vania-janet/multiturn-rag-retrieval-data huggingface dataset:
Coordinated Universal Time
As the Earth 's rotation continues to slow , positive leap seconds will be required more frequently . The long - term rate of change of LOD is approximately + 1.7 ms per century . At the end of the 21st century , LOD will be roughly 86,400.004 s , requiring leap seconds every 250 days . Over several centuries , the frequency of leap seconds will become problematic .
Space Race
The Soviet Zond spacecraft was not yet ready for piloted circumlunar missions in 1968 , after five unsuccessful and partially successful automated test launches : Cosmos 146 on March 10 , 1967 ; Cosmos 154 on April 8 , 1967 ; Zond 1967A September 27 , 1967 ; Zond 1967B on November 22 , 1967 . Zond 4 was launched on March 2 , 1968 , and successfully made a circumlunar flight . After its successful flight around the Moon , Zond 4 encountered problems with its Earth reentry on March 9 , and was ordered destroyed by an explosive charge 15,000 meters ( 49,000 ft ) over the Gulf of Guinea . The Soviet official announcement said that Zond 4 was an automated test flight which ended with its intentional destruction , due to its recovery trajectory positioning it over the Atlantic Ocean instead of over the USSR . Earthrise
Hawaii (island)
At its greatest dimension , the island is 93 miles ( 150 km ) across . It has a land area of 4,028 square miles ( 10,430 km ) comprising 62 % of the Hawaiian Islands ' land area . Measured from its sea floor base to its highest peak , Mauna Kea is the world 's tallest mountain , taller than Mount Everest is , since the base of Mount Everest is above sea level . A
Earth
Above the troposphere , the atmosphere is usually divided into the stratosphere , mesosphere , and thermosphere . Each layer has a different lapse rate , defining the rate of change in temperature with height . Beyond these , the exosphere thins out into the magnetosphere , where the geomagnetic fields interact with the solar wind . Within the stratosphere is the ozone layer , a component that partially shields the surface from ultraviolet light and thus is important for life on Earth . The Kármán line , defined as 100 km above Earth 's surface , is a working definition for the boundary between the atmosphere and outer space .
Quasar
In 1962 a breakthrough was achieved . Another radio source , 3C 273 , was predicted to undergo five occultations by the Moon . Measurements taken by Cyril Hazard and John Bolton during one of the occultations using the Parkes Radio Telescope allowed Maarten Schmidt to optically identify the object and obtain an optical spectrum using the 200 - inch Hale Telescope on Mount Palomar . This spectrum revealed the same strange emission lines . Schmidt realized that these were actually spectral lines of hydrogen redshifted at the rate of 15.8 percent . This discovery showed that 3C 273 was receding at a rate of 47,000 km / s . This discovery revolutionized quasar observation and allowed other astronomers to find redshifts from the emission lines from other radio sources . As predicted earlier by Bolton , 3C 48 was found to have a redshift of 37 % of the speed of light .
Leo (constellation)
The star Wolf 359 ( CN Leonis ) , one of the nearest stars to Earth at 7.8 light - years away , is in Leo . Wolf 359 is a red dwarf of magnitude 13.5 ; it periodically brightens by one magnitude or less because it is a flare star . Gliese 436 , a faint star in Leo about 33 light - years away from the Sun , is orbited by a transiting Neptune - mass extrasolar planet .
Magnetosphere of Jupiter
As with Earth 's magnetosphere , the boundary separating the denser and colder solar wind 's plasma from the hotter and less dense one within Jupiter 's magnetosphere is called the magnetopause . The distance from the magnetopause to the center of the planet is from 45 to 100 R ( where R = 71,492 km is the radius of Jupiter ) at the subsolar point -- the unfixed point on the surface at which the Sun would appear directly overhead to an observer . The position of the magnetopause depends on the pressure exerted by the solar wind , which in turn depends on solar activity . In front of the magnetopause ( at a distance from 80 to 130 R from the planet 's center ) lies the bow shock , a wake - like disturbance in the solar wind caused by its collision with the magnetosphere . The region between the bow shock and magnetopause is called the magnetosheath . An
Lunar phase
Photographing the Moon 's phase every day for a month , starting in the evening after sunset , and repeating approximately fifty minutes later each successive day , ending in the morning before sunrise , would create a composite image like the example calendar from May 8 , 2005 , to June 6 , 2005 here in the left . There is no picture on May 20 since a picture would be taken before midnight on May 19 , and after midnight on May 21 . Similarly , on a calendar listing moon rise or set times , some days will appear to be skipped . When the Moon rises just before midnight one night it will rise just after midnight the next ( so too with setting ) . The ' skipped day ' is just a feature of the moon 's eastward movement in relation to the sun , which at most latitudes causes the moon to rise later each day . The moon has a predictable orbit every month .
North Pole
The sea depth at the North Pole has been measured at 4,261 m ( 13,980 ft ) by the Russian Mir submersible in 2007 and at 4,087 m ( 13,410 ft ) by USS Nautilus in 1958 . The nearest land is usually said to be Kaffeklubben Island , off the northern coast of Greenland about 700 km ( 430 mi ) away , though some perhaps semi permanent gravel banks lie slightly closer . The nearest permanently inhabited place is Alert in the Qikiqtaaluk Region , Nunavut , Canada , which is located 817 km ( 508 mi ) from the Pole .
Venus
Flattening 0 Surface area 7014460229999999999 ♠ 4.6023 × 10 km 0.902 Earths Volume 7020928430000000000 ♠ 9.2843 × 10 km 0.866 Earths Mass 7024486749999999999 ♠ 4.8675 × 10 kg 0.815 Earths Mean density 7003524300000000000 ♠ 5.243 g / cm Surface gravity 7000886999999999999 ♠ 8.87 m / s 0.904 g Escape velocity 10.36 km / s ( 6.44 mi / s ) Sidereal rotation period 2992790026400000000 ♠ − 243.025 d ( retrograde ) Equatorial rotation velocity 6.52 km / h ( 1.81 m / s ) Axial tilt 2.64 ° ( for retrograde rotation ) 177.36 ° ( to orbit ) North pole right ascension 18 11 2 272.76 ° North pole declination 67.16 ° Albedo 0.689 ( geometric ) 0.77 ( Bond ) 0.65 ( visual geometric ) Surface temp . min mean max Kelvin 737 K Celsius 462 ° C Apparent magnitude − 4.9 ( crescent ) to − 3.8 ( full ) Angular diameter 9.7 '' -- 66.0 '' Atmosphere Surface pressure 92 bar ( 9.2 MPa ) Composition by volume 96.5 % carbon dioxide 3.5 % nitrogen 0.015 % sulfur dioxide 0.007 % argon 0.002 % water vapour 0.0017 % carbon monoxide 0.0012 % helium 0.0007 % neon trace carbonyl sulfide trace hydrogen chloride trace hydrogen fluoride Jump up ^ Defining the rotation as retrograde , as done by NASA space missions and the USGS , puts Ishtar Terra in the northern hemisphere and makes the axial tilt 2.64 ° . Following the right - hand rule for prograde rotation puts Ishtar Terra in the southern hemisphere and makes the axial tilt 177.36 ° .
Space Race
Apollo 11 left lunar orbit and returned to Earth , landing safely in the Pacific Ocean on July 24 , 1969 . When the spacecraft splashed down , 2,982 days had passed since Kennedy 's commitment to landing a man on the Moon and returning him safely to the Earth before the end of the decade ; the mission was completed with 161 days to spare . With the safe completion of the Apollo 11 mission , the Americans won the race to the Moon .
Season
Over thousands of years , the Earth 's axial tilt and orbital eccentricity vary ( see Milankovitch cycles ) . The equinoxes and solstices move westward relative to the stars while the perihelion and aphelion move eastward . Thus , ten thousand years from now Earth 's northern winter will occur at aphelion and northern summer at perihelion . The severity of seasonal change -- the average temperature difference between summer and winter in location -- will also change over time because the Earth 's axial tilt fluctuates between 22.1 and 24.5 degrees .
Earth
The axial tilt of the Earth is approximately 23.439281 ° with the axis of its orbit plane , always pointing towards the Celestial Poles . Due to Earth 's axial tilt , the amount of sunlight reaching any given point on the surface varies over the course of the year . This causes the seasonal change in climate , with summer in the Northern Hemisphere occurring when the Tropic of Cancer is facing the Sun , and winter taking place when the Tropic of Capricorn in the Southern Hemisphere faces the Sun . During the summer , the day lasts longer , and the Sun climbs higher in the sky . In winter , the climate becomes cooler and the days shorter . In northern temperate latitudes , the Sun rises north of true east during the summer solstice , and sets north of true west , reversing in the winter . The Sun rises south of true east in the summer for the southern temperate zone and sets south of true west .
Exoplanet
In May 2017 , glints of light from Earth , seen as twinkling from an orbiting satellite a million miles away , were found to be reflected light from ice crystals in the atmosphere . The technology used to determine this may be useful in studying the atmospheres of distant worlds , including those of exoplanets .
Earth
Earth 's mass is approximately 7024597000000000000 ♠ 5.97 × 10 kg ( 5,970 Yg ) . It is composed mostly of iron ( 32.1 % ) , oxygen ( 30.1 % ) , silicon ( 15.1 % ) , magnesium ( 13.9 % ) , sulfur ( 2.9 % ) , nickel ( 1.8 % ) , calcium ( 1.5 % ) , and aluminium ( 1.4 % ) , with the remaining 1.2 % consisting of trace amounts of other elements . Due to mass segregation , the core region is estimated to be primarily composed of iron ( 88.8 % ) , with smaller amounts of nickel ( 5.8 % ) , sulfur ( 4.5 % ) , and less than 1 % trace elements .
Moon landing
In 1951 , science fiction writer Arthur C. Clarke forecast that man would reach the Moon by 1978 .
Venus
Venus is the second planet from the Sun , orbiting it every 224.7 Earth days . It has the longest rotation period ( 243 days ) of any planet in the Solar System and rotates in the opposite direction to most other planets . It has no natural satellites . It is named after the Roman goddess of love and beauty . It is the second - brightest natural object in the night sky after the Moon , reaching an apparent magnitude of − 4.6 -- bright enough to cast shadows at night and , rarely , visible to the naked eye in broad daylight . Orbiting within Earth 's orbit , Venus is an inferior planet and never appears to venture far from the Sun ; its maximum angular distance from the Sun ( elongation ) is 47.8 ° .
Jupiter
A 340 - kilogram titanium atmospheric probe was released from the spacecraft in July 1995 , entering Jupiter 's atmosphere on December 7 . It parachuted through 150 km ( 93 mi ) of the atmosphere at a speed of about 2,575 km / h ( 1600 mph ) and collected data for 57.6 minutes before it was crushed by the pressure of about 23 atmospheres at a temperature of 153 ° C. It melted thereafter , and possibly vaporized . The Galileo orbiter itself experienced a more rapid version of the same fate when it was deliberately steered into the planet on September 21 , 2003 at a speed of over 50 km / s to avoid any possibility of it crashing into and possibly contaminating Europa , a moon which has been hypothesized to have the possibility of harboring life .
Moon landing
Unlike other international rivalries , the Space Race has remained unaffected in a direct way regarding the desire for territorial expansion . After the successful landings on the Moon , the U.S. explicitly disclaimed the right to ownership of any part of the Moon .
Moon landing
The Chinese lunar orbiter Chang'e 1 executed a controlled crash onto the surface of the Moon on 1 March 2009 . The rover mission Chang'e 3 was launched on 1 December 2013 and soft - landed on 14 December .
Mars
0.533 Earths Polar radius 7006337620000000000 ♠ 3,376.2 ± 0.1 km 0.531 Earths Flattening 6997589000000000000 ♠ 0.00589 ± 0.00015 Surface area 7014144798500000000 ♠ 144,798,500 km 0.284 Earths Volume 7020163180000000000 ♠ 1.6318 × 10 km 0.151 Earths Mass 7023641710000000000 ♠ 6.4171 × 10 kg 0.107 Earths Mean density 7000393350000000000 ♠ 3.9335 ± 0.0004 g / cm3 Surface gravity 7000371100000000000 ♠ 3.711 m / s2 0.376 g Moment of inertia factor 6999366200000000000 ♠ 0.3662 ± 0.0017 Escape velocity 5.027 km / s Sidereal rotation period 7004886426848000000 ♠ 1.025957 d 24 37 22 Equatorial rotation velocity 868.22 km / h ( 241.17 m / s ) Axial tilt 25.19 ° to its orbital plane North pole right ascension 21 10 44 7000554458692594390 ♠ 317.68143 ° North pole declination 6999923043554855983 ♠ 52.88650 ° Albedo 0.170 ( geometric ) 0.25 ( Bond ) Surface temp . min mean max Kelvin 130 K 210 K 308 K Celsius − 143 ° C − 63 ° C 35 ° C Fahrenheit − 226 ° F − 82 ° F 95 ° F Apparent magnitude + 1.6 to − 3.0 Angular diameter 3.5 -- 25.1 '' Atmosphere Surface pressure 0.636 ( 0.4 -- 0.87 ) kPa 0.00628 atm Composition by volume 95.97 % carbon dioxide 1.93 % argon 1.89 % nitrogen 0.146 % oxygen 0.0557 % carbon monoxide
Modern history
The Space Age is a period encompassing the activities related to the Space Race , space exploration , space technology , and the cultural developments influenced by these events . The Space Age began with the development of several technologies that culminated with the launch of Sputnik 1 by the Soviet Union in October 1957 . This was the world 's first artificial satellite , orbiting the Earth in 98.1 minutes and weighing in at 83 kg . The launch of Sputnik 1 ushered a new era of political , scientific and technological achievements that became known as the Space Age . The Space Age was characterized by rapid development of new technology in a close race mostly between the United States and the Soviet Union . The Space Age brought the first human spaceflight during the Vostok programme and reached its peak with the Apollo program which captured the imagination of much of the world 's population . The landing of Apollo 11 was an event watched by over 500 million people around the world and is widely recognized as one of the defining moments of the 20th century . Since then and with the end of the space race due to the dissolution of the Soviet Union , public attention has largely moved to other areas .
Vredefort crater
The crater 's age is estimated to be 2.023 billion years ( ± 4 million years ) , which places it in the Paleoproterozoic Era . It is the second - oldest known crater on Earth , a little less than 300 million years younger than the Suavjärvi Crater in Russia . In comparison , it is about 10 % older than the Sudbury Basin impact ( at 1.849 billion years ) . A
Geologic time scale
Evidence from radiometric dating indicates that Earth is about 4.54 billion years old . The geology or deep time of Earth 's past has been organized into various units according to events which took place . Different spans of time on the GTS are usually marked by corresponding changes in the composition of strata which indicate major geological or paleontological events , such as mass extinctions . For example , the boundary between the Cretaceous period and the Paleogene period is defined by the Cretaceous -- Paleogene extinction event , which marked the demise of the non-avian dinosaurs and many other groups of life . Older time spans , which predate the reliable fossil record ( before the Proterozoic eon ) , are defined by their absolute age .
Moon landing
Russia 's Luna - Glob 1 is expected to be launched in 2018 . In 2007 the head of the Russian Space Agency announced plans to send cosmonauts to the Moon by 2025 and establish a permanent robotically operated base there in 2027 -- 2032 . In 2015 , Roscosmos stated that Russia plans to place a cosmonaut on the Moon by 2030 , leaving Mars to NASA . The purpose is to work jointly with NASA and avoid another Space Race .
Moon landing
For the program to succeed , its proponents would have to defeat criticism from politicians on the left , who wanted more money spent on social programs , and on those on the right , who favored a more military project . By emphasizing the scientific payoff and playing on fears of Soviet space dominance , Kennedy and Johnson managed to swing public opinion : by 1965 , 58 percent of Americans favored Apollo , up from 33 percent two years earlier . After Johnson became President in 1963 , his continuing defense of the program allowed it to succeed in 1969 , as Kennedy planned .
Maya calendar
The present era lunar synodic period is about 29.5305877 mean solar days or about 29 days 12 hours 44 minutes and 2 + / seconds . As a whole number , the number of days per lunation will be either 29 or 30 days , with the 30 - day intervals necessarily occurring slightly more frequently than the 29 - day intervals . The Maya wrote whether the lunar month was 29 or 30 days as two glyphs : a glyph for lunation length followed by either a glyph made up of a moon glyph over a bundle with a suffix of 9 for a 29 - day lunation or a moon glyph with a suffix of 10 for a 30 - day lunation . Since the Maya did n't use fractions , lunations were approximated by using the formula that there were 149 lunations completed in 4400 days , which yielded a rather short mean month of exactly / = 29 + / days = 29 days 12 hours 43 minutes and 29 + / seconds , or about 29.5302 days .
Alan Shepard
Shepard made his second space flight as Commander of Apollo 14 from January 31 to February 9 , 1971 . It was America 's third successful lunar landing mission . Shepard piloted the lunar module Antares to the most accurate landing of the entire Apollo program . He became the fifth and , at the age of 47 , the oldest man to walk on the moon , and the only one of the Mercury Seven astronauts to do so .
Observable universe
15.8 billion light - years This is obtained in the same way as the 13.8 - billion - light - year figure , but starting from an incorrect age of the universe that the popular press reported in mid-2006 . For an analysis of this claim and the paper that prompted it , see the following reference at the end of this article .
Grand Canyon
The major geologic exposures in the Grand Canyon range in age from the 2 - billion - year - old Vishnu Schist at the bottom of the Inner Gorge to the 230 - million - year - old Kaibab Limestone on the Rim . There is a gap of about a billion years between the 500 - million - year - old stratum and the level below it , which dates to about 1.5 billion years ago . This large unconformity indicates a long period for which no deposits are present .
February
Having only 28 days in common years , February is the only month of the year that can pass without a single full moon . Using Coordinated Universal Time as the basis for determining the date and time of a full moon , this last happened in 1999 and will next happen in 2018 . The same is true regarding a new moon : again using Coordinated Universal Time as the basis , this last happened in 2014 and will next happen in 2033 .
Plate tectonics
The discovery of radioactivity and its associated heating properties in 1895 prompted a re-examination of the apparent age of the Earth . This had previously been estimated by its cooling rate under the assumption that the Earth 's surface radiated like a black body . Those calculations had implied that , even if it started at red heat , the Earth would have dropped to its present temperature in a few tens of millions of years . Armed with the knowledge of a new heat source , scientists realized that the Earth would be much older , and that its core was still sufficiently hot to be liquid .
Jupiter
The observation of Jupiter dates back to at least the Babylonian astronomers of the 7th or 8th century BC . The ancient Chinese also observed the orbit of Suìxīng ( 歲星 ) and established their cycle of 12 earthly branches based on its approximate number of years ; the Chinese language still uses its name ( simplified as 岁 ) when referring to years of age . By the 4th century BC , these observations had developed into the Chinese zodiac , with each year associated with a Tai Sui star and god controlling the region of the heavens opposite Jupiter 's position in the night sky ; these beliefs survive in some Taoist religious practices and in the East Asian zodiac 's twelve animals , now often popularly assumed to be related to the arrival of the animals before Buddha . The Chinese historian Xi Zezong has claimed that Gan De , an ancient Chinese astronomer , discovered one of Jupiter 's moons in 362 BC with the unaided eye . If accurate , this would predate Galileo 's discovery by nearly two millennia . In his 2nd century work the Almagest , the Hellenistic astronomer Claudius Ptolemaeus constructed a geocentric planetary model based on deferents and epicycles to explain Jupiter 's motion relative to Earth , giving its orbital period around Earth as 4332.38 days , or 11.86 years . In 499 , Aryabhata , a mathematician -- astronomer from the classical age of Indian mathematics and astronomy , also used a geocentric model to estimate Jupiter 's period as 4332.2722 days , or 11.86 years .
Astronomical spectroscopy
In these equations , frequency is denoted by f ( \ displaystyle f ) and wavelength by λ ( \ displaystyle \ lambda ) . The larger the value of z , the more redshifted the light and the farther away the object is from the Earth . As of January 2013 , the largest galaxy redshift of z ~ 12 was found using the Hubble Ultra-Deep Field , corresponding to an age of over 13 billion years ( the universe is approximately 13.82 billion years old ) .
Coordinated Universal Time
Just as adding a leap day every four years does not mean the year is getting longer by one day every four years , the insertion of a leap second every 800 days does not indicate that the mean solar day is getting longer by a second every 800 days . It will take about 50,000 years for a mean solar day to lengthen by one second ( at a rate of 2 ms / cy , where cy means century ) . This rate fluctuates within the range of 1.7 -- 2.3 ms / cy . While the rate due to tidal friction alone is about 2.3 ms / cy , the uplift of Canada and Scandinavia by several metres since the last Ice Age has temporarily reduced this to 1.7 ms / cy over the last 2,700 years . The correct reason for leap seconds , then , is not the current difference between actual and nominal LOD , but rather the accumulation of this difference over a period of time : Near the end of the 20th century , this difference was about 1 / 800 of a second per day ; therefore , after about 800 days , it accumulated to 1 second ( and a leap second was then added ) .
Reactions to On the Origin of Species
In June 1861 Thomson asked Phillips how geologists felt about Darwin 's `` prodigious durations for geological epochs '' . and mentioned his own preliminary calculation that the Sun was 20 million years old , with the Earth at most 200 to 1,000 million years old . Phillips discussed his own published view that stratified rocks went back 96 million years , and dismissed Darwin 's original estimate that the Weald had taken 300 million years to erode . In September 1861 Thomson produced a paper `` On the age of the Sun 's heat '' which estimated that the Sun was between 100 and 500 million years old , and in 1862 he used assumptions on the rate of cooling from a molten condition to estimate the age of the Earth at 98 million years . The dispute continued for the rest of Darwin 's life .