vania-janet/multiturn-rag-retrieval-data huggingface dataset:
Great Wall of China
The claim that the Great Wall is visible from the moon has been debunked many times , but is still ingrained in popular culture . The wall is a maximum 9.1 m ( 29 ft 10 in ) wide , and is about the same color as the soil surrounding it . Based on the optics of resolving power ( distance versus the width of the iris : a few millimeters for the human eye , meters for large telescopes ) only an object of reasonable contrast to its surroundings which is 110 km ( 70 mi ) or more in diameter ( 1 arc - minute ) would be visible to the unaided eye from the Moon , whose average distance from Earth is 384,393 km ( 238,851 mi ) . The apparent width of the Great Wall from the Moon is the same as that of a human hair viewed from 3 km ( 2 mi ) away . To see the wall from the Moon would require spatial resolution 17,000 times better than normal ( 20 / 20 ) vision . Unsurprisingly , no lunar astronaut has ever claimed to have seen the Great Wall from the Moon .
Earth's orbit
Earth 's orbit is the trajectory along which Earth travels around the Sun . The average distance between the Earth and the Sun is 149.60 million km ( 92.96 million mi ) , and one complete orbit takes 365.256 days ( 1 sidereal year ) , during which time Earth has traveled 940 million km ( 584 million mi ) . Earth 's orbit has an eccentricity of 0.0167 .
Speed of light
Similarly , communications between the Earth and spacecraft are not instantaneous . There is a brief delay from the source to the receiver , which becomes more noticeable as distances increase . This delay was significant for communications between ground control and Apollo 8 when it became the first manned spacecraft to orbit the Moon : for every question , the ground control station had to wait at least three seconds for the answer to arrive . The communications delay between Earth and Mars can vary between five and twenty minutes depending upon the relative positions of the two planets . As a consequence of this , if a robot on the surface of Mars were to encounter a problem , its human controllers would not be aware of it until at least five minutes later , and possibly up to twenty minutes later ; it would then take a further five to twenty minutes for instructions to travel from Earth to Mars .
Equator
The sea - level surface of the Earth ( the geoid ) is irregular , so the actual length of the Equator is not so easy to determine . Aviation Week and Space Technology on 9 October 1961 reported that measurements using the Transit IV - A satellite had shown the equatorial `` diameter '' from longitude 11 ° West to 169 ° East to be 1,000 feet ( 300 m ) greater than its `` diameter '' ninety degrees away .
Earth
7002298257222101000 ♠ 298.257 222 101 ( ETRS89 ) Circumference 40 075.017 km equatorial ( 24 901.461 mi ) 40 007.86 km meridional ( 24 859.73 mi ) Surface area 510 072 000 km ( 196 940 000 sq mi ) 148 940 000 km land ( 57 510 000 sq mi ; 29.2 % ) 361 132 000 km water ( 139 434 000 sq mi ; 70.8 % ) Volume 7021108320999999999 ♠ 1.083 21 × 10 km ( 7011259876000000000 ♠ 2.598 76 × 10 cu mi ) Mass 7024597237000000000 ♠ 5.972 37 × 10 kg ( 7024597236001731600 ♠ 1.316 68 × 10 lb ) ( 7024596565000000000 ♠ 3.0 × 10 M ) Mean density 5.514 g / cm ( 0.1992 lb / cu in ) Surface gravity 9.807 m / s ( 7000100000000000000 ♠ 1 g ; 32.18 ft / s ) Moment of inertia factor 0.3307 Escape velocity 11.186 km / s ( 40 270 km / h ; 25 020 mph ) Sidereal rotation period 7004861641003520000 ♠ 0.997 269 68 d ( 23h 56m 4.100 s ) Equatorial rotation velocity 0.4651 km / s ( 1674.4 km / h ; 1040.4 mph ) Axial tilt 6999409092629495479 ♠ 23.439 2811 ° Albedo 0.367 geometric 0.306 Bond Surface temp .
Lunar distance (astronomy)
Due to the modern accessibility to accurate timing devices , high resolution digital cameras , GPS receivers , powerful computers and near instantaneous communication , it has become possible for amateur astronomers to make high accuracy measurements of the lunar distance .
Moon landing
Manned Earth - orbiting vehicles such as the Space Shuttle return to Earth from speeds of around 17,000 miles per hour ( 27,000 km / h ; 7,600 m / s ) . Due to the effects of gravity , a vehicle returning from the Moon hits Earth 's atmosphere at a much higher speed of around 25,000 miles per hour ( 40,000 km / h ; 11,000 m / s ) . The g - loading on astronauts during the resulting deceleration can be at the limits of human endurance even during a nominal reentry . Slight variations in the vehicle flight path and reentry angle during a return from the Moon can easily result in fatal levels of deceleration force .
Earth's orbit
In modern times , Earth 's perihelion occurs around January 3 , and the aphelion around July 4 ( for other eras , see precession and Milankovitch cycles ) . The changing Earth -- Sun distance results in an increase of about 6.9 % in total solar energy reaching the Earth at perihelion relative to aphelion . Since the southern hemisphere is tilted toward the Sun at about the same time that the Earth reaches the closest approach to the Sun , the southern hemisphere receives slightly more energy from the Sun than does the northern over the course of a year . However , this effect is much less significant than the total energy change due to the axial tilt , and most of the excess energy is absorbed by the higher proportion of water in the southern hemisphere .
Lunar phase
The approximate age of the moon , and hence the approximate phase , can be calculated for any date by calculating the number of days since a known new moon ( such as January 1 , 1900 or August 11 , 1999 ) and reducing this modulo 29.530588853 ( the length of a synodic month ) . The difference between two dates can be calculated by subtracting the Julian Day Number of one from that of the other , or there are simpler formulae giving ( for instance ) the number of days since December 31 , 1899 . However , this calculation assumes a perfectly circular orbit and makes no allowance for the time of day at which the new moon happened , therefore may be incorrect by several hours ( it also becomes less accurate the larger the difference between the required date and the reference date ) ; it is accurate enough to use in a novelty clock application showing moon phase , but specialist usage taking account of lunar apogee and perigee requires a more elaborate calculation .
Earth
Earth , along with the Solar System , is situated in the Milky Way and orbits about 28,000 light - years from its center . It is about 20 light - years above the galactic plane in the Orion Arm .
Earth
In modern times , Earth 's perihelion occurs around 3 January , and its aphelion around 4 July . These dates change over time due to precession and other orbital factors , which follow cyclical patterns known as Milankovitch cycles . The changing Earth -- Sun distance causes an increase of about 6.9 % in solar energy reaching Earth at perihelion relative to aphelion . Because the Southern Hemisphere is tilted toward the Sun at about the same time that Earth reaches the closest approach to the Sun , the Southern Hemisphere receives slightly more energy from the Sun than does the northern over the course of a year . This effect is much less significant than the total energy change due to the axial tilt , and most of the excess energy is absorbed by the higher proportion of water in the Southern Hemisphere .
Moon landing
The Ranger 1 and 2 Block I missions were virtually identical . Spacecraft experiments included a Lyman - alpha telescope , a rubidium - vapor magnetometer , electrostatic analyzers , medium - energy - range particle detectors , two triple coincidence telescopes , a cosmic - ray integrating ionization chamber , cosmic dust detectors , and scintillation counters . The goal was to place these Block I spacecraft in a very high Earth orbit with an apogee of 110,000 kilometres ( 68,000 mi ) and a perigee of 60,000 kilometres ( 37,000 mi ) .
Metrication in the United States
In early 2007 , NASA announced that it would use metric units for all operations on the lunar surface upon its return to the Moon , then projected for 2020 . However , NASA 's lunar return program was canceled in 2010 .
Earth's orbit
As seen from Earth , the planet 's orbital prograde motion makes the Sun appear to move with respect to other stars at a rate of about 1 ° ( or a Sun or Moon diameter every 12 hours ) eastward per solar day . Earth 's orbital speed averages about 30 km / s ( 108,000 km / h ; 67,000 mph ) , which is fast enough to cover the planet 's diameter in 7 minutes and the distance to the Moon in 4 hours .
Communications satellite
Geostationary satellites have a geostationary orbit ( GEO ) , which is 35,786 kilometres ( 22,236 mi ) from Earth 's surface . This orbit has the special characteristic that the apparent position of the satellite in the sky when viewed by a ground observer does not change , the satellite appears to `` stand still '' in the sky . This is because the satellite 's orbital period is the same as the rotation rate of the Earth . The advantage of this orbit is that ground antennas do not have to track the satellite across the sky , they can be fixed to point at the location in the sky the satellite appears . Medium Earth orbit ( MEO ) satellites are closer to Earth . Orbital altitudes range from 2,000 to 35,786 kilometres ( 1,243 to 22,236 mi ) above Earth . The region below medium orbits is referred to as low Earth orbit ( LEO ) , and is about 160 to 2,000 kilometres ( 99 to 1,243 mi ) above Earth .
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life . According to radiometric dating and other sources of evidence , Earth formed over 4.5 billion years ago . Earth 's gravity interacts with other objects in space , especially the Sun and the Moon , Earth 's only natural satellite . Earth revolves around the Sun in 365.26 days , a period known as an Earth year . During this time , Earth rotates about its axis about 366.26 times .
Earth
The tiny near - Earth asteroid 2006 RH 120 makes close approaches to the Earth -- Moon system roughly every twenty years . During these approaches , it can orbit Earth for brief periods of time .
Equator
The geographical mile is defined as one arc minute of the Equator , so it has different values depending on which radius is assumed . For example , by WSG - 84 , the distance is 1,855.3248 metres ( 6,087.024 ft ) , while by IAU - 2000 , it is 1,855.3257 metres ( 6,087.027 ft ) . This is a difference of less than one millimeter over the total distance ( approximately 1.86 kilometres ( 1.16 mi ) ) .
Earth
Characteristics Diameter 7006347480000000000 ♠ 3,474.8 km Mass 7022734900000000000 ♠ 7.349 × 10 kg Semi-major axis 7008384400000000000 ♠ 384,400 km Orbital period 27 7 43.7 Main
Mount Everest
The summit of Chimborazo in Ecuador is 2,168 m ( 7,113 ft ) farther from earth 's centre ( 6,384.4 km ( 3,967.1 mi ) ) than that of Everest ( 6,382.3 km ( 3,965.8 mi ) ) , because the earth bulges at the equator . This is despite Chimborazo having a peak 6,268 m ( 20,564.3 ft ) above sea level versus Mount Everest 's 8,848 m ( 29,028.9 ft ) .
Moon landing
Mission name Lunar lander Lunar landing date Lunar liftoff date Lunar landing site Duration on lunar surface Crew Number of EVAs Total EVA Time ( HH : MM ) Apollo 11 Eagle 20 July 1969 21 July 1969 Sea of Tranquility 21 : 31 Neil Armstrong , Edwin `` Buzz '' Aldrin 2 : 31 Apollo 12 Intrepid 19 November 1969 21 November 1969 Ocean of Storms 1 - day , 7 : 31 Charles `` Pete '' Conrad , Alan Bean 7 : 45 Apollo 14 Antares 5 February 1971 6 February 1971 Fra Mauro 1 - day , 9 : 30 Alan B. Shepard , Edgar Mitchell 9 : 21 Apollo 15 Falcon 30 July 1971 2 August 1971 Hadley Rille 2 days , 18 : 55 David Scott , James Irwin 18 : 33 Apollo 16 Orion 21 April 1972 24 April 1972 Descartes Highlands 2 days , 23 : 02 John Young , Charles Duke 20 : 14 Apollo 17 Challenger 11 December 1972 14 December 1972 Taurus -- Littrow 3 days , 2 : 59 Eugene Cernan , Harrison `` Jack '' Schmitt 22 : 04
Jupiter
The Galilean moons , compared to Earth 's Moon Name IPA Diameter Mass Orbital radius Orbital period km % kg % km % days % Io / ˈaɪ. oʊ / 3,643 105 8.9 × 10 120 421,700 110 1.77 7 Europa / jʊˈroʊpə / 3,122 90 4.8 × 10 65 671,034 175 3.55 13 Ganymede / ˈɡænimiːd / 5,262 150 14.8 × 10 200 1,070,412 280 7.15 26 Callisto / kəˈlɪstoʊ / 4,821 140 10.8 × 10 150 1,882,709 490 16.69 61 The Galilean moons Io , Europa , Ganymede , Callisto ( in order of increasing distance from Jupiter )
2004 Indian Ocean earthquake and tsunami
The shift of mass and the massive release of energy very slightly altered the Earth 's rotation . The exact amount is not yet known , but theoretical models suggest the earthquake shortened the length of a day by 2.68 microseconds , due to a decrease in the oblateness of the Earth . It also caused the Earth to minutely `` wobble '' on its axis by up to 2.5 cm ( 1 in ) in the direction of 145 ° east longitude , or perhaps by up to 5 or 6 cm ( 2.0 or 2.4 in ) . However , because of tidal effects of the Moon , the length of a day increases at an average of 15 μs per year , so any rotational change due to the earthquake will be lost quickly . Similarly , the natural Chandler wobble of the Earth , which in some cases can be up to 15 m ( 50 ft ) , will eventually offset the minor wobble produced by the earthquake .
Earth
Lord Kelvin used thermodynamics to estimate the age of Earth to be between 20 million and 400 million years in 1864 , sparking a vigorous debate on the subject ; it was only when radioactivity and radioactive dating were discovered in the late 19th and early 20th centuries that a reliable mechanism for determining Earth 's age was established , proving the planet to be billions of years old . The perception of Earth shifted again in the 20th century when humans first viewed it from orbit , and especially with photographs of Earth returned by the Apollo program . Clickable
Satellite
Low Earth orbit ( LEO ) : Geocentric orbits ranging in altitude from 180 km - 2,000 km ( 1,200 mi ) Medium Earth orbit ( MEO ) : Geocentric orbits ranging in altitude from 2,000 km ( 1,200 mi ) - 35,786 km ( 22,236 mi ) . Also known as an intermediate circular orbit . Geosynchronous orbit ( GEO ) : Geocentric circular orbit with an altitude of 35,786 kilometres ( 22,236 mi ) . The period of the orbit equals one sidereal day , coinciding with the rotation period of the Earth . The speed is approximately 3,000 metres per second ( 9,800 ft / s ) . High Earth orbit ( HEO ) : Geocentric orbits above the altitude of geosynchronous orbit 35,786 km ( 22,236 mi ) . Orbital
Moon landing
No cameras were carried by the Ranger landers , and no pictures were to be captured from the lunar surface during the mission . Instead , the 3.1 metres ( 10 ft ) Ranger Block II mother ship carried a 200 - scan - line television camera which was to capture images during the free - fall descent to the lunar surface . The camera was designed to transmit a picture every 10 seconds . Seconds before impact , at 5 and 0.6 kilometres ( 3.11 and 0.37 mi ) above the lunar surface , the Ranger mother ships took picture ( which may be viewed here ) .
Moon landing
Progress in space exploration has recently broadened the phrase moon landing to include other moons in the Solar System as well . The Huygens probe of the Cassini -- Huygens mission to Saturn performed a successful unmanned moon landing on Titan in 2005 . Similarly , the Soviet probe Phobos 2 came within 120 mi ( 190 km ) of performing an unmanned moon landing on Mars ' moon Phobos in 1989 before radio contact with that lander was suddenly lost . A similar Russian sample return mission called Fobos - Grunt ( `` grunt '' means `` soil '' in Russian ) launched in November 2011 , but stalled in low Earth orbit . There is widespread interest in performing a future moon landing on Jupiter 's Europa moon to drill down and explore the possible liquid water ocean beneath its icy surface .
Equator
The Earth bulges slightly at the Equator ; the `` average '' diameter of the Earth is 12,750 kilometres ( 7,922 mi ) , but the diameter at the Equator is about 43 kilometres ( 27 mi ) greater than at the poles .
Lunar distance (astronomy)
Other experimental methods of measuring the lunar distance that can be performed by amateur astronomers involve :
Main sequence
In April , 2018 , astronomers reported the detection of the most distant `` ordinary '' ( ie , main sequence ) star , named Icarus ( formally , MACS J1149 Lensed Star 1 ) , at 9 billion light - years away from Earth .
Equator
The earth is commonly modeled as a sphere flattened 0.336 % along its axis . This makes the Equator 0.16 % longer than a meridian ( a great circle passing through the two poles ) . The IUGG standard meridian is , to the nearest millimetre , 40,007.862917 kilometres ( 24,859.733480 mi ) , one arc minute of which is 1,852.216 metres ( 6,076.82 ft ) , explaining the SI standardization of the nautical mile as 1,852 metres ( 6,076 ft ) , more than 3 metres ( 9.8 ft ) less than the geographical mile .
Moon landing
Luna 16 was the first robotic probe to land on the Moon and safely return a sample of lunar soil back to Earth . It represented the first lunar sample return mission by the Soviet Union , and was the third lunar sample return mission overall , following the Apollo 11 and Apollo 12 missions . This mission was later successfully repeated by Luna 20 ( 1972 ) and Luna 24 ( 1976 ) .
Moon landing
The Chinese lunar orbiter Chang'e 1 , launched 24 October 2007 , 10 : 05 UTC , executed a controlled crash onto the surface of the Moon on 1 March 2009 , 20 : 44 GMT , after a 16 - month mission .
Satellite
Sun - synchronous orbit : An orbit which combines altitude and inclination in such a way that the satellite passes over any given point of the planets ' surface at the same local solar time . Such an orbit can place a satellite in constant sunlight and is useful for imaging , spy , and weather satellites . Moon orbit : The orbital characteristics of Earth 's Moon . Average altitude of 384,403 kilometers ( 238,857 mi ) , elliptical -- inclined orbit .
Moon landing
returned 0.10 kg of Moon soil back to Earth Mare Fecunditatis 000.68 S 056.30 E Luna - 17 5,700 Proton 10 November 1970 Lunar rover Success -- Lunokhod - 1 rover traveled 10.5 km across lunar surface Mare Imbrium 038.28 N 325.00 E Luna - 18 5,750 Proton 2 September 1971 Sample return Failure -- lunar crash impact Mare Fecunditatis 003.57 N 056.50 E Luna - 20 5,727 Proton 14 February 1972 Sample return Success -- returned 0.05 kg of Moon soil back to Earth Mare Fecunditatis 003.57 N 056.50 E Luna - 21 5,950 Proton 8 January 1973 Lunar rover Success -- Lunokhod - 2 rover traveled 37.0 km across lunar surface LeMonnier Crater 025.85 N 030.45 E Luna - 23 5,800 Proton 28 October 1974 Sample return Failure -- Moon landing achieved , but malfunction prevented sample return Mare Crisium 012.00 N 062.00 E Proton 16 October 1975 Sample return Failure -- booster malfunction , failed to reach Earth orbit Luna - 24 5,800 Proton 9 August 1976 Sample return Success -- returned 0.17 kg of Moon soil back to Earth Mare Crisium 012.25 N 062.20 E
Earth
Earth 's rotation period relative to the Sun -- its mean solar day -- is 86,400 seconds of mean solar time ( 86,400.0025 SI seconds ) . Because Earth 's solar day is now slightly longer than it was during the 19th century due to tidal deceleration , each day varies between 0 and 2 SI ms longer .
Speed of light
Speed of light Sunlight takes about 8 minutes 17 seconds to travel the average distance from the surface of the Sun to the Earth . Exact values metres per second 7008299792458000000 ♠ 299 792 458 Planck length per Planck time ( i.e. , Planck units ) Approximate values ( to three significant digits ) kilometres per hour 7009108000000000000 ♠ 1080000000 miles per second 7005186000000000000 ♠ 186 000 miles per hour 7008671000000000000 ♠ 671 000 000 astronomical units per day 173 parsecs per year 0.307 Approximate light signal travel times Distance Time one foot 1.0 ns one metre 3.3 ns from geostationary orbit to Earth 119 ms the length of Earth 's equator 134 ms from Moon to Earth 1.3 s from Sun to Earth ( 1 AU ) 8.3 min one light year 1.0 year one parsec 3.26 years from nearest star to Sun ( 1.3 pc ) 4.2 years from the nearest galaxy ( the Canis Major Dwarf Galaxy ) to Earth 7011788940000000000 ♠ 25 000 years across the Milky Way 7012315576000000000 ♠ 100 000 years from the Andromeda Galaxy to Earth 2.5 million years from Earth to the edge of the observable universe 46.5 billion years
Earth
Earth 's rotation period relative to the fixed stars , called its stellar day by the International Earth Rotation and Reference Systems Service ( IERS ) , is 86,164.0989 seconds of mean solar time ( UT1 ) , or 23 56 4.0989 . Earth 's rotation period relative to the precessing or moving mean vernal equinox , misnamed its sidereal day , is 86,164.0905 seconds of mean solar time ( UT1 ) ( 23 56 4.0905 ) . Thus the sidereal day is shorter than the stellar day by about 8.4 ms . The length of the mean solar day in SI seconds is available from the IERS for the periods 1623 -- 2005 and 1962 -- 2005 .
Moon landing
A Moon landing is the arrival of a spacecraft on the surface of the Moon . This includes both manned and unmanned ( robotic ) missions . The first human - made object to reach the surface of the Moon was the Soviet Union 's Luna 2 mission , on 13 September 1959 .
Moon landing
SELENE or Kaguya was launched on 14 September 2007 . After successfully orbiting the Moon for a year and eight months , the main orbiter was instructed to impact on the lunar surface near the crater Gill at 18 : 25 UTC on 10 June 2009 .
Global Positioning System
The receiver 's Earth - centered solution location is usually converted to latitude , longitude and height relative to an ellipsoidal Earth model . The height may then be further converted to height relative to the geoid ( e.g. , EGM96 ) ( essentially , mean sea level ) . These coordinates may be displayed , e.g. , on a moving map display , and / or recorded and / or used by some other system ( e.g. , a vehicle guidance system ) .
Mars
Mars can easily be seen from Earth with the naked eye , as can its reddish coloring . Its apparent magnitude reaches − 2.91 , which is surpassed only by Jupiter , Venus , the Moon , and the Sun . Optical ground - based telescopes are typically limited to resolving features about 300 kilometers ( 190 mi ) across when Earth and Mars are closest because of Earth 's atmosphere .
Communications satellite
Decades later a project named Communication Moon Relay was a telecommunication project carried out by the United States Navy . Its objective was to develop a secure and reliable method of wireless communication by using the Moon as a passive reflector and natural communications satellite .
Plate tectonics
This was immediately followed by a symposium in Tasmania in March 1956 . In this symposium , the evidence was used in the theory of an expansion of the global crust . In this hypothesis the shifting of the continents can be simply explained by a large increase in size of the Earth since its formation . However , this was unsatisfactory because its supporters could offer no convincing mechanism to produce a significant expansion of the Earth . Certainly there is no evidence that the moon has expanded in the past 3 billion years ; other work would soon show that the evidence was equally in support of continental drift on a globe with a stable radius .
2004 Indian Ocean earthquake and tsunami
The earthquake generated a seismic oscillation of the Earth 's surface of up to 20 -- 30 cm ( 8 -- 12 in ) , equivalent to the effect of the tidal forces caused by the Sun and Moon . The seismic waves of the earthquake were felt across the planet ; as far away as the U.S. state of Oklahoma , where vertical movements of 3 mm ( 0.12 in ) were recorded . By February 2005 , the earthquake 's effects were still detectable as a 20 μm ( 0.02 mm ; 0.0008 in ) complex harmonic oscillation of the Earth 's surface , which gradually diminished and merged with the incessant free oscillation of the Earth more than 4 months after the earthquake .