vania-janet/multiturn-rag-retrieval-data huggingface dataset:
Jupiter
Both Giovanni Borelli and Cassini made careful tables of the motions of Jupiter 's moons , allowing predictions of the times when the moons would pass before or behind the planet . By the 1670s , it was observed that when Jupiter was on the opposite side of the Sun from Earth , these events would occur about 17 minutes later than expected . Ole Rømer deduced that light does not travel instantaneously ( a conclusion that Cassini had earlier rejected ) , and this timing discrepancy was used to estimate the speed of light .
Communications satellite
A MEO is a satellite in orbit somewhere between 2,000 and 35,786 kilometres ( 1,243 and 22,236 mi ) above the earth 's surface . MEO satellites are similar to LEO satellites in functionality . MEO satellites are visible for much longer periods of time than LEO satellites , usually between 2 and 8 hours . MEO satellites have a larger coverage area than LEO satellites . A MEO satellite 's longer duration of visibility and wider footprint means fewer satellites are needed in a MEO network than a LEO network . One disadvantage is that a MEO satellite 's distance gives it a longer time delay and weaker signal than a LEO satellite , although these limitations are not as severe as those of a GEO satellite .
Moon landing
In 1970 and 1973 two Lunokhod ( `` Moonwalker '' ) robotic lunar rovers were delivered to the Moon , where they successfully operated for 10 and 4 months respectively , covering 10.5 km ( Lunokhod 1 ) and 37 km ( Lunokhod 2 ) . These rover missions were in operation concurrently with the Zond and Luna series of Moon flyby , orbiter and landing missions .
Communications satellite
A low Earth orbit ( LEO ) typically is a circular orbit about 160 to 2,000 kilometres ( 99 to 1,243 mi ) above the earth 's surface and , correspondingly , a period ( time to revolve around the earth ) of about 90 minutes .
Mars
Mars 's average distance from the Sun is roughly 230 million kilometres ( 143,000,000 mi ) , and its orbital period is 687 ( Earth ) days . The solar day ( or sol ) on Mars is only slightly longer than an Earth day : 24 hours , 39 minutes , and 35.244 seconds . A Martian year is equal to 1.8809 Earth years , or 1 year , 320 days , and 18.2 hours .
Moon landing
By this time flights of the third generation U.S. Apollo spacecraft had begun . Far more capable than the Zond , the Apollo spacecraft had the necessary rocket power to slip into and out of lunar orbit and to make course adjustments required for a safe reentry during the return to Earth . The Apollo 8 mission carried out the first manned trip to the Moon on 24 December 1968 , certifying the Saturn V booster for manned use and flying not a circumlunar loop but instead a full ten orbits around the Moon before returning safely to Earth . Apollo 10 then performed a full dress rehearsal of a manned Moon landing in May 1969 . This mission orbited within 47,400 feet ( 14.4 km ) altitude above the lunar surface , performing necessary low - altitude mapping of trajectory - altering mascons using a factory prototype lunar module that was too overweight to allow a successful landing . With the failure of the unmanned Soviet sample return Moon landing attempt Luna 15 in July 1969 , the stage was set for Apollo 11 .
Moon landing
The Luna 9 spacecraft , launched by the Soviet Union , performed the first successful soft Moon landing on 3 February . Airbags protected its 99 kilograms ( 218 lb ) ejectable capsule which survived an impact speed of over 15 metres per second ( 54 km / h ) . Luna 13 duplicated this feat with a similar Moon landing on 24 December 1966 . Both returned panoramic photographs that were the first views from the lunar surface .
Earth
Earth 's atmosphere has no definite boundary , slowly becoming thinner and fading into outer space . Three - quarters of the atmosphere 's mass is contained within the first 11 km ( 6.8 mi ) of the surface . This lowest layer is called the troposphere . Energy from the Sun heats this layer , and the surface below , causing expansion of the air . This lower - density air then rises and is replaced by cooler , higher - density air . The result is atmospheric circulation that drives the weather and climate through redistribution of thermal energy .
Earth's location in the Universe
Since there is believed to be no `` center '' or `` edge '' of the Universe , there is no particular reference point with which to plot the overall location of the Earth in the universe . Because the observable universe is defined as that region of the Universe visible to terrestrial observers , Earth is , by definition , the center of Earth 's observable universe . Reference can be made to the Earth 's position with respect to specific structures , which exist at various scales . It is still undetermined whether the Universe is infinite . There have been numerous hypotheses that our universe may be only one such example within a higher multiverse ; however , no direct evidence of any sort of multiverse has ever been observed , and some have argued that the hypothesis is not falsifiable . A
Sundial
There is a simple verification of hyperbolic declination lines on a sundial : the distance from the origin to the equinox line should be equal to harmonic mean of distances from the origin to summer and winter solstice lines .
Earth's orbit
The following diagram shows the relation between the line of solstice and the line of apsides of Earth 's elliptical orbit . The orbital ellipse goes through each of the six Earth images , which are sequentially the perihelion ( periapsis -- nearest point to the Sun ) on anywhere from January 2 to January 5 , the point of March equinox on March 19 , 20 , or 21 , the point of June solstice on June 20 , 21 , or 22 , the aphelion ( apoapsis -- farthest point from the Sun ) on anywhere from July 3 to July 5 , the September equinox on September 22 , 23 , or 24 , and the December solstice on December 21 , 22 , or 23 . The diagram shows an exaggerated shape of Earth 's orbit ; the actual orbit is less eccentric than pictured .
United Kingdom
The United Kingdom lies between latitudes 49 ° to 61 ° N , and longitudes 9 ° W to 2 ° E. Northern Ireland shares a 224 - mile ( 360 km ) land boundary with the Republic of Ireland . The coastline of Great Britain is 11,073 miles ( 17,820 km ) long . It is connected to continental Europe by the Channel Tunnel , which at 31 miles ( 50 km ) ( 24 miles ( 38 km ) underwater ) is the longest underwater tunnel in the world .
Jupiter
Flyby missions Spacecraft Closest approach Distance Pioneer 10 December 3 , 1973 130,000 km Pioneer 11 December 4 , 1974 34,000 km Voyager 1 March 5 , 1979 349,000 km Voyager 2 July 9 , 1979 570,000 km Ulysses February 8 , 1992 408,894 km February 4 , 2004 120,000,000 km Cassini December 30 , 2000 10,000,000 km New Horizons February 28 , 2007 2,304,535 km
Moon landing
On 14 December 2013 at 13 : 12 UTC Chang'e 3 soft - landed a rover on the Moon . This was the first lunar soft landing since Luna 24 on 22 August 1976 .
Moon landing
Breaking the six - year string of failures in U.S. attempts to photograph the Moon at close range , the Ranger 7 mission was viewed as a national turning point and instrumental in allowing the key 1965 NASA budget appropriation to pass through the United States Congress intact without a reduction in funds for the Apollo manned Moon landing program . Subsequent successes with Ranger 8 and Ranger 9 further buoyed U.S. hopes .
Speed of light
Given that the equatorial circumference of the Earth is about 7007400750000000000 ♠ 40 075 km and that c is about 7008300000000000000 ♠ 300 000 km / s , the theoretical shortest time for a piece of information to travel half the globe along the surface is about 67 milliseconds . When light is travelling around the globe in an optical fibre , the actual transit time is longer , in part because the speed of light is slower by about 35 % in an optical fibre , depending on its refractive index n . Furthermore , straight lines rarely occur in global communications situations , and delays are created when the signal passes through an electronic switch or signal regenerator .
Moon landing
Failures included three U.S. attempts in 1962 to hard land small seismometer packages released by the main Ranger spacecraft . These surface packages were to use retrorockets to survive landing , unlike the parent vehicle , which was designed to deliberately crash onto the surface . The final three Ranger probes performed successful high altitude lunar reconnaissance photography missions during intentional crash impacts between 2.62 and 2.68 kilometres per second ( 9,400 and 9,600 km / h ) .
Moon landing
Chandrayaan - 1 was launched on 22 October 2008 , 00 : 52 UTC . The impactor , the Moon Impact Probe , impacted near Shackleton Crater at the south pole of the lunar surface at 14 November 2008 , 20 : 31 IST . Chandrayaan - 2 is scheduled for launch in 2018 .
Halley's Comet
In 837 , Halley 's Comet may have passed as close as 0.03 AU ( 3.2 million miles ; 5.1 million kilometers ) from Earth , by far its closest approach . Its tail may have stretched 60 degrees across the sky . It was recorded by astronomers in China , Japan , Germany , the Byzantine Empire , and the Middle East . In 912 , Halley is recorded in the Annals of Ulster , which state `` A dark and rainy year . A comet appeared . ''
Earth's orbit
Because of the axial tilt of the Earth in its orbit , the maximal intensity of Sun rays hits the Earth 23.4 degrees north of equator at the June Solstice ( at the Tropic of Cancer ) , and 23.4 degrees south of equator at the December Solstice ( at the Tropic of Capricorn ) .
Mount Everest
The elevation of 8,848 m ( 29,029 ft ) was first determined by an Indian survey in 1955 , made closer to the mountain , also using theodolites . It was subsequently reaffirmed by a 1975 Chinese measurement of 8,848.13 m ( 29,029.30 ft ) . In both cases the snow cap , not the rock head , was measured . In May 1999 an American Everest Expedition , directed by Bradford Washburn , anchored a GPS unit into the highest bedrock . A rock head elevation of 8,850 m ( 29,035 ft ) , and a snow / ice elevation 1 m ( 3 ft ) higher , were obtained via this device . Although it has not been officially recognised by Nepal , this figure is widely quoted . Geoid uncertainty casts doubt upon the accuracy claimed by both the 1999 and 2005 surveys .
Lunar eclipse
A central lunar eclipse is a total lunar eclipse during which the moon passes through the centre of the Earth 's shadow . These are relatively rare .
Moon landing
The United States ' Apollo 11 was the first manned mission to land on the Moon , on 20 July 1969 . There have been six manned U.S. landings ( between 1969 and 1972 ) and numerous unmanned landings , with no soft landings happening from 22 August 1976 until 14 December 2013 .
Earth
Earth 's interior , like that of the other terrestrial planets , is divided into layers by their chemical or physical ( rheological ) properties . The outer layer is a chemically distinct silicate solid crust , which is underlain by a highly viscous solid mantle . The crust is separated from the mantle by the Mohorovičić discontinuity . The thickness of the crust varies from about 6 kilometres ( 3.7 mi ) under the oceans to 30 -- 50 km ( 19 -- 31 mi ) for the continents . The crust and the cold , rigid , top of the upper mantle are collectively known as the lithosphere , and it is of the lithosphere that the tectonic plates are composed . Beneath the lithosphere is the asthenosphere , a relatively low - viscosity layer on which the lithosphere rides . Important changes in crystal structure within the mantle occur at 410 and 660 km ( 250 and 410 mi ) below the surface , spanning a transition zone that separates the upper and lower mantle . Beneath the mantle , an extremely low viscosity liquid outer core lies above a solid inner core . The Earth 's inner core might rotate at a slightly higher angular velocity than the remainder of the planet , advancing by 0.1 -- 0.5 ° per year . The radius of the inner core is about one fifth of that of Earth .
Earth
The Sun will evolve to become a red giant in about 7000500000000000000 ♠ 5 Bys . Models predict that the Sun will expand to roughly 1 AU ( 150 million km ; 93 million mi ) , about 250 times its present radius . Earth 's fate is less clear . As a red giant , the Sun will lose roughly 30 % of its mass , so , without tidal effects , Earth will move to an orbit 1.7 AU ( 250 million km ; 160 million mi ) from the Sun when the star reaches its maximum radius . Most , if not all , remaining life will be destroyed by the Sun 's increased luminosity ( peaking at about 5,000 times its present level ) . A 2008 simulation indicates that Earth 's orbit will eventually decay due to tidal effects and drag , causing it to enter the Sun 's atmosphere and be vaporized .
Equator
In two widely used geodetic standards , the Equator is modelled as a circle whose radius is a whole number of metres . In 1976 the IAU chose a radius of 6,378.140 kilometres ( 3,963.192 mi ) ( codified as the IAU - 1976 value ) , later refined by the IUGG to 6,378.137 kilometres ( 3,963.191 mi ) and adopted in WGS - 84 . Despite this change , the yet more recent IAU - 2000 retained the old IAU - 1976 value . If it were really circular , the length of the Equator would be exactly 2π times the radius , namely 40,075.036 kilometres ( 24,901.473 mi ) . However , due to the effect of tidal force on the Earth 's surface the actual circumference at the equator is about 40,075.16 kilometres ( 24,901.55 mi ) .
Equator
The precise location of the Equator is not truly fixed ; the true equatorial plane is perpendicular to the Earth 's spin axis , which drifts about 9 metres ( 30 ft ) during a year . This effect must be accounted for in detailed geophysical measurements .
Space Race
The US reacted to the Luna program by embarking on the Ranger program in 1959 , managed by NASA 's Jet Propulsion Laboratory . The Block I Ranger 1 and Ranger 2 suffered Atlas - Agena launch failures in August and November 1961 . The 727 - pound ( 330 kg ) Block II Ranger 3 launched successfully on January 26 , 1962 , but missed the Moon . The 730 - pound ( 330 kg ) Ranger 4 became the first US spacecraft to reach the Moon , but its solar panels and navigational system failed near the Moon and it impacted the far side without returning any scientific data . Ranger 5 ran out of power and missed the Moon by 725 kilometers ( 391 nmi ) on October 21 , 1962 . The first successful Ranger mission was the 806 - pound ( 366 kg ) Block III Ranger 7 which impacted on July 31 , 1964 .
Earth
The mean heat loss from Earth is 7001870000000000000 ♠ 87 mW m , for a global heat loss of 7013442000000000000 ♠ 4.42 × 10 W. A portion of the core 's thermal energy is transported toward the crust by mantle plumes , a form of convection consisting of upwellings of higher - temperature rock . These plumes can produce hotspots and flood basalts . More of the heat in Earth is lost through plate tectonics , by mantle upwelling associated with mid-ocean ridges . The final major mode of heat loss is through conduction through the lithosphere , the majority of which occurs under the oceans because the crust there is much thinner than that of the continents .
Moon landing
In total , twenty - four U.S. astronauts have traveled to the Moon . Three have made the trip twice , and twelve have walked on its surface . Apollo 8 was a lunar - orbit - only mission , Apollo 10 included undocking and Descent Orbit Insertion ( DOI ) , followed by LM staging to CSM redocking , while Apollo 13 , originally scheduled as a landing , ended up as a lunar fly - by , by means of free return trajectory ; thus , none of these missions made landings . Apollo 7 and Apollo 9 were Earth - orbit - only missions . Apart from the inherent dangers of manned Moon expeditions as seen with Apollo 13 , one reason for their cessation according to astronaut Alan Bean is the cost it imposes in government subsidies .
Wikipedia:Citing sources
^ Miller , The Sun , p. 23 . ^ Brown , `` Size of the Moon '' , p. 46 . ^ Miller , The Sun , p. 34 .
Venus
Venus is one of the four terrestrial planets in the Solar System , meaning that it is a rocky body like Earth . It is similar to Earth in size and mass , and is often described as Earth 's `` sister '' or `` twin '' . The diameter of Venus is 12,103.6 km ( 7,520.8 mi ) -- only 638.4 km ( 396.7 mi ) less than Earth 's -- and its mass is 81.5 % of Earth 's . Conditions on the Venusian surface differ radically from those on Earth because its dense atmosphere is 96.5 % carbon dioxide , with most of the remaining 3.5 % being nitrogen .
Moon landing
Luna 10 became the first spacecraft to orbit the Moon on 3 April 1966 .
Moon landing
To date , the United States is the only country to have successfully conducted manned missions to the Moon , with the last departing the lunar surface in December 1972 .
Earth
The atmospheric pressure at Earth 's sea level averages 101.325 kPa ( 14.696 psi ) , with a scale height of about 8.5 km ( 5.3 mi ) . A dry atmosphere is composed of 78.084 % nitrogen , 20.946 % oxygen , 0.934 % argon , and trace amounts of carbon dioxide and other gaseous molecules . Water vapor content varies between 0.01 % and 4 % but averages about 1 % . The height of the troposphere varies with latitude , ranging between 8 km ( 5 mi ) at the poles to 17 km ( 11 mi ) at the equator , with some variation resulting from weather and seasonal factors .
Satellite
Instead of being de-orbited , most satellites are either left in their current orbit or moved to a graveyard orbit . As of 2002 , the FCC requires all geostationary satellites to commit to moving to a graveyard orbit at the end of their operational life prior to launch . In cases of uncontrolled de-orbiting , the major variable is the solar flux , and the minor variables the components and form factors of the satellite itself , and the gravitational perturbations generated by the Sun and the Moon ( as well as those exercised by large mountain ranges , whether above or below sea level ) . The nominal breakup altitude due to aerodynamic forces and temperatures is 78 km , with a range between 72 and 84 km . Solar panels , however , are destroyed before any other component at altitudes between 90 and 95 km .
Coordinated Universal Time
In 1958 , data was published linking the frequency for the caesium transition , newly established , with the ephemeris second . The ephemeris second is the duration of time that , when used as the independent variable in the laws of motion that govern the movement of the planets and moons in the solar system , cause the laws of motion to accurately predict the observed positions of solar system bodies . Within the limits of observing accuracy , ephemeris seconds are of constant length , as are atomic seconds . This publication allowed a value to be chosen for the length of the atomic second that would work properly with the celestial laws of motion .
Moon landing
U.S. mission Mass ( kg ) Booster Launched Mission goal Mission result Lunar Orbiter 1 386 Atlas -- Agena 10 August 1966 Lunar orbiter Success -- 1,160 km X 189 km x 12 deg orbit , 208 m period , 80 - day photography mission Lunar Orbiter 2 386 Atlas -- Agena 6 November 1966 Lunar orbiter Success -- 1,860 km X 52 km x 12 deg orbit , 208 m period , 339 - day photography mission Lunar Orbiter 3 386 Atlas -- Agena 5 February 1967 Lunar orbiter Success -- 1,860 km X 52 km x 21 deg orbit , 208 m period , 246 - day photography mission Lunar Orbiter 4 386 Atlas -- Agena 4 May 1967 Lunar orbiter Success -- 6,111 km X 2,706 km x 86 deg orbit , 721 m period , 180 - day photography mission Lunar Orbiter 5 386 Atlas -- Agena 1 August 1967 Lunar orbiter Success -- 6,023 km X 195 km x 85 deg orbit , 510 m period , 183 - day photography mission
Global Positioning System
Global Positioning System ( GPS ) Country / ies of origin United States Operator ( s ) AFSPC Type Military , civilian Status Operational Coverage Global Accuracy 5 meters Constellation size Total satellites 33 Satellites in orbit 31 First launch February 1978 ; 40 years ago ( 1978 - 02 ) Total launches 72 Orbital characteristics Regime ( s ) 6x MEO planes Orbital height 20,180 km ( 12,540 mi )
Quito
La Mitad del Mundo ( the middle of the world ) is a small village administered by the prefecture of the province of Pichincha , 35 kilometres ( 22 mi ) north of Quito . It has since been determined , with the use of Global Positioning System technology , that the actual equator is some 240 metres ( 790 ft ) north of the monument area . Nearby is the Intiñan Solar Museum , which may be closer to the true equator . The Intiñan Solar Museum provides a demonstration which purports to show the Coriolis force causing a clockwise rotation of sink water a few meters south of the equator and a counterclockwise rotation a few meters north , but many scientific sources claim that this is implausible . ( An African equator demonstration purports to show the Coriolis force causing a clockwise rotation of sink water a few meters north of the equator and a counterclockwise rotation a few meters south. )
Moon landing
LADEE was launched on 7 September 2013 . The mission ended on 18 April 2014 , when the spacecraft 's controllers intentionally crashed LADEE into the far side of the Moon , which , later , was determined to be near the eastern rim of Sundman V crater .
Lunar eclipse
Recent total eclipses April 15 , 2014 October 8 , 2014 April 4 , 2015 September 28 , 2015
Earth
Earth 's atmosphere and oceans were formed by volcanic activity and outgassing . Water vapor from these sources condensed into the oceans , augmented by water and ice from asteroids , protoplanets , and comets . In this model , atmospheric `` greenhouse gases '' kept the oceans from freezing when the newly forming Sun had only 70 % of its current luminosity . By 7000350000000000000 ♠ 3.5 Bya , Earth 's magnetic field was established , which helped prevent the atmosphere from being stripped away by the solar wind .
Season
Compared to axial tilt , other factors contribute little to seasonal temperature changes . The seasons are not the result of the variation in Earth 's distance to the Sun because of its elliptical orbit . In fact , Earth reaches perihelion ( the point in its orbit closest to the Sun ) in January , and it reaches aphelion ( the point farthest from the Sun ) in July , so the slight contribution of orbital eccentricity opposes the temperature trends of the seasons in the Northern Hemisphere . In general , the effect of orbital eccentricity on Earth 's seasons is a 7 % variation in sunlight received .
Edmond Halley
In 1716 , Halley suggested a high - precision measurement of the distance between the Earth and the Sun by timing the transit of Venus . In doing so , he was following the method described by James Gregory in Optica Promota ( in which the design of the Gregorian telescope is also described ) . It is reasonable to assume Halley possessed and had read this book given that the Gregorian design was the principal telescope design used in astronomy in Halley 's day . It is not to Halley 's credit that he failed to acknowledge Gregory 's priority in this matter . In 1718 he discovered the proper motion of the `` fixed '' stars by comparing his astrometric measurements with those given in Ptolemy 's Almagest . Arcturus and Sirius were two noted to have moved significantly , the latter having progressed 30 arc minutes ( about the diameter of the moon ) southwards in 1800 years .
Sundial
The length of a human shadow ( or of any vertical object ) can be used to measure the sun 's elevation and , thence , the time . The Venerable Bede gave a table for estimating the time from the length of one 's shadow in feet , on the assumption that a monk 's height is six times the length of his foot . Such shadow lengths will vary with the geographical latitude and with the time of year . For example , the shadow length at noon is short in summer months , and long in winter months .