vania-janet/multiturn-rag-retrieval-data huggingface dataset:
Jupiter
Before the discoveries of the Voyager missions , Jupiter 's moons were arranged neatly into four groups of four , based on commonality of their orbital elements . Since then , the large number of new small outer moons has complicated this picture . There are now thought to be six main groups , although some are more distinct than others .
Maya calendar
A lunar series generally is written as five glyphs that provide information about the current lunation , the number of the lunation in a series of six , the current ruling lunar deity and the length of the current lunation . Moon
Lunar phase
Each of the 4 lunar phases lasts approximately 7 days ( ~ 7.4 days ) , but varies slightly due to lunar apogee and perigee .
Desert
The shape of the dune depends on the characteristics of the prevailing wind . Barchan dunes are produced by strong winds blowing across a level surface , and are crescent - shaped with the concave side away from the wind . When there are two directions from which winds regularly blow , a series of long , linear dunes known as seif dunes may form . These also occur parallel to a strong wind that blows in one general direction . Transverse dunes run at a right angle to the prevailing wind direction . Star dunes are formed by variable winds , and have several ridges and slip faces radiating from a central point . They tend to grow vertically ; they can reach a height of 500 m ( 1,600 ft ) , making them the tallest type of dune . Rounded mounds of sand without a slip face are the rare dome dunes , found on the upwind edges of sand seas . Windswept
Mars
After the formation of the planets , all were subjected to the so - called `` Late Heavy Bombardment '' . About 60 % of the surface of Mars shows a record of impacts from that era , whereas much of the remaining surface is probably underlain by immense impact basins caused by those events . There is evidence of an enormous impact basin in the northern hemisphere of Mars , spanning 10,600 by 8,500 km ( 6,600 by 5,300 mi ) , or roughly four times the size of the Moon 's South Pole -- Aitken basin , the largest impact basin yet discovered . This theory suggests that Mars was struck by a Pluto - sized body about four billion years ago . The event , thought to be the cause of the Martian hemispheric dichotomy , created the smooth Borealis basin that covers 40 % of the planet . Artist
Mars
Along crater and canyon walls , there are thousands of features that appear similar to terrestrial gullies . The gullies tend to be in the highlands of the southern hemisphere and to face the Equator ; all are poleward of 30 ° latitude . A number of authors have suggested that their formation process involves liquid water , probably from melting ice , although others have argued for formation mechanisms involving carbon dioxide frost or the movement of dry dust . No partially degraded gullies have formed by weathering and no superimposed impact craters have been observed , indicating that these are young features , possibly still active . Other geological features , such as deltas and alluvial fans preserved in craters , are further evidence for warmer , wetter conditions at an interval or intervals in earlier Mars history . Such conditions necessarily require the widespread presence of crater lakes across a large proportion of the surface , for which there is independent mineralogical , sedimentological and geomorphological evidence . Composition
Earth
The Blue Marble photograph of Earth , taken during the Apollo 17 lunar mission in 1972 Orbital characteristics Epoch J2000 Aphelion 152 100 000 km ( 94 500 000 mi ; 1.017 AU ) Perihelion 147 095 000 km ( 91 401 000 mi ; 0.983 27 AU ) Semi-major axis 149 598 023 km ( 92 955 902 mi ; 1.000 001 02 AU ) Eccentricity 6998167086000000000 ♠ 0.016 7086 Orbital period 365.256 363 004 d ( 1.000 017 420 96 yr ) Average orbital speed 29.78 km / s ( 107 200 km / h ; 66 600 mph ) Mean anomaly 7000625904740362451 ♠ 358.617 ° Inclination 6999124878307980194 ♠ 7.155 ° to the Sun 's equator ; 6998275533383683093 ♠ 1.578 69 ° to invariable plane ; 6993872664625997166 ♠ 0.000 05 ° to J2000 ecliptic Longitude of ascending node 3000803464756118225 ♠ − 11.260 64 ° to J2000 ecliptic Argument of perihelion 7000199330266505796 ♠ 114.207 83 ° Satellites 1 natural satellite : the Moon 5 quasi-satellites > 1 700 operational artificial satellites > 16 000 space debris Physical characteristics Mean radius 6371.0 km ( 3958.8 mi ) Equatorial radius 6378.1 km ( 3963.2 mi ) Polar radius 6356.8 km ( 3949.9 mi ) Flattening 6997335280000000000 ♠ 0.003 3528 1 /
Jupiter
A basic sub-division is a grouping of the eight inner regular moons , which have nearly circular orbits near the plane of Jupiter 's equator and are thought to have formed with Jupiter . The remainder of the moons consist of an unknown number of small irregular moons with elliptical and inclined orbits , which are thought to be captured asteroids or fragments of captured asteroids . Irregular moons that belong to a group share similar orbital elements and thus may have a common origin , perhaps as a larger moon or captured body that broke up .
Wikipedia:Citing sources
The Sun is pretty big ( Miller 2005 , p. 1 ) , but the Moon is not so big ( Brown 2006 , p. 2 ) . The Sun is also quite hot ( Miller 2005 , p. 3 ) . References
Earth
A subject of research is the formation of the Moon , some 4.53 Bya . A leading hypothesis is that it was formed by accretion from material loosed from Earth after a Mars - sized object , named Theia , hit Earth . In this view , the mass of Theia was approximately 10 percent of Earth , it hit Earth with a glancing blow and some of its mass merged with Earth . Between approximately 4.1 and 7000380000000000000 ♠ 3.8 Bya , numerous asteroid impacts during the Late Heavy Bombardment caused significant changes to the greater surface environment of the Moon and , by inference , to that of Earth .
Jupiter
Jupiter has a faint planetary ring system composed of three main segments : an inner torus of particles known as the halo , a relatively bright main ring , and an outer gossamer ring . These rings appear to be made of dust , rather than ice as with Saturn 's rings . The main ring is probably made of material ejected from the satellites Adrastea and Metis . Material that would normally fall back to the moon is pulled into Jupiter because of its strong gravitational influence . The orbit of the material veers towards Jupiter and new material is added by additional impacts . In a similar way , the moons Thebe and Amalthea probably produce the two distinct components of the dusty gossamer ring . There is also evidence of a rocky ring strung along Amalthea 's orbit which may consist of collisional debris from that moon .
Lunar distance (astronomy)
For increased accuracy , certain systematic errors must be accounted for , such as adjusting the measured angle to account for refraction and distortion of light through the atmosphere . Lunar
Lunar distance (astronomy)
The distance to the Moon can be measured to an accuracy of 6997200000000000000 ♠ 2 mm over a 1 - hour sampling period , which results in an overall uncertainty of 6998200000000000000 ♠ 2 -- 3 cm for the average distance . However , due to its elliptical orbit with varying eccentricity , the instantaneous distance varies with monthly periodicity . Furthermore , the distance is perturbed by the gravitational effects of various astronomical bodies - most significantly the Sun and less so by Jupiter . Other forces responsible for minuscule perturbations are other planets in the solar system , asteroids , tidal forces , and relativistic effects . The effect of radiation pressure from the sun contributes an amount of ± 6997360000000000000 ♠ 3.6 mm to the lunar distance .
Venus
Venus has no natural satellites . It has several trojan asteroids : the quasi-satellite 2002 VE 68 and two other temporary trojans , 2001 CK and 2012 XE 133 . In the 17th century , Giovanni Cassini reported a moon orbiting Venus , which was named Neith and numerous sightings were reported over the following 7009631152000000000 ♠ 200 years , but most were determined to be stars in the vicinity . Alex Alemi 's and David Stevenson 's 2006 study of models of the early Solar System at the California Institute of Technology shows Venus likely had at least one moon created by a huge impact event billions of years ago . About 10 million years later , according to the study , another impact reversed the planet 's spin direction and caused the Venusian moon gradually to spiral inward until it collided with Venus . If later impacts created moons , these were removed in the same way . An alternative explanation for the lack of satellites is the effect of strong solar tides , which can destabilize large satellites orbiting the inner terrestrial planets .
Moon landing
From that vantage point , scientists could make direct measurements of the magnetosphere over a period of many months while engineers perfected new methods to routinely track and communicate with spacecraft over such large distances . Such practice was deemed vital to be assured of capturing high - bandwidth television transmissions from the Moon during a one - shot fifteen - minute time window in subsequent Block II and Block III lunar descents . Both Block I missions suffered failures of the new Agena upper stage and never left low Earth parking orbit after launch ; both burned up upon reentry after only a few days .
Moon landing
The Soviets succeeded in making the first crash landing on the Moon in 1959 . Crash landings may occur because of malfunctions in a spacecraft , or they can be deliberately arranged for vehicles which do not have an onboard landing rocket . There have been many such moon crashes , often with their flight path controlled to impact at precise locations on the lunar surface . For example , during the Apollo program the S - IVB third stage of the Saturn V moon rocket as well as the spent ascent stage of the lunar module were deliberately crashed on the Moon several times to provide impacts registering as a moonquake on seismometers that had been left on the lunar surface . Such crashes were instrumental in mapping the internal structure of the Moon .
Kuiper belt
Although to date most KBOs still appear spectrally featureless due to their faintness , there have been a number of successes in determining their composition . In 1996 , Robert H. Brown et al. acquired spectroscopic data on the KBO 1993 SC , which revealed that its surface composition is markedly similar to that of Pluto , as well as Neptune 's moon Triton , with large amounts of methane ice . For the smaller objects , only colors and in some cases the albedos have been determined . These objects largely fall into two classes : gray with low albedos , or very red with higher albedos . The difference in colors and albedos is hypothesized to be due to the retention or the loss of hydrogen sulfide ( H S ) on the surface of these objects , with the surfaces of those that formed far enough from the Sun to retain H S being reddened due to irradiation .
Sundial
Unlike the fixed stars , the Sun changes its position on the celestial sphere , being - on north hemisphere - at a positive declination in spring and summer , and at a negative declination in autumn and winter , and having exactly zero declination ( i.e. , being on the celestial equator ) at the equinoxes . The Sun 's celestial longitude also varies , changing by one complete revolution per year . The path of the Sun on the celestial sphere is called the ecliptic . The ecliptic passes through the twelve constellations of the zodiac in the course of a year . Sundial
Earth
The Moon and Earth orbit a common barycenter every 27.32 days relative to the background stars . When combined with the Earth -- Moon system 's common orbit around the Sun , the period of the synodic month , from new moon to new moon , is 29.53 days . Viewed from the celestial north pole , the motion of Earth , the Moon , and their axial rotations are all counterclockwise . Viewed from a vantage point above the north poles of both the Sun and Earth , Earth orbits in a counterclockwise direction about the Sun . The orbital and axial planes are not precisely aligned : Earth 's axis is tilted some 23.44 degrees from the perpendicular to the Earth -- Sun plane ( the ecliptic ) , and the Earth -- Moon plane is tilted up to ± 5.1 degrees against the Earth -- Sun plane . Without this tilt , there would be an eclipse every two weeks , alternating between lunar eclipses and solar eclipses .
Meander
Various mathematical formulae relate the variables of the meander geometry . As it turns out some numerical parameters can be established , which appear in the formulae . The waveform depends ultimately on the characteristics of the flow but the parameters are independent of it and apparently are caused by geologic factors . In general the meander length is 10 -- 14 times , with an average 11 times , the fullbank channel width and 3 to 5 times , with an average of 4.7 times , the radius of curvature at the apex . This radius is 2 -- 3 times the channel width . Meander
Lunar phase
The Earth subtends an angle of about two degrees , when seen from the Moon . This means that an observer on Earth who sees the Moon when it is close to the eastern horizon sees it from an angle that is about two degrees different from the line of sight of an observer who sees the Moon on the western horizon . The Moon moves about 12 degrees around its orbit per day , so , if these observers were stationary , they would see the phases of the Moon at times that differ by about one - sixth of a day , or four hours . But in reality the observers are on the surface of the rotating Earth , so someone who sees the Moon on the eastern horizon at one moment sees it on the western horizon about 12 hours later . This adds an oscillation to the apparent progression of the lunar phases . They appear to occur more slowly when the Moon is high in the sky than when it is below the horizon . The Moon appears to move jerkily , and the phases do the same . The amplitude of this oscillation is never more than about four hours , which is a small fraction of a month . It does not have any obvious effect on the appearance of the Moon . However , it does affect accurate calculations of the times of lunar phases .
Kuiper belt
Modern computer simulations show the Kuiper belt to have been strongly influenced by Jupiter and Neptune , and also suggest that neither Uranus nor Neptune could have formed in their present positions , because too little primordial matter existed at that range to produce objects of such high mass . Instead , these planets are estimated to have formed closer to Jupiter . Scattering of planetesimals early in the Solar System 's history would have led to migration of the orbits of the giant planets : Saturn , Uranus , and Neptune drifted outwards , whereas Jupiter drifted inwards . Eventually , the orbits shifted to the point where Jupiter and Saturn reached an exact 1 : 2 resonance ; Jupiter orbited the Sun twice for every one Saturn orbit . The gravitational repercussions of such a resonance ultimately destabilized the orbits of Uranus and Neptune , causing them to be scattered outward onto high - eccentricity orbits that crossed the primordial planetesimal disc . While Neptune 's orbit was highly eccentric , its mean - motion resonances overlapped and the orbits of the planetesimals evolved chaotically , allowing planetesimals to wander outward as far as Neptune 's 1 : 2 resonance to form a dynamically cold belt of low - inclination objects . Later , after its eccentricity decreased , Neptune 's orbit expanded outward toward its current position . Many planetesimals were captured into and remain in resonances during this migration , others evolved onto higher - inclination and lower - eccentricity orbits and escaped from the resonances onto stable orbits . Many more planetesimals were scattered inward , with small fractions being captured as Jupiter trojans , as irregular satellites orbiting the giant planets , and as outer belt asteroids . The remainder were scattered outward again by Jupiter and in most cases ejected from the Solar System reducing the primordial Kuiper belt population by 99 % or more .
Sundial
The diptych consisted of two small flat faces , joined by a hinge . Diptychs usually folded into little flat boxes suitable for a pocket . The gnomon was a string between the two faces . When the string was tight , the two faces formed both a vertical and horizontal sundial . These were made of white ivory , inlaid with black lacquer markings . The gnomons were black braided silk , linen or hemp string . With a knot or bead on the string as a nodus , and the correct markings , a diptych ( really any sundial large enough ) can keep a calendar well - enough to plant crops . A common error describes the diptych dial as self - aligning . This is not correct for diptych dials consisting of a horizontal and vertical dial using a string gnomon between faces , no matter the orientation of the dial faces . Since the string gnomon is continuous , the shadows must meet at the hinge ; hence , any orientation of the dial will show the same time on both dials .
Moon landing
Following the unsuccessful Atlas - Able Pioneer probes , NASA 's Jet Propulsion Laboratory embarked upon an unmanned spacecraft development program whose modular design could be used to support both lunar and interplanetary exploration missions . The interplanetary versions were known as Mariners ; lunar versions were Rangers . JPL envisioned three versions of the Ranger lunar probes : Block I prototypes , which would carry various radiation detectors in test flights to a very high Earth orbit that came nowhere near the Moon ; Block II , which would try to accomplish the first Moon landing by hard landing a seismometer package ; and Block III , which would crash onto the lunar surface without any braking rockets while taking very high resolution wide - area photographs of the Moon during their descent .
Earth
The shape of Earth is approximately oblate spheroidal . Due to rotation , the Earth is flattened at the poles and bulging around the equator . The diameter of the Earth at the equator is 43 kilometres ( 27 mi ) larger than the pole - to - pole diameter . Thus the point on the surface farthest from Earth 's center of mass is the summit of the equatorial Chimborazo volcano in Ecuador . The average diameter of the reference spheroid is 12,742 kilometres ( 7,918 mi ) . Local topography deviates from this idealized spheroid , although on a global scale these deviations are small compared to Earth 's radius : The maximum deviation of only 0.17 % is at the Mariana Trench ( 10,911 metres ( 35,797 ft ) below local sea level ) , whereas Mount Everest ( 8,848 metres ( 29,029 ft ) above local sea level ) represents a deviation of 0.14 % .
Exploration of Mars
Magnetometer readings showed that the planet 's magnetic field is not globally generated in the planet 's core , but is localized in particular areas of the crust . New temperature data and closeup images of the Martian moon Phobos showed that its surface is composed of powdery material at least 1 metre ( 3 feet ) thick , caused by millions of years of meteoroid impacts . Data from the spacecraft 's laser altimeter gave scientists their first 3 - D views of Mars ' north polar ice cap . On November 5 , 2006 MGS lost contact with Earth . NASA ended efforts to restore communication on January 28 , 2007 . Mars
Apollo
The earth deity had power over the ghostly world , and it is believed that she was the deity behind the oracle . The older tales mentioned two dragons who were perhaps intentionally conflated . A female dragon named Delphyne ( δελφύς , `` womb '' ) , and a male serpent Typhon ( τύφειν , `` to smoke '' ) , the adversary of Zeus in the Titanomachy , who the narrators confused with Python . Python was the good daemon ( ἀγαθὸς δαίμων ) of the temple as it appears in Minoan religion , but she was represented as a dragon , as often happens in Northern European folklore as well as in the East .
Reuleaux triangle
In the classical presentation of a three - set Venn diagram as three overlapping circles , the central region ( representing elements belonging to all three sets ) takes the shape of a Reuleaux triangle . The same three circles form one of the standard drawings of the Borromean rings , three mutually linked rings that can not , however , be realized as geometric circles . Parts of these same circles are used to form the triquetra , a figure of three overlapping semicircles ( each two of which form a vesica piscis symbol ) that again has a Reuleaux triangle at its center ; just as the three circles of the Venn diagram may be interlaced to form the Borromean rings , the three circular arcs of the triquetra may be interlaced to form a trefoil knot .
Magnetosphere of Jupiter
All Galilean moons have thin atmospheres with surface pressures in the range 0.01 -- 1 nbar , which in turn support substantial ionospheres with electron densities in the range of 1,000 -- 10,000 cm . The co-rotational flow of cold magnetospheric plasma is partially diverted around them by the currents induced in their ionospheres , creating wedge - shaped structures known as Alfvén wings . The interaction of the large moons with the co-rotational flow is similar to the interaction of the solar wind with the non-magnetized planets like Venus , although the co-rotational speed is usually subsonic ( the speeds vary from 74 to 328 km / s ) , which prevents the formation of a bow shock . The pressure from the co-rotating plasma continuously strips gases from the moons ' atmospheres ( especially from that of Io ) , and some of these atoms are ionized and brought into co-rotation . This process creates gas and plasma tori in the vicinity of moons ' orbits with the Ionian torus being the most prominent . In effect , the Galilean moons ( mainly Io ) serve as the principal plasma sources in Jupiter 's inner and middle magnetosphere . Meanwhile , the energetic particles are largely unaffected by the Alfvén wings and have free access to the moons ' surfaces ( except Ganymede 's ) . Plasma
Moon landing
Three different designs of Pioneer lunar probes were flown on three different modified ICBMs . Those flown on the Thor booster modified with an Able upper stage carried an infrared image scanning television system with a resolution of 1 milliradian to study the Moon 's surface , an ionization chamber to measure radiation in space , a diaphragm / microphone assembly to detect micrometeorites , a magnetometer , and temperature - variable resistors to monitor spacecraft internal thermal conditions . The first , a mission managed by the United States Air Force , exploded during launch ; all subsequent Pioneer lunar flights had NASA as the lead management organization . The next two returned to Earth and burned up upon reentry into the atmosphere after achieved maximum altitudes of around 110,000 kilometres ( 68,000 mi ) and 1,450 kilometres ( 900 mi ) , far short of the roughly 400,000 kilometres ( 250,000 mi ) required to reach the vicinity of the Moon .
Sundial
The sundials described above have gnomons that are aligned with the Earth 's rotational axis and cast their shadow onto a plane . If the plane is neither vertical nor horizontal nor equatorial , the sundial is said to be reclining or inclining . Such a sundial might be located on a South - facing roof , for example . The hour - lines for such a sundial can be calculated by slightly correcting the horizontal formula above