rajpurkar/squad huggingface dataset:
Title: Neptune

There do exist orbits within these empty regions where objects can survive for the age of the Solar System. These resonances occur when Neptune's orbital period is a precise fraction of that of the object, such as 1:2, or 3:4. If, say, an object orbits the Sun once for every two Neptune orbits, it will only complete half an orbit by the time Neptune returns to its original position. The most heavily populated resonance in the Kuiper belt, with over 200 known objects, is the 2:3 resonance. Objects in this resonance complete 2 orbits for every 3 of Neptune, and are known as plutinos because the largest of the known Kuiper belt objects, Pluto, is among them. Although Pluto crosses Neptune's orbit regularly, the 2:3 resonance ensures they can never collide. The 3:4, 3:5, 4:7 and 2:5 resonances are less populated.

Question: What is the fraction of the most heavily populated resonance in the Kuiper belt? 
Answer: 2:3 resonance

Question: What is the best known, and largest, object in the Kuiper belt?
Answer: Pluto

Question: How many known objects is in the most populated resonance of the Kuiper belt?
Answer: 200

Question: What is the resonance of Pluto in the Kuiper belt?
Answer: 2:3

Question: Which resonances are less populated in the Kuiper belt?
Answer: 3:4, 3:5, 4:7 and 2:5
Title: Neptune

Neptune has a number of known trojan objects occupying both the Sun–Neptune L4 and L5 Lagrangian points—gravitationally stable regions leading and trailing Neptune in its orbit, respectively. Neptune trojans can be viewed as being in a 1:1 resonance with Neptune. Some Neptune trojans are remarkably stable in their orbits, and are likely to have formed alongside Neptune rather than being captured. The first and so far only object identified as associated with Neptune's trailing L5 Lagrangian point is 2008 LC18. Neptune also has a temporary quasi-satellite, (309239) 2007 RW10. The object has been a quasi-satellite of Neptune for about 12,500 years and it will remain in that dynamical state for another 12,500 years.

Question: What is the resonance of Neptune trojans?
Answer: 1:1

Question: Where did most Neptune trojans form?
Answer: alongside Neptune

Question: What is the only object identified with Neptune's trailing L5 Lagrangian point?
Answer: 2008 LC18

Question: What is Neptune's temporary quasi-satellite named?
Answer: (309239) 2007 RW10

Question: How long has Neptune's quasi-satellite been with Neptune? 
Answer: 12,500 years
Title: Neptune

The formation of the ice giants, Neptune and Uranus, has proven difficult to model precisely. Current models suggest that the matter density in the outer regions of the Solar System was too low to account for the formation of such large bodies from the traditionally accepted method of core accretion, and various hypotheses have been advanced to explain their formation. One is that the ice giants were not formed by core accretion but from instabilities within the original protoplanetary disc and later had their atmospheres blasted away by radiation from a nearby massive OB star.

Question: What could have blasted Neptune and Uranus's atmosphere with radiation, aiding in creation? 
Answer: nearby massive OB star

Question: What is too low to account for the formation of Neptune?
Answer: matter density

Question: If Neptune was formed from instabilities within the original protoplanetary disc, what was it not formed by?
Answer: core accretion
Title: Neptune

An alternative concept is that they formed closer to the Sun, where the matter density was higher, and then subsequently migrated to their current orbits after the removal of the gaseous protoplanetary disc. This hypothesis of migration after formation is favoured, due to its ability to better explain the occupancy of the populations of small objects observed in the trans-Neptunian region. The current most widely accepted explanation of the details of this hypothesis is known as the Nice model, which explores the effect of a migrating Neptune and the other giant planets on the structure of the Kuiper belt.

Question: If Neptune formed closer to the sun, what is the matter density?
Answer: higher

Question: If Neptune formed closer to the sun, what caused it to migrate to it's current orbit?
Answer: removal of the gaseous protoplanetary disc

Question: What is the most widely accepted explanation of Neptune's formation called?
Answer: the Nice model

Question: What does The Nice model consider effected the migration of Neptune?
Answer: Kuiper belt.
Title: Neptune

Neptune has 14 known moons. Triton is the largest Neptunian moon, comprising more than 99.5% of the mass in orbit around Neptune,[e] and it is the only one massive enough to be spheroidal. Triton was discovered by William Lassell just 17 days after the discovery of Neptune itself. Unlike all other large planetary moons in the Solar System, Triton has a retrograde orbit, indicating that it was captured rather than forming in place; it was probably once a dwarf planet in the Kuiper belt. It is close enough to Neptune to be locked into a synchronous rotation, and it is slowly spiralling inward because of tidal acceleration. It will eventually be torn apart, in about 3.6 billion years, when it reaches the Roche limit. In 1989, Triton was the coldest object that had yet been measured in the Solar System, with estimated temperatures of 38 K (−235 °C).

Question: How many moons does Neptune have?
Answer: 14

Question: What is Neptune's largest moon?
Answer: Triton

Question: Who discovered Triton? 
Answer: William Lassell

Question: What orbit does Triton have around Neptune? 
Answer: retrograde orbit

Question: What does Triton's orbit suggest about it's relation to Neptune?
Answer: that it was captured
Title: Neptune

From July to September 1989, Voyager 2 discovered six moons of Neptune. Of these, the irregularly shaped Proteus is notable for being as large as a body of its density can be without being pulled into a spherical shape by its own gravity. Although the second-most-massive Neptunian moon, it is only 0.25% the mass of Triton. Neptune's innermost four moons—Naiad, Thalassa, Despina and Galatea—orbit close enough to be within Neptune's rings. The next-farthest out, Larissa, was originally discovered in 1981 when it had occulted a star. This occultation had been attributed to ring arcs, but when Voyager 2 observed Neptune in 1989, Larissa was found to have caused it. Five new irregular moons discovered between 2002 and 2003 were announced in 2004. A new moon and the smallest yet, S/2004 N 1, was found in 2013. Because Neptune was the Roman god of the sea, Neptune's moons have been named after lesser sea gods.

Question: What discovered six moons of Neptune in 1989?
Answer: Voyager 2

Question: What is the second most massive Neptunian moon? 
Answer: Proteus

Question: What is notable about the moon Proteus?
Answer: irregularly shaped

Question: Which are Neptune's four innermost moons?
Answer: Naiad, Thalassa, Despina and Galatea

Question: When was Neptune's moon Larissa discovered? 
Answer: 1981
Title: Neptune

Because of the distance of Neptune from Earth, its angular diameter only ranges from 2.2 to 2.4 arcseconds, the smallest of the Solar System planets. Its small apparent size makes it challenging to study it visually. Most telescopic data was fairly limited until the advent of Hubble Space Telescope (HST) and large ground-based telescopes with adaptive optics (AO). The first scientifically useful observation of Neptune from ground-based telescopes using adaptive optics, was commenced in 1997 from Hawaii. Neptune is currently entering its spring and summer season and has been shown to be heating up, with increased atmospheric activity and brightness as a consequence. Combined with technological advancements, ground-based telescopes with adaptive optics are recording increasingly more detailed images of this Outer Planet. Both the HST and AO telescopes on Earth has made many new discoveries within the Solar System since the mid-1990s, with a large increase in the number of known satellites and moons around the Outer Planets for example. In 2004 and 2005, five new small satellites of Neptune with diameters between 38 and 61 kilometres were discovered.

Question: What is Neptune's angular diameter range?
Answer: 2.2 to 2.4 arcseconds

Question: The advent of what telescope made it easier to study Neptune?
Answer: Hubble Space Telescope

Question: When was the first useful observation of Neptune from the ground?
Answer: 1997

Question: What seasons are Neptune currently entering?
Answer: spring and summer

Question: What was discovered around Neptune in 2004 and 2005?
Answer: five new small satellites
Title: Neptune

Voyager 2 is the only spacecraft that has visited Neptune. The spacecraft's closest approach to the planet occurred on 25 August 1989. Because this was the last major planet the spacecraft could visit, it was decided to make a close flyby of the moon Triton, regardless of the consequences to the trajectory, similarly to what was done for Voyager 1's encounter with Saturn and its moon Titan. The images relayed back to Earth from Voyager 2 became the basis of a 1989 PBS all-night program, Neptune All Night.

Question: What is the only spacecraft to visit Neptune?
Answer: Voyager 2

Question: When did a spacecraft get closest to Neptune?
Answer: 25 August 1989

Question: What near Neptune did a spacecraft visit dangerously close?
Answer: Triton

Question: What program aired on PBS about Neptune?
Answer: Neptune All Night
Title: Neptune

After the Voyager 2 flyby mission, the next step in scientific exploration of the Neptunian system, is considered to be a Flagship orbital mission. Such a hypothetical mission is envisioned to be possible at in the late 2020s or early 2030s. However, there have been a couple of discussions to launch Neptune missions sooner. In 2003, there was a proposal in NASA's "Vision Missions Studies" for a "Neptune Orbiter with Probes" mission that does Cassini-level science. Another, more recent proposal was for Argo, a flyby spacecraft to be launched in 2019, that would visit Jupiter, Saturn, Neptune, and a Kuiper belt object. The focus would be on Neptune and its largest moon Triton to be investigated around 2029. The proposed New Horizons 2 mission (which was later scrapped) might also have done a close flyby of the Neptunian system.

Question: When is the next hypothetical mission to Neptune?
Answer: late 2020s

Question: What about Neptune did NASA propose in 2003 in their "Vision Missions Studies"?
Answer: Neptune Orbiter with Probes

Question: When will Argo be launched?
Answer: 2019

Question: What will Argo visit?
Answer: Jupiter, Saturn, Neptune, and a Kuiper belt object

Question: When can we expect Argo to visit Triton?
Answer: 2029
Title: Railway_electrification_system

A railway electrification system supplies electric power to railway trains and trams without an on-board prime mover or local fuel supply. Electrification has many advantages but requires significant capital expenditure. Selection of an electrification system is based on economics of energy supply, maintenance, and capital cost compared to the revenue obtained for freight and passenger traffic. Different systems are used for urban and intercity areas; some electric locomotives can switch to different supply voltages to allow flexibility in operation.

Question: What is of the factors the capital cost of electrification system depends on?
Answer: maintenance

Question: How do some locomotives function in order to be more flexible in operation?
Answer: can switch to different supply voltages

Question: What are two types of revenue obtained through railway transportation?
Answer: freight and passenger traffic

Question: What is the main disadvantage of railway electrification?
Answer: significant capital expenditure
Title: Railway_electrification_system

Electric railways use electric locomotives to haul passengers or freight in separate cars or electric multiple units, passenger cars with their own motors. Electricity is typically generated in large and relatively efficient generating stations, transmitted to the railway network and distributed to the trains. Some electric railways have their own dedicated generating stations and transmission lines but most purchase power from an electric utility. The railway usually provides its own distribution lines, switches and transformers.

Question: What is used to haul passengers cars?
Answer: electric locomotives

Question: How is electricity being generated for electric locomotives?
Answer: generating stations

Question: What entity provides distribution lines, switches and transformers?
Answer: railway
Title: Railway_electrification_system

In comparison to the principal alternative, the diesel engine, electric railways offer substantially better energy efficiency, lower emissions and lower operating costs. Electric locomotives are usually quieter, more powerful, and more responsive and reliable than diesels. They have no local emissions, an important advantage in tunnels and urban areas. Some electric traction systems provide regenerative braking that turns the train's kinetic energy back into electricity and returns it to the supply system to be used by other trains or the general utility grid. While diesel locomotives burn petroleum, electricity is generated from diverse sources including many that do not produce carbon dioxide such as nuclear power and renewable forms including hydroelectric, geothermal, wind and solar.

Question: What is the principal alternative to electric railways?
Answer: diesel engine

Question: What locomotives are usually more reliable?
Answer: Electric locomotives

Question: What do some electric traction systems provide?
Answer: regenerative braking

Question: What type of fuel do diesel locomotives use?
Answer: petroleum

Question: What is one of the sources electricity is being generated from?
Answer: geothermal
Title: Railway_electrification_system

Disadvantages of electric traction include high capital costs that may be uneconomic on lightly trafficked routes; a relative lack of flexibility since electric trains need electrified tracks or onboard supercapacitors and charging infrastructure at stations; and a vulnerability to power interruptions. Different regions may use different supply voltages and frequencies, complicating through service. The limited clearances available under catenaries may preclude efficient double-stack container service. The lethal voltages on contact wires and third rails are a safety hazard to track workers, passengers and trespassers. Overhead wires are safer than third rails, but they are often considered unsightly.

Question: What is a safety hazard to track workers?
Answer: voltages on contact wires

Question: What issue can complicate electric railway service?
Answer: different supply voltages and frequencies,

Question: What is a safer alternative to third rails?
Answer: Overhead wires

Question: Why overhead wires are not being widely used?
Answer: considered unsightly.
Title: Railway_electrification_system

Railways must operate at variable speeds. Until the mid 1980s this was only practical with the brush-type DC motor, although such DC can be supplied from an AC catenary via on-board electric power conversion. Since such conversion was not well developed in the late 19th century and early 20th century, most early electrified railways used DC and many still do, particularly rapid transit (subways) and trams. Speed was controlled by connecting the traction motors in various series-parallel combinations, by varying the traction motors' fields, and by inserting and removing starting resistances to limit motor current.

Question: What is speed limit for railways?
Answer: variable speeds

Question: Why is DC motor being used more than AC type?
Answer: conversion was not well developed

Question: What are two types of railway transportation still use DC motor?
Answer: rapid transit (subways) and trams
Title: Railway_electrification_system

Motors have very little room for electrical insulation so they generally have low voltage ratings. Because transformers (prior to the development of power electronics) cannot step down DC voltages, trains were supplied with a relatively low DC voltage that the motors can use directly. The most common DC voltages are listed in the previous section. Third (and fourth) rail systems almost always use voltages below 1 kV for safety reasons while overhead wires usually use higher voltages for efficiency. ("Low" voltage is relative; even 600 V can be instantly lethal when touched.)

Question: Why do motors have little space for insulation?
Answer: low voltage ratings

Question: Why 1kV voltage is almost always used by rail systems?
Answer: safety reasons

Question: What is most common volatage range used by railway system?
Answer: below 1 kV

Question: Which system uses higher voltages?
Answer: overhead wires

Question: Is "low" voltage used by trains safe for people?
Answer: lethal
Title: Railway_electrification_system

There has, however, been interest among railroad operators in returning to DC use at higher voltages than previously used. At the same voltage, DC often has less loss than AC, and for this reason high-voltage direct current is already used on some bulk power transmission lines. DC avoids the electromagnetic radiation inherent with AC, and on a railway this also reduces interference with signalling and communications and mitigates hypothetical EMF risks. DC also avoids the power factor problems of AC. Of particular interest to railroading is that DC can supply constant power with a single ungrounded wire. Constant power with AC requires three-phase transmission with at least two ungrounded wires. Another important consideration is that mains-frequency 3-phase AC must be carefully planned to avoid unbalanced phase loads. Parts of the system are supplied from different phases on the assumption that the total loads of the 3 phases will even out. At the phase break points between regions supplied from different phases, long insulated supply breaks are required to avoid them being shorted by rolling stock using more than one pantograph at a time. A few railroads have tried 3-phase but its substantial complexity has made single-phase standard practice despite the interruption in power flow that occurs twice every cycle. An experimental 6 kV DC railway was built in the Soviet Union.

Question: What type of electric power garantees lesser loss?
Answer: DC

Question: Which type of supply for electric motors creates electromagnetic radiation?
Answer: AC

Question: Which type of power does require three-phase transmission?
Answer: AC

Question: What can electromagnetic radiation interfere with?
Answer: signalling and communications

Question: Where was an experimental 6kV DC railway built?
Answer: the Soviet Union
Title: Railway_electrification_system

1,500 V DC is used in the Netherlands, Japan, Republic Of Indonesia, Hong Kong (parts), Republic of Ireland, Australia (parts), India (around the Mumbai area alone, has been converted to 25 kV AC like the rest of India), France (also using 25 kV 50 Hz AC), New Zealand (Wellington) and the United States (Chicago area on the Metra Electric district and the South Shore Line interurban line). In Slovakia, there are two narrow-gauge lines in the High Tatras (one a cog railway). In Portugal, it is used in the Cascais Line and in Denmark on the suburban S-train system.

Question: What is most common voltage for DC supply?
Answer: 1,500 V

Question: How many narrow-gauge lines in Slovakia?
Answer: two

Question: What railway line is DC being used in Portugal?
Answer: the Cascais Line

Question: Where in India line has been converted to AC?
Answer: Mumbai area
Title: Railway_electrification_system

3 kV DC is used in Belgium, Italy, Spain, Poland, the northern Czech Republic, Slovakia, Slovenia, South Africa, Chile, and former Soviet Union countries (also using 25 kV 50 Hz AC). It was formerly used by the Milwaukee Road from Harlowton, Montana to Seattle-Tacoma, across the Continental Divide and including extensive branch and loop lines in Montana, and by the Delaware, Lackawanna & Western Railroad (now New Jersey Transit, converted to 25 kV AC) in the United States, and the Kolkata suburban railway (Bardhaman Main Line) in India, before it was converted to 25 kV 50 Hz AC.

Question: What voltage is being used in railway system of South Africa and Chile?
Answer: 3 kV DC

Question: Besides using 3kV DC what other power type is used in the former Soviet Union countries?
Answer: 25 kV 50 Hz AC

Question: What was New Jersey Transit called before?
Answer: Western Railroad

Question: What does the railway system of US use DC or AC?
Answer: AC
Title: Railway_electrification_system

Most electrification systems use overhead wires, but third rail is an option up to about 1,200 V. Third rail systems exclusively use DC distribution. The use of AC is not feasible because the dimensions of a third rail are physically very large compared with the skin depth that the alternating current penetrates to (0.3 millimetres or 0.012 inches) in a steel rail). This effect makes the resistance per unit length unacceptably high compared with the use of DC. Third rail is more compact than overhead wires and can be used in smaller-diameter tunnels, an important factor for subway systems.

Question: What type is mostly used third rail or overhead wires?
Answer: overhead wires

Question: Is trird rail system being used exclusively with AC or DC ?
Answer: DC distribution

Question: What depth does the alternating current penetrate in a steel rail?
Answer: skin depth

Question: What is more prefferable for subway lines?
Answer: Third rail

Question: What is physically more compact tird rail or overhead wires?
Answer: Third rail
Title: Railway_electrification_system

DC systems (especially third-rail systems) are limited to relatively low voltages and this can limit the size and speed of trains and cannot use low-level platform and also limit the amount of air-conditioning that the trains can provide. This may be a factor favouring overhead wires and high-voltage AC, even for urban usage. In practice, the top speed of trains on third-rail systems is limited to 100 mph (160 km/h) because above that speed reliable contact between the shoe and the rail cannot be maintained.

Question: Why DC system can effect the speed of trains?
Answer: low voltages

Question: Can DC systems use low-level platform?
Answer: cannot

Question: Besides speed and size what else the low voltage of DC system can effect?
Answer: air-conditioning

Question: What is the speed limit for third rail system trains?
Answer: 160 km/h

Question: What can become unreliable if the speed exceeds the limit of 100 mph for DC system trains?
Answer: contact between the shoe and the rail