Jupiter trojans are dark bodies with reddish , featureless spectra . No firm evidence of the presence of water , or any other specific compound on their surface has been obtained , but it is thought that they are coated in tholins , organic polymers formed by the Sun 's radiation . The Jupiter trojans ' densities ( as measured by studying binaries or rotational lightcurves ) vary from 0.8 to 2.5 g · cm − 3 . Jupiter trojans are thought to have been captured into their orbits during the early stages of the Solar System 's formation or slightly later , during the migration of giant planets .   The term `` trojan '' has come to be used more generally to refer to other small Solar System bodies with similar relationships to larger bodies : for example , there are both Mars trojans and Neptune trojans , and Saturn has trojan moons . NASA has announced the discovery of an Earth trojan . The term `` Trojan asteroid '' is normally understood to specifically mean the Jupiter trojans because the first Trojans were discovered near Jupiter 's orbit and Jupiter currently has by far the most known Trojans .

Saturn <=SEP=> Saturn is the sixth planet from the Sun and the second-largest in the Solar System , after Jupiter . It is a gas giant with an average radius about nine times that of Earth . Although it has only one-eighth the average density of Earth , with its larger volume Saturn is just over 95 times more massive . Saturn is named after the Roman god of agriculture ; its astronomical symbol represents the god 's sickle .   Saturn 's interior is probably composed of a core of iron -- nickel and rock ( silicon and oxygen compounds ) . This core is surrounded by a deep layer of metallic hydrogen , an intermediate layer of liquid hydrogen and liquid helium , and finally outside the Frenkel line a gaseous outer layer . Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere . Electrical current within the metallic hydrogen layer is thought to give rise to Saturn 's planetary magnetic field , which is weaker than Earth 's , but has a magnetic moment 580 times that of Earth due to Saturn 's larger size . Saturn 's magnetic field strength is around one-twentieth of Jupiter 's . The outer atmosphere is generally bland and lacking in contrast , although long-lived features can appear . Wind speeds on Saturn can reach 1800 km/h , higher than on Jupiter , but not as high as those on Neptune .   Saturn has a prominent ring system that consists of nine continuous main rings and three discontinuous arcs and that is composed mostly of ice particles with a smaller amount of rocky debris and dust . Sixty-two moons are known to orbit Saturn , of which fifty-three are officially named . This does not include the hundreds of moonlets comprising the rings . Titan , Saturn 's largest moon , and the second-largest in the Solar System , is larger than the planet Mercury , although less massive , and is the only moon in the Solar System to have a substantial atmosphere .