vania-janet/multiturn-rag-retrieval-data huggingface dataset:
Sundial
In its simplest form , the style is a thin slit that allows the sun 's rays to fall on the hour - lines of an equatorial ring . As usual , the style is aligned with the Earth 's axis ; to do this , the user may orient the dial towards true North and suspend the ring dial vertically from the appropriate point on the meridian ring . Such dials may be made self - aligning with the addition of a more complicated central bar , instead of a simple slit - style . These bars are sometimes an addition to a set of Gemma 's rings . This bar could pivot about its end points and held a perforated slider that was positioned to the month and day according to a scale scribed on the bar . The time was determined by rotating the bar towards the sun so that the light shining through the hole fell on the equatorial ring . This forced the user to rotate the instrument , which had the effect of aligning the instrument 's vertical ring with the meridian .
Color television
Similar concepts were common through the 1940s and 50s , differing primarily in the way they re-combined the colors generated by the three guns . The Geer tube was similar to Baird 's concept , but used small pyramids with the phosphors deposited on their outside faces , instead of Baird 's 3D patterning on a flat surface . The Penetron used three layers of phosphor on top of each other and increased the power of the beam to reach the upper layers when drawing those colors . The Chromatron used a set of focusing wires to select the colored phosphors arranged in vertical stripes on the tube . FCC
Triangle
The shape of the triangle is determined by the lengths of the sides . Therefore , the area can also be derived from the lengths of the sides . By Heron 's formula :
Reuleaux triangle
The shape was first isolated in crystal form in 2014 as Reuleaux triangle disks . Basic bismuth nitrate disks with the Reuleaux triangle shape were formed from the hydrolysis and precipitation of bismuth nitrate in an ethanol -- water system in the presence of 2 , 3 - bis ( 2 - pyridyl ) pyrazine .
Moon landing
The Moon landing required development of the large Saturn V launch vehicle , which achieved a perfect record of zero catastrophic failures or launch vehicle - caused mission failures , in thirteen launches .
Thunderstorm
Waterspouts have similar characteristics as tornadoes , characterized by a spiraling funnel - shaped wind current that form over bodies of water , connecting to large cumulonimbus clouds . Waterspouts are generally classified as forms of tornadoes , or more specifically , non-supercelled tornadoes that develop over large bodies of water . These spiralling columns of air are frequently developed within tropical areas close to the equator , but are less common within areas of high latitude .
Wetland
Wetlands vary widely due to local and regional differences in topography , hydrology , vegetation , and other factors , including human involvement . Wetlands can be divided into two main classes . They are tidal and non-tidal areas .
Star formation
Accretion of material onto the protostar continues partially from the newly formed circumstellar disc . When the density and temperature are high enough , deuterium fusion begins , and the outward pressure of the resultant radiation slows ( but does not stop ) the collapse . Material comprising the cloud continues to `` rain '' onto the protostar . In this stage bipolar jets are produced called Herbig - Haro objects . This is probably the means by which excess angular momentum of the infalling material is expelled , allowing the star to continue to form . Star
Reuleaux triangle
The constant width of these shapes allows their use as coins that can be used in coin - operated machines . For instance , the United Kingdom has made 20 - pence and 50 - pence coins in the shape of a Reuleaux heptagon . The Canadian Loonie dollar coin uses another Reuleaux polygon with 11 sides .
Mars
It is thought that , during the Solar System 's formation , Mars was created as the result of a stochastic process of run - away accretion of material from the protoplanetary disk that orbited the Sun . Mars has many distinctive chemical features caused by its position in the Solar System . Elements with comparatively low boiling points , such as chlorine , phosphorus , and sulphur , are much more common on Mars than Earth ; these elements were probably pushed outward by the young Sun 's energetic solar wind .
Helium
Helium - 3 is present on Earth only in trace amounts . Most of it has been present since Earth 's formation , though some falls to Earth trapped in cosmic dust . Trace amounts are also produced by the beta decay of tritium . Rocks from the Earth 's crust have isotope ratios varying by as much as a factor of ten , and these ratios can be used to investigate the origin of rocks and the composition of the Earth 's mantle . He is much more abundant in stars as a product of nuclear fusion . Thus in the interstellar medium , the proportion of He to He is about 100 times higher than on Earth . Extraplanetary material , such as lunar and asteroid regolith , have trace amounts of helium - 3 from being bombarded by solar winds . The Moon 's surface contains helium - 3 at concentrations on the order of 10 ppb , much higher than the approximately 5 ppt found in the Earth 's atmosphere . A number of people , starting with Gerald Kulcinski in 1986 , have proposed to explore the moon , mine lunar regolith , and use the helium - 3 for fusion .
Wikipedia:Citing sources
Brown , Rebecca ( 2006 ) . `` Size of the Moon '' , Scientific American , 51 ( 78 ) . Miller , Edward ( 2005 ) . The Sun . Academic Press .
Wonders of the Solar System
The third episode looks at the atmosphere of the planets and moons of the Solar System , with Earth , Mars , and Venus being the main focus . The episode starts with Cox travelling to South Africa and taking a journey in an English Electric Lightning up to an altitude of 18 kilometres where the `` thinness and fragility '' of the atmosphere could be observed in the middle of the day . This is then contrasted with the planet - wide consequences of Mercury 's depleted , and Venus ' broiling greenhouse atmospheres . Later , the dunal morphology of the Namib Desert is compared to what is known of the surface and depleted atmosphere of Mars , and is used to give an explanation of how the Earth maintains its temperature . Cox then explains how the damaging effect of the sun 's solar wind is deflected by the Earth 's magnetosphere . Next , he discusses the transformative effect of weather on a planet 's surface , such as the global dust - storms on Mars or the electrical - storms of Jupiter . The episode continues with an in - depth comparison of Saturn 's largest moon , Titan , using data gained from the Huygens probe 's January 2005 descent down to the frigid methane surface of the moon . It ends with Cox comparing Earth 's hydrological cycle with Titan 's methanological one .
Lunar distance (astronomy)
Through the action of tidal forces , angular momentum is slowly being transferred from Earth 's rotation to the Moon 's orbit . The result is that Earth 's rate of spin is imperceptibly decreasing ( at a rate of 7000229999999999999 ♠ 2.3 milliseconds / century ) , and the lunar orbit is gradually expanding . The current rate of recession is 7000380500000000000 ♠ 3.805 ± 0.004 cm per year . However , it is believed that this rate has recently increased , as a rate of 6991120417206325883 ♠ 3.8 cm / year would imply that the Moon is only 1.5 billion years old , whereas scientific consensus assumes an age of ~ 4 billion years . It is also believed that this anomalously high rate of recession may continue to accelerate .
Moon landing
Controlling the location of impact for spent lunar orbiters can have scientific value . For example , in 1999 the NASA Lunar Prospector orbiter was deliberately targeted to impact a permanently shadowed area of Shoemaker Crater near the lunar south pole . It was hoped that energy from the impact would vaporize suspected shadowed ice deposits in the crater and liberate a water vapor plume that would be detectable from Earth . No such plume was observed . However , a small vial of ashes from the body of pioneer lunar scientist Eugene Shoemaker was delivered by the Lunar Prospector to the crater named in his honor -- currently the only human remains on the Moon .
Global Positioning System
The measured ranges , called pseudoranges , contain clock errors . In a simplified idealization in which the ranges are synchronized , these true ranges represent the radii of spheres , each centered on one of the transmitting satellites . The solution for the position of the receiver is then at the intersection of the surfaces of three of these spheres . If more than the minimum number of ranges is available , a near intersection of more than three sphere surfaces could be found via , e.g. least squares . Hyperboloids
Time
A sundial uses a gnomon to cast a shadow on a set of markings calibrated to the hour . The position of the shadow marks the hour in local time . The idea to separate the day into smaller parts is credited to Egyptians because of their sundials , which operated on a duodecimal system . The importance of the number 12 is due the number of lunar cycles in a year and the number of stars used to count the passage of night .
Cardinal direction
A line ( here it is a great circle on the celestial sphere ) drawn from the center of the disk to the North celestial pole will intersect the body 's limb at the North point . Similarly , a line from the center to the South celestial pole will define the South point by its intersection with the limb . The points at right angles to the North and South points are the East and West points . The North point will then be the point on the limb that is closest to the North celestial pole .
River delta
Researchers have found a number of examples of deltas that formed in Martian lakes . Finding deltas is a major sign that Mars once had large amounts of water . Deltas have been found over a wide geographical range . Below are pictures of a few .
Mars
Landforms visible on Mars strongly suggest that liquid water has existed on the planet 's surface . Huge linear swathes of scoured ground , known as outflow channels , cut across the surface in about 25 places . These are thought to be a record of erosion caused by the catastrophic release of water from subsurface aquifers , though some of these structures have been hypothesized to result from the action of glaciers or lava . One of the larger examples , Ma'adim Vallis is 700 km ( 430 mi ) long , much greater than the Grand Canyon , with a width of 20 km ( 12 mi ) and a depth of 2 km ( 1.2 mi ) in places . It is thought to have been carved by flowing water early in Mars 's history . The youngest of these channels are thought to have formed as recently as only a few million years ago . Elsewhere , particularly on the oldest areas of the Martian surface , finer - scale , dendritic networks of valleys are spread across significant proportions of the landscape . Features of these valleys and their distribution strongly imply that they were carved by runoff resulting from precipitation in early Mars history . Subsurface water flow and groundwater sapping may play important subsidiary roles in some networks , but precipitation was probably the root cause of the incision in almost all cases .
Lunar distance (astronomy)
An experiment was conducted in 1957 at the U.S. Naval Research Laboratory that used the echo from radar signals to determine the Earth - Moon distance . Radar pulses lasting 6994200000000000000 ♠ 2 μs were broadcast from a 7001152400000000000 ♠ 50 ft diameter radio dish . After the radio waves echoed off the surface of the Moon , the return signal was detected and the delay time measured . From that measurement , the distance could be calculated . In practice , however , the signal - to - noise ratio was so low that an accurate measurement could not be reliably produced .
Types of volcanic eruptions
Hawaiian eruptions are responsible for several unique volcanological objects . Small volcanic particles are carried and formed by the wind , chilling quickly into teardrop - shaped glassy fragments known as Pele 's tears ( after Pele , the Hawaiian volcano deity ) . During especially high winds these chunks may even take the form of long drawn - out strands , known as Pele 's hair . Sometimes basalt aerates into reticulite , the lowest density rock type on earth .
Global Positioning System
The solution space ( x , y , z , b ) can be seen as a four - dimensional geometric space . In that case each of the equations describes a spherical cone , with the cusp located at the satellite , and the base a sphere around the satellite . The receiver is at the intersection of four or more of such cones .
Jupiter
The magnetosphere of Jupiter is responsible for intense episodes of radio emission from the planet 's polar regions . Volcanic activity on Jupiter 's moon Io ( see below ) injects gas into Jupiter 's magnetosphere , producing a torus of particles about the planet . As Io moves through this torus , the interaction generates Alfvén waves that carry ionized matter into the polar regions of Jupiter . As a result , radio waves are generated through a cyclotron maser mechanism , and the energy is transmitted out along a cone - shaped surface . When Earth intersects this cone , the radio emissions from Jupiter can exceed the solar radio output .
Kuiper belt
The Kuiper belt is thought to consist of planetesimals , fragments from the original protoplanetary disc around the Sun that failed to fully coalesce into planets and instead formed into smaller bodies , the largest less than 3,000 kilometres ( 1,900 mi ) in diameter . Studies of the crater counts on Pluto and Charon revealed a scarcity of small craters suggesting that such objects formed directly as sizeable objects in the range of tens of kilometers in diameter rather than being accreted from much smaller , roughly kilometer scale bodies . Hypothetical mechanisms for the formation of these larger bodies include the gravitational collapse of clouds of pebbles concentrated between eddies in a turbulent protoplanetary disk or in streaming instabilities . These collapsing clouds may fragment , forming binaries .
Main sequence
Main - sequence stars employ two types of hydrogen fusion processes , and the rate of energy generation from each type depends on the temperature in the core region . Astronomers divide the main sequence into upper and lower parts , based on which of the two is the dominant fusion process . In the lower main sequence , energy is primarily generated as the result of the proton - proton chain , which directly fuses hydrogen together in a series of stages to produce helium . Stars in the upper main sequence have sufficiently high core temperatures to efficiently use the CNO cycle . ( See the chart . ) This process uses atoms of carbon , nitrogen and oxygen as intermediaries in the process of fusing hydrogen into helium .
Space Race
Focused by the commitment to a Moon landing , in January 1962 the US announced Project Gemini , a two - man spacecraft that would support the later three - man Apollo by developing the key spaceflight technologies of space rendezvous and docking of two craft , flight durations of sufficient length to simulate going to the Moon and back , and extra-vehicular activity to accomplish useful work outside the spacecraft .
Astronomical spectroscopy
Using this information the shape of the Milky Way has been determined to be a spiral galaxy , though the exact number and position of the spiral arms is the subject of ongoing research .
Moon landing
In order to go to the Moon , a spacecraft must first leave the gravity well of the Earth . The only practical way of accomplishing this currently is with a rocket . Unlike other airborne vehicles such as balloons or jets , a rocket is the only known form of propulsion which can continue to increase its speed at high altitudes in the vacuum outside the Earth 's atmosphere .
River delta
The bottomset beds are created from the lightest suspended particles that settle farthest away from the active delta front , as the river flow diminishes into the standing body of water and loses energy . This suspended load is deposited by sediment gravity flow , creating a turbidite . These beds are laid down in horizontal layers and consist of the finest grain sizes . The foreset beds in turn are deposited in inclined layers over the bottomset beds as the active lobe advances . Foreset beds form the greater part of the bulk of a delta , ( and also occur on the lee side of sand dunes ) . The sediment particles within foreset beds consist of larger and more variable sizes , and constitute the bed load that the river moves downstream by rolling and bouncing along the channel bottom . When the bed load reaches the edge of the delta front , it rolls over the edge , and is deposited in steeply dipping layers over the top of the existing bottomset beds . Under water , the slope of the outermost edge of the delta is created at the angle of repose of these sediments . As the foresets accumulate and advance , subaqueous landslides occur and readjust overall slope stability . The foreset slope , thus created and maintained , extends the delta lobe outward . In cross section , foresets typically lie in angled , parallel bands , and indicate stages and seasonal variations during the creation of the delta . The topset beds of an advancing delta are deposited in turn over the previously laid foresets , truncating or covering them . Topsets are nearly horizontal layers of smaller - sized sediment deposited on the top of the delta and form an extension of the landward alluvial plain . As the river channels meander laterally across the top of the delta , the river is lengthened and its gradient is reduced , causing the suspended load to settle out in nearly horizontal beds over the delta 's top . Topset beds are subdivided into two regions : the upper delta plain and the lower delta plain . The upper delta plain is unaffected by the tide , while the boundary with the lower delta plain is defined by the upper limit of tidal influence .
Moon landing
NASA then collaborated with the United States Army 's Ballistic Missile Agency to fly two extremely small cone - shaped probes on the Juno ICBM , carrying only photocells which would be triggered by the light of the Moon and a lunar radiation environment experiment using a Geiger - Müller tube detector . The first of these reached an altitude of only around 100,000 kilometres ( 62,000 mi ) , serendipitously gathering data that established the presence of the Van Allen radiation belts before reentering Earth 's atmosphere . The second passed by the Moon at a distance of more than 60,000 kilometres ( 37,000 mi ) , twice as far as planned and too far away to trigger either of the on - board scientific instruments , yet still becoming the first U.S. spacecraft to reach a solar orbit .
Halley's Comet
The Giotto and Vega missions gave planetary scientists their first view of Halley 's surface and structure . Like all comets , as Halley nears the Sun , its volatile compounds ( those with low boiling points , such as water , carbon monoxide , carbon dioxide and other ices ) begin to sublime from the surface of its nucleus . This causes the comet to develop a coma , or atmosphere , up to 100,000 km across . Evaporation of this dirty ice releases dust particles , which travel with the gas away from the nucleus . Gas molecules in the coma absorb solar light and then re-radiate it at different wavelengths , a phenomenon known as fluorescence , whereas dust particles scatter the solar light . Both processes are responsible for making the coma visible . As a fraction of the gas molecules in the coma are ionized by the solar ultraviolet radiation , pressure from the solar wind , a stream of charged particles emitted by the Sun , pulls the coma 's ions out into a long tail , which may extend more than 100 million kilometers into space . Changes in the flow of the solar wind can cause disconnection events , in which the tail completely breaks off from the nucleus .
Cumulus cloud
Cirrocumulus clouds form in patches and can not cast shadows . They commonly appear in regular , rippling patterns or in rows of clouds with clear areas between . Cirrocumulus are , like other members of the cumuliform and stratocumuliform categories , formed via convective processes . Significant growth of these patches indicates high - altitude instability and can signal the approach of poorer weather . The ice crystals in the bottoms of cirrocumulus clouds tend to be in the form of hexagonal cylinders . They are not solid , but instead tend to have stepped funnels coming in from the ends . Towards the top of the cloud , these crystals have a tendency to clump together . These clouds do not last long , and they tend to change into cirrus because as the water vapor continues to deposit on the ice crystals , they eventually begin to fall , destroying the upward convection . The cloud then dissipates into cirrus . Cirrocumulus clouds come in four species which are common to all three genus - types that have limited - convective or stratocumuliform characteristics : stratiformis , lenticularis , castellanus , and floccus . They are iridescent when the constituent supercooled water droplets are all about the same size .
Rainbow
The sky inside a primary rainbow is brighter than the sky outside of the bow . This is because each raindrop is a sphere and it scatters light over an entire circular disc in the sky . The radius of the disc depends on the wavelength of light , with red light being scattered over a larger angle than blue light . Over most of the disc , scattered light at all wavelengths overlaps , resulting in white light which brightens the sky . At the edge , the wavelength dependence of the scattering gives rise to the rainbow .
Magnetosphere of Jupiter
The bulk of Jupiter 's magnetic field , like Earth 's , is generated by an internal dynamo supported by the circulation of a conducting fluid in its outer core . But whereas Earth 's core is made of molten iron and nickel , Jupiter 's is composed of metallic hydrogen . As with Earth 's , Jupiter 's magnetic field is mostly a dipole , with north and south magnetic poles at the ends of a single magnetic axis . However , on Jupiter the north pole of the dipole is located in the planet 's northern hemisphere and the south pole of the dipole lies in its southern hemisphere , opposite to the Earth , whose north pole lies in the southern hemisphere and south pole lies in the northern hemisphere . Jupiter 's field also has quadrupole , octupole and higher components , though they are less than one tenth as strong as the dipole component .
Little Red Riding Hood
Folklorists and cultural anthropologists , such as P. Saintyves and Edward Burnett Tylor , saw `` Little Red Riding Hood '' in terms of solar myths and other naturally occurring cycles . Her red hood could represent the bright sun which is ultimately swallowed by the terrible night ( the wolf ) , and the variations in which she is cut out of the wolf 's belly represent the dawn . In this interpretation , there is a connection between the wolf of this tale and Sköll , the wolf in Norse mythology that will swallow the personified Sun at Ragnarök , or Fenrir . Alternatively , the tale could be about the season of spring or the month of May , escaping the winter . Red