Neptune is not visible to the unaided eye and is the only planet in the Solar System found by mathematical prediction rather than by empirical observation. Unexpected changes in the orbit of Uranus led Alexis Bouvard to deduce that its orbit was subject to gravitational perturbation by an unknown planet. Neptune was subsequently observed with a telescope on 23 September 1846 by Johann Galle within a degree of the position predicted by Urbain Le Verrier. Its largest moon, Triton, was discovered shortly thereafter, though none of the planet's remaining known 14 moons were located telescopically until the 20th century. The planet's distance from Earth gives it a very small apparent size, making it challenging to study with Earth-based telescopes. Neptune was visited by Voyager 2, when it flew by the planet on 25 August 1989. The advent of Hubble Space Telescope and large ground-based telescopes with adaptive optics has recently allowed for additional detailed observations from afar.


Which planet is compositionally similar to Neptune?

Neptune is similar in composition to Uranus, and both have compositions that differ from those of the larger gas giants, Jupiter and Saturn. Like Jupiter and Saturn, Neptune's atmosphere is composed primarily of hydrogen and helium, along with traces of hydrocarbons and possibly nitrogen, but contains a higher proportion of "ices" such as water, ammonia, and methane. However, its interior, like that of Uranus, is primarily composed of ices and rock, and hence Uranus and Neptune are normally considered "ice giants" to emphasise this distinction. Traces of methane in the outermost regions in part account for the planet's blue appearance.


What is Neptune's atmosphere primarily composed of?


What is the interior of Neptune composed of?


What weather did Voyager 2 observe on Neptune?

In contrast to the hazy, relatively featureless atmosphere of Uranus, Neptune's atmosphere has active and visible weather patterns. For example, at the time of the Voyager 2 flyby in 1989, the planet's southern hemisphere had a Great Dark Spot comparable to the Great Red Spot on Jupiter. These weather patterns are driven by the strongest sustained winds of any planet in the Solar System, with recorded wind speeds as high as 2,100 kilometres per hour (580 m/s; 1,300 mph). Because of its great distance from the Sun, Neptune's outer atmosphere is one of the coldest places in the Solar System, with temperatures at its cloud tops approaching 55 K (−218 °C). Temperatures at the planet's centre are approximately 5,400 K (5,100 °C). Neptune has a faint and fragmented ring system (labelled "arcs"), which was first detected during the 1960s and confirmed by Voyager 2.


What weather feature does Neptune have stronger than any other planet?


What were the wind speeds recorded on Neptune?


What is the cloud tops on Neptune temperature?


What is Neptune's planet center temperature?


Who drew Neptune after observing it with a telescope?

Some of the earliest recorded observations ever made through a telescope, Galileo's drawings on 28 December 1612 and 27 January 1613, contain plotted points that match up with what is now known to be the position of Neptune. On both occasions, Galileo seems to have mistaken Neptune for a fixed star when it appeared close—in conjunction—to Jupiter in the night sky; hence, he is not credited with Neptune's discovery. At his first observation in December 1612, Neptune was almost stationary in the sky because it had just turned retrograde that day. This apparent backward motion is created when Earth's orbit takes it past an outer planet. Because Neptune was only beginning its yearly retrograde cycle, the motion of the planet was far too slight to be detected with Galileo's small telescope. In July 2009, University of Melbourne physicist David Jamieson announced new evidence suggesting that Galileo was at least aware that the 'star' he had observed had moved relative to the fixed stars.


What happens when Neptune goes retrograde?


Who recently researched the original observation of Neptune?


What year did Alexis Bouvard publish relevant astronomical tables?

In 1821, Alexis Bouvard published astronomical tables of the orbit of Neptune's neighbour Uranus. Subsequent observations revealed substantial deviations from the tables, leading Bouvard to hypothesise that an unknown body was perturbing the orbit through gravitational interaction. In 1843, John Couch Adams began work on the orbit of Uranus using the data he had. Via Cambridge Observatory director James Challis, he requested extra data from Sir George Airy, the Astronomer Royal, who supplied it in February 1844. Adams continued to work in 1845–46 and produced several different estimates of a new planet.


When did John Couch Adams begin working on the orbit of Uranus?


What did the extra data John Couch Adams received produce?


Meanwhile, Le Verrier by letter urged Berlin Observatory astronomer Johann Gottfried Galle to search with the observatory's refractor. Heinrich d'Arrest, a student at the observatory, suggested to Galle that they could compare a recently drawn chart of the sky in the region of Le Verrier's predicted location with the current sky to seek the displacement characteristic of a planet, as opposed to a fixed star. On the evening of 23 September 1846, the day Galle received the letter, he discovered Neptune within 1° of where Le Verrier had predicted it to be, about 12° from Adams' prediction. Challis later realised that he had observed the planet twice, on 4 and 12 August, but did not recognise it as a planet because he lacked an up-to-date star map and was distracted by his concurrent work on comet observations.


How many degrees off was Adams' prediction?


What was Challis looking for when he saw Neptune the first two times?


What two countries argued over credit for the discovery of Neptune?

In the wake of the discovery, there was much nationalistic rivalry between the French and the British over who deserved credit for the discovery. Eventually, an international consensus emerged that both Le Verrier and Adams jointly deserved credit. Since 1966, Dennis Rawlins has questioned the credibility of Adams's claim to co-discovery, and the issue was re-evaluated by historians with the return in 1998 of the "Neptune papers" (historical documents) to the Royal Observatory, Greenwich. After reviewing the documents, they suggest that "Adams does not deserve equal credit with Le Verrier for the discovery of Neptune. That credit belongs only to the person who succeeded both in predicting the planet's place and in convincing astronomers to search for it."


Who ultimately deserved credit for the discovery of Neptune?


Who questioned Adams's claim to co-discovery of Neptune?


Who predicted Neptune's place and convinced astronomer's to search for it?


Who did not deserve credit to co-discovery of Neptune?


Claiming the right to name his discovery, Le Verrier quickly proposed the name Neptune for this new planet, though falsely stating that this had been officially approved by the French Bureau des Longitudes. In October, he sought to name the planet Le Verrier, after himself, and he had loyal support in this from the observatory director, François Arago. This suggestion met with stiff resistance outside France. French almanacs quickly reintroduced the name Herschel for Uranus, after that planet's discoverer Sir William Herschel, and Leverrier for the new planet.


What country approved Neptune's first name?


What did the discoverer want to name Neptune first?


What first introduced Neptune and Uranus's names?


Who did not approve of the first name for Neptune?


What is the Chinese, Japanese, and Korean translations for Neptune?

Most languages today, even in countries that have no direct link to Greco-Roman culture, use some variant of the name "Neptune" for the planet. However, in Chinese, Japanese, and Korean, the planet's name was translated as "sea king star" (海王星), because Neptune was the god of the sea. In Mongolian, Neptune is called Dalain Van (Далайн ван), reflecting its namesake god's role as the ruler of the sea. In modern Greek the planet is called Poseidon (Ποσειδώνας, Poseidonas), the Greek counterpart of Neptune. In Hebrew, "Rahab" (רהב), from a Biblical sea monster mentioned in the Book of Psalms, was selected in a vote managed by the Academy of the Hebrew Language in 2009 as the official name for the planet, even though the existing Latin term "Neptun" (נפטון) is commonly used. In Māori, the planet is called Tangaroa, named after the Māori god of the sea. In Nahuatl, the planet is called Tlāloccītlalli, named after the rain god Tlāloc.


What was the Biblical sea monster that Neptune is named in Hebrew?


What was Neptune before Pluto was discovered?

From its discovery in 1846 until the subsequent discovery of Pluto in 1930, Neptune was the farthest known planet. When Pluto was discovered it was considered a planet, and Neptune thus became the penultimate known planet, except for a 20-year period between 1979 and 1999 when Pluto's elliptical orbit brought it closer to the Sun than Neptune. The discovery of the Kuiper belt in 1992 led many astronomers to debate whether Pluto should be considered a planet or as part of the Kuiper belt. In 2006, the International Astronomical Union defined the word "planet" for the first time, reclassifying Pluto as a "dwarf planet" and making Neptune once again the outermost known planet in the Solar System.


What discovery made astronomer's debate Pluto's status as a planet?


What year did the International Astronomical Union define the word planet?


Now that Pluto isn't a planet, what is Neptune known for in our solar system?


What period was Pluto closer to the sun than Neptune?


Neptune's mass of 1.0243×1026 kg, is intermediate between Earth and the larger gas giants: it is 17 times that of Earth but just 1/19th that of Jupiter.[d] Its gravity at 1 bar is 11.15 m/s2, 1.14 times the surface gravity of Earth, and surpassed only by Jupiter. Neptune's equatorial radius of 24,764 km is nearly four times that of Earth. Neptune, like Uranus, is an ice giant, a subclass of giant planet, due to their smaller size and higher concentrations of volatiles relative to Jupiter and Saturn. In the search for extrasolar planets, Neptune has been used as a metonym: discovered bodies of similar mass are often referred to as "Neptunes", just as scientists refer to various extrasolar bodies as "Jupiters".


How much more mass does Neptune have compared to Earth?


What is Neptune referred to due to it's size and concentration of volatiles?


The mantle is equivalent to 10 to 15 Earth masses and is rich in water, ammonia and methane. As is customary in planetary science, this mixture is referred to as icy even though it is a hot, dense fluid. This fluid, which has a high electrical conductivity, is sometimes called a water–ammonia ocean. The mantle may consist of a layer of ionic water in which the water molecules break down into a soup of hydrogen and oxygen ions, and deeper down superionic water in which the oxygen crystallises but the hydrogen ions float around freely within the oxygen lattice. At a depth of 7000 km, the conditions may be such that methane decomposes into diamond crystals that rain downwards like hailstones. Very-high-pressure experiments at the Lawrence Livermore National Laboratory suggest that the base of the mantle may comprise an ocean of liquid carbon with floating solid 'diamonds'.


What is the hot, dense fluid in Neptune referred to as?


What does the fluid in Neptune have a high conductivity of?


How deep does Neptune's water-ammonia ocean go?


At high altitudes, Neptune's atmosphere is 80% hydrogen and 19% helium. A trace amount of methane is also present. Prominent absorption bands of methane exist at wavelengths above 600 nm, in the red and infrared portion of the spectrum. As with Uranus, this absorption of red light by the atmospheric methane is part of what gives Neptune its blue hue, although Neptune's vivid azure differs from Uranus's milder cyan. Because Neptune's atmospheric methane content is similar to that of Uranus, some unknown atmospheric constituent is thought to contribute to Neptune's colour.


Where are absorption bands of methane on Neptune?


What planet also gets it's color from atmospheric constituent?


What color is Uranus, compared to Neptune?


What is Neptune's clouds competition variants dependent on?

Models suggest that Neptune's troposphere is banded by clouds of varying compositions depending on altitude. The upper-level clouds lie at pressures below one bar, where the temperature is suitable for methane to condense. For pressures between one and five bars (100 and 500 kPa), clouds of ammonia and hydrogen sulfide are thought to form. Above a pressure of five bars, the clouds may consist of ammonia, ammonium sulfide, hydrogen sulfide and water. Deeper clouds of water ice should be found at pressures of about 50 bars (5.0 MPa), where the temperature reaches 273 K (0 °C). Underneath, clouds of ammonia and hydrogen sulfide may be found.


Which clouds on Neptune are suitable for methane to condense?


What clouds form between one and five bars on Neptune?


On Neptune, what do clouds above five bars consist of?


What is the temperature on Neptune's clouds that are at 50 bars?


On Neptune, which clouds cast shadows on the cloud deck below it?

High-altitude clouds on Neptune have been observed casting shadows on the opaque cloud deck below. There are also high-altitude cloud bands that wrap around the planet at constant latitude. These circumferential bands have widths of 50–150 km and lie about 50–110 km above the cloud deck. These altitudes are in the layer where weather occurs, the troposphere. Weather does not occur in the higher stratosphere or thermosphere. Unlike Uranus, Neptune's composition has a higher volume of ocean, whereas Uranus has a smaller mantle.


What are the widths of the cloud bands on Neptune?


Where are the high altitude bands of clouds on Neptune?


What does Neptune have more of compared to Uranus?


Where on Neptune does weather not occur?


What is Neptune's temperature in the thermosphere?

For reasons that remain obscure, the planet's thermosphere is at an anomalously high temperature of about 750 K. The planet is too far from the Sun for this heat to be generated by ultraviolet radiation. One candidate for a heating mechanism is atmospheric interaction with ions in the planet's magnetic field. Other candidates are gravity waves from the interior that dissipate in the atmosphere. The thermosphere contains traces of carbon dioxide and water, which may have been deposited from external sources such as meteorites and dust.


What would interact with Neptune's magnetic field to make it warm?


Where would gravity waves in Neptune's interior dissipate?


What does Neptune's thermosphere containers traces of?


What is the rotational axis of Neptune's magnetic field?

Neptune also resembles Uranus in its magnetosphere, with a magnetic field strongly tilted relative to its rotational axis at 47° and offset at least 0.55 radii, or about 13500 km from the planet's physical centre. Before Voyager 2's arrival at Neptune, it was hypothesised that Uranus's tilted magnetosphere was the result of its sideways rotation. In comparing the magnetic fields of the two planets, scientists now think the extreme orientation may be characteristic of flows in the planets' interiors. This field may be generated by convective fluid motions in a thin spherical shell of electrically conducting liquids (probably a combination of ammonia, methane and water) resulting in a dynamo action.


Where is Neptune's magnetic field offset from the physical centre?


What planet besides Neptune has a sideways rotation?


What might cause Neptune's extreme orientation?


What is Neptune's dipole magnetic moment?

The dipole component of the magnetic field at the magnetic equator of Neptune is about 14 microteslas (0.14 G). The dipole magnetic moment of Neptune is about 2.2 × 1017 T·m3 (14 μT·RN3, where RN is the radius of Neptune). Neptune's magnetic field has a complex geometry that includes relatively large contributions from non-dipolar components, including a strong quadrupole moment that may exceed the dipole moment in strength. By contrast, Earth, Jupiter and Saturn have only relatively small quadrupole moments, and their fields are less tilted from the polar axis. The large quadrupole moment of Neptune may be the result of offset from the planet's centre and geometrical constraints of the field's dynamo generator.


What is one of Neptune's non-dipolar component what may exceed the dipole moment in strength?


Which three planets have small quadrupole moments compared to Neptune?


Besides the geometrical constraints of Neptune's dynamo generator, what is another result of the quadrupole moment?


What is the dipole component of the magnetic field at the magnetic equator of neptune?


What system, like Saturn, does Neptune have?

Neptune has a planetary ring system, though one much less substantial than that of Saturn. The rings may consist of ice particles coated with silicates or carbon-based material, which most likely gives them a reddish hue. The three main rings are the narrow Adams Ring, 63,000 km from the centre of Neptune, the Le Verrier Ring, at 53,000 km, and the broader, fainter Galle Ring, at 42,000 km. A faint outward extension to the Le Verrier Ring has been named Lassell; it is bounded at its outer edge by the Arago Ring at 57,000 km.


What might the ice particles of Neptune's rings be coated with?


Where is Adams ring from the center of Neptune?


Where is the La Verrier ring from the center of Neptune?


Neptune's weather is characterised by extremely dynamic storm systems, with winds reaching speeds of almost 600 m/s (2,200 km/h; 1,300 mph)—nearly reaching supersonic flow. More typically, by tracking the motion of persistent clouds, wind speeds have been shown to vary from 20 m/s in the easterly direction to 325 m/s westward. At the cloud tops, the prevailing winds range in speed from 400 m/s along the equator to 250 m/s at the poles. Most of the winds on Neptune move in a direction opposite the planet's rotation. The general pattern of winds showed prograde rotation at high latitudes vs. retrograde rotation at lower latitudes. The difference in flow direction is thought to be a "skin effect" and not due to any deeper atmospheric processes. At 70° S latitude, a high-speed jet travels at a speed of 300 m/s.


What is the high wind speed on Neptune's cloud tops?


Which direction does Neptune's winds move relevant to the plant's rotation?


What is the effect called that describes the flow direction on Neptune?


How much warmer is Neptune's south pole to the rest of it's atmosphere?

In 2007, it was discovered that the upper troposphere of Neptune's south pole was about 10 K warmer than the rest of its atmosphere, which averages approximately 73 K (−200 °C). The temperature differential is enough to let methane, which elsewhere is frozen in the troposphere, escape into the stratosphere near the pole. The relative "hot spot" is due to Neptune's axial tilt, which has exposed the south pole to the Sun for the last quarter of Neptune's year, or roughly 40 Earth years. As Neptune slowly moves towards the opposite side of the Sun, the south pole will be darkened and the north pole illuminated, causing the methane release to shift to the north pole.


Where does methane in the south pole escape to on Neptune?


What is the average temperature of Neptune's south pole?


How many earth years is Neptune's south pole exposed to the sun?


To which pole will Neptune's methane shift to as it moves to the opposite side of the sun?


What white cloud group on Neptune is farther south than the dark great spot?

The Scooter is another storm, a white cloud group farther south than the Great Dark Spot. This nickname first arose during the months leading up to the Voyager 2 encounter in 1989, when they were observed moving at speeds faster than the Great Dark Spot (and images acquired later would subsequently reveal the presence of clouds moving even faster than those that had initially been detected by Voyager 2). The Small Dark Spot is a southern cyclonic storm, the second-most-intense storm observed during the 1989 encounter. It was initially completely dark, but as Voyager 2 approached the planet, a bright core developed and can be seen in most of the highest-resolution images.


When was The Scooter on Neptune observed?


What type of storm is The Scooter on Neptune?


What is the second most intense storm on Neptune?


Where are Neptune's dark spots thought to occur?

Neptune's dark spots are thought to occur in the troposphere at lower altitudes than the brighter cloud features, so they appear as holes in the upper cloud decks. As they are stable features that can persist for several months, they are thought to be vortex structures. Often associated with dark spots are brighter, persistent methane clouds that form around the tropopause layer. The persistence of companion clouds shows that some former dark spots may continue to exist as cyclones even though they are no longer visible as a dark feature. Dark spots may dissipate when they migrate too close to the equator or possibly through some other unknown mechanism.


What do Neptune's dark spots appear as in the cloud decks?


Since Neptune's dark spots persist for several months, what are they thought to be?


What on Neptune are associated with dark spots that are brighter?


When Neptune's dark spots migrate too close to the equator, what do they do?


Why might Neptune have more varied weather than Uranus?

Neptune's more varied weather when compared to Uranus is due in part to its higher internal heating. Although Neptune lies over 50% further from the Sun than Uranus, and receives only 40% its amount of sunlight, the two planets' surface temperatures are roughly equal. The upper regions of Neptune's troposphere reach a low temperature of 51.8 K (−221.3 °C). At a depth where the atmospheric pressure equals 1 bar (100 kPa), the temperature is 72.00 K (−201.15 °C). Deeper inside the layers of gas, the temperature rises steadily. As with Uranus, the source of this heating is unknown, but the discrepancy is larger: Uranus only radiates 1.1 times as much energy as it receives from the Sun; whereas Neptune radiates about 2.61 times as much energy as it receives from the Sun. Neptune is the farthest planet from the Sun, yet its internal energy is sufficient to drive the fastest planetary winds seen in the Solar System. Depending on the thermal properties of its interior, the heat left over from Neptune's formation may be sufficient to explain its current heat flow, though it is more difficult to simultaneously explain Uranus's lack of internal heat while preserving the apparent similarity between the two planets.


How much farther is Neptune from the Sun than Uranus?


How much percentage of the sun does Neptune get compared to Uranus?


How much more energy does Neptune radiate than it receives?


The current heat flow on Neptune might be explained by what?


When did Neptune complete it's first barycentric orbit since it's discovery?

On 11 July 2011, Neptune completed its first full barycentric orbit since its discovery in 1846, although it did not appear at its exact discovery position in the sky, because Earth was in a different location in its 365.26-day orbit. Because of the motion of the Sun in relation to the barycentre of the Solar System, on 11 July Neptune was also not at its exact discovery position in relation to the Sun; if the more common heliocentric coordinate system is used, the discovery longitude was reached on 12 July 2011.


Why didn't Neptune appear to be in it's exact discover position?


Using the heliocentric coordinate system, when did Neptune reach the discovery longitude?


What is the region behind Neptune called?

Neptune's orbit has a profound impact on the region directly beyond it, known as the Kuiper belt. The Kuiper belt is a ring of small icy worlds, similar to the asteroid belt but far larger, extending from Neptune's orbit at 30 AU out to about 55 AU from the Sun. Much in the same way that Jupiter's gravity dominates the asteroid belt, shaping its structure, so Neptune's gravity dominates the Kuiper belt. Over the age of the Solar System, certain regions of the Kuiper belt became destabilised by Neptune's gravity, creating gaps in the Kuiper belt's structure. The region between 40 and 42 AU is an example.


Where is the Kuiper belt relative to Neptune?


What did Neptune's gravity do to Kuiper belt?


What is the fraction of the most heavily populated resonance in the Kuiper belt?

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.


What is the best known, and largest, object in the Kuiper belt?


How many known objects is in the most populated resonance of the Kuiper belt?


What is the resonance of Pluto in the Kuiper belt?


Which resonances are less populated in the Kuiper belt?


What is the resonance of Neptune trojans?

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.


What is the only object identified with Neptune's trailing L5 Lagrangian point?


What is Neptune's temporary quasi-satellite named?


How long has Neptune's quasi-satellite been with Neptune?


What could have blasted Neptune and Uranus's atmosphere with radiation, aiding in creation?

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.


What is too low to account for the formation of Neptune?


If Neptune was formed from instabilities within the original protoplanetary disc, what was it not formed by?


If Neptune formed closer to the sun, what is the matter density?

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.


If Neptune formed closer to the sun, what caused it to migrate to it's current orbit?


What is the most widely accepted explanation of Neptune's formation called?


What does The Nice model consider effected the migration of 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).


What orbit does Triton have around Neptune?


What does Triton's orbit suggest about it's relation to Neptune?


What discovered six moons of Neptune in 1989?

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.


What is the second most massive Neptunian moon?


Which are Neptune's four innermost moons?


When was Neptune's moon Larissa discovered?


What is Neptune's angular diameter range?

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.


The advent of what telescope made it easier to study Neptune?


When was the first useful observation of Neptune from the ground?


What seasons are Neptune currently entering?


What was discovered around Neptune in 2004 and 2005?


What is the only spacecraft to visit 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.


When did a spacecraft get closest to Neptune?


What near Neptune did a spacecraft visit dangerously close?


What program aired on PBS about Neptune?


When is the next hypothetical mission to 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.


What about Neptune did NASA propose in 2003 in their "Vision Missions Studies"?


When can we expect Argo to visit Triton?


What is of the factors the capital cost of electrification system depends on?

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.


How do some locomotives function in order to be more flexible in operation?


What are two types of revenue obtained through railway transportation?


What is the main disadvantage of railway electrification?


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.


How is electricity being generated for electric locomotives?


What entity provides distribution lines, switches and transformers?


What is the principal alternative to electric railways?

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.


What locomotives are usually more reliable?


What do some electric traction systems provide?


What type of fuel do diesel locomotives use?


What is one of the sources electricity is being generated from?


What is a safety hazard to track workers?

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.


What issue can complicate electric railway service?


What is a safer alternative to third rails?


Why overhead wires are not being widely used?


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.


Why is DC motor being used more than AC type?


What are two types of railway transportation still use DC motor?


Why do motors have little space for insulation?

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.)


Why 1kV voltage is almost always used by rail systems?


What is most common volatage range used by railway system?


Is "low" voltage used by trains safe for people?


What type of electric power garantees lesser loss?

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.


Which type of supply for electric motors creates electromagnetic radiation?


Which type of power does require three-phase transmission?


What can electromagnetic radiation interfere with?


Where was an experimental 6kV DC railway built?


What is most common voltage for DC supply?

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.


How many narrow-gauge lines in Slovakia?


What railway line is DC being used in Portugal?


Where in India line has been converted to AC?


What voltage is being used in railway system of South Africa and Chile?

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.


Besides using 3kV DC what other power type is used in the former Soviet Union countries?


What was New Jersey Transit called before?


What does the railway system of US use DC or AC?


What type is mostly used third rail or overhead wires?

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.


Is trird rail system being used exclusively with AC or DC ?


What depth does the alternating current penetrate in a steel rail?


What is more prefferable for subway lines?


What is physically more compact tird rail or overhead wires?


Why DC system can effect the speed of trains?

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.


Besides speed and size what else the low voltage of DC system can effect?


What is the speed limit for third rail system trains?


What can become unreliable if the speed exceeds the limit of 100 mph for DC system trains?


What is the other name for the street trams?

Some street trams (streetcars) used conduit third-rail current collection. The third rail was below street level. The tram picked up the current through a plough (U.S. "plow") accessed through a narrow slot in the road. In the United States, much (though not all) of the former streetcar system in Washington, D.C. (discontinued in 1962) was operated in this manner to avoid the unsightly wires and poles associated with electric traction. The same was true with Manhattan's former streetcar system. The evidence of this mode of running can still be seen on the track down the slope on the northern access to the abandoned Kingsway Tramway Subway in central London, United Kingdom, where the slot between the running rails is clearly visible, and on P and Q Streets west of Wisconsin Avenue in the Georgetown neighborhood of Washington DC, where the abandoned tracks have not been paved over. The slot can easily be confused with the similar looking slot for cable trams/cars (in some cases, the conduit slot was originally a cable slot). The disadvantage of conduit collection included much higher initial installation costs, higher maintenance costs, and problems with leaves and snow getting in the slot. For this reason, in Washington, D.C. cars on some lines converted to overhead wire on leaving the city center, a worker in a "plough pit" disconnecting the plough while another raised the trolley pole (hitherto hooked down to the roof) to the overhead wire. In New York City for the same reasons of cost and operating efficiency outside of Manhattan overhead wire was used. A similar system of changeover from conduit to overhead wire was also used on the London tramways, notably on the southern side; a typical changeover point was at Norwood, where the conduit snaked sideways from between the running rails, to provide a park for detached shoes or ploughs.


Where is third rail situated in the street trams system?


What area in US discontinued using overhead wires for streetcars in 1962?


What external and weather factors can effect conduit slot?


What are the main reasons the conduit lines were converted to overhead wire system?


What year the "second generation" of tram system began to operate in France?

A new approach to avoiding overhead wires is taken by the "second generation" tram/streetcar system in Bordeaux, France (entry into service of the first line in December 2003; original system discontinued in 1958) with its APS (alimentation par sol – ground current feed). This involves a third rail which is flush with the surface like the tops of the running rails. The circuit is divided into segments with each segment energized in turn by sensors from the car as it passes over it, the remainder of the third rail remaining "dead". Since each energized segment is completely covered by the lengthy articulated cars, and goes dead before being "uncovered" by the passage of the vehicle, there is no danger to pedestrians. This system has also been adopted in some sections of the new tram systems in Reims, France (opened 2011) and Angers, France (also opened 2011). Proposals are in place for a number of other new services including Dubai, UAE; Barcelona, Spain; Florence, Italy; Marseille, France; Gold Coast, Australia; Washington, D.C., U.S.A.; Brasília, Brazil and Tours, France.


When was the original system discontinued?


How is the circuit of the third rail divided?


Does energized segment of third rail pose the threat to pedestrians if uncovered?


What type of system does London Underground use?

The London Underground in England is one of the few networks that uses a four-rail system. The additional rail carries the electrical return that, on third rail and overhead networks, is provided by the running rails. On the London Underground, a top-contact third rail is beside the track, energized at +420v DC, and a top-contact fourth rail is located centrally between the running rails at −210v DC, which combine to provide a traction voltage of 630v DC. London Underground is now upgrading its fourth rail system to 750v DC with a positive conductor rail energised to +500v DC and a negative conductor rail energised to -250v DC. However, many older sections in tunnels are still energised to 630v DC. The same system was used for Milan's earliest underground line, Milan Metro's line 1, whose more recent lines use an overhead catenary or a third rail.


What is the volatage surge of the third rail of London Underground system?


Where was the system similar to London Underground used as well?


The key advantage of the four-rail system is that neither running rail carries any current. This scheme was introduced because of the problems of return currents, intended to be carried by the earthed (grounded) running rail, flowing through the iron tunnel linings instead. This can cause electrolytic damage and even arcing if the tunnel segments are not electrically bonded together. The problem was exacerbated because the return current also had a tendency to flow through nearby iron pipes forming the water and gas mains. Some of these, particularly Victorian mains that predated London's underground railways, were not constructed to carry currents and had no adequate electrical bonding between pipe segments. The four-rail system solves the problem. Although the supply has an artificially created earth point, this connection is derived by using resistors which ensures that stray earth currents are kept to manageable levels. Power-only rails can be mounted on strongly insulating ceramic chairs to minimise current leak, but this is not possible for running rails which have to be seated on stronger metal chairs to carry the weight of trains. However, elastomeric rubber pads placed between the rails and chairs can now solve part of the problem by insulating the running rails from the current return should there be a leakage through the running rails.


How are stray earth currents kept to a manageable levels?


What insures minimal current leak during power rails instalation?


How did return current effect water and gas in iron pipes?


What is the crucial advantage of four-rail system?


Why some sections of Bakerloo and District lines were rewired to three-rail system?

On tracks that London Underground share with National Rail third-rail stock (the Bakerloo and District lines both have such sections), the centre rail is connected to the running rails, allowing both types of train to operate, at a compromise voltage of 660 V. Underground trains pass from one section to the other at speed; lineside electrical connections and resistances separate the two types of supply. These routes were originally solely electrified on the four-rail system by the LNWR before National Rail trains were rewired to their standard three-rail system to simplify rolling stock use.


What is the voltage shared two types of trains UK railroad system?


How did it become possible to share the voltage for different types of train?


Why some lines of Paris Metro have to operate on a four-rail system?

A few lines of the Paris Métro in France operate on a four-rail power scheme because they run on rubber tyres which run on a pair of narrow roadways made of steel and, in some places, concrete. Since the tyres do not conduct the return current, the two guide rails provided outside the running 'roadways' double up as conductor rails, so at least electrically it is a four-rail scheme. One of the guide rails is bonded to the return conventional running rails situated inside the roadway so a single polarity supply is required. The trains are designed to operate from either polarity of supply, because some lines use reversing loops at one end, causing the train to be reversed during every complete journey. The loop was originally provided to save the original steam locomotives having to 'run around' the rest of the train saving much time. Today, the driver does not have to change ends at termini provided with such a loop, but the time saving is not so significant as it takes almost as long to drive round the loop as it does to change ends. Many of the original loops have been lost as lines were extended.


What was the solution for the return current problem in Paris Metro?


What is required in order for the guide rails to operate properly?


How train is able to turn around after each completed journey?


How can different range of voltages be supplied for AC locomotives?

An early advantage of AC is that the power-wasting resistors used in DC locomotives for speed control were not needed in an AC locomotive: multiple taps on the transformer can supply a range of voltages. Separate low-voltage transformer windings supply lighting and the motors driving auxiliary machinery. More recently, the development of very high power semiconductors has caused the classic "universal" AC/DC motor to be largely replaced with the three-phase induction motor fed by a variable frequency drive, a special inverter that varies both frequency and voltage to control motor speed. These drives can run equally well on DC or AC of any frequency, and many modern electric locomotives are designed to handle different supply voltages and frequencies to simplify cross-border operation.


What is the main advantage of an induction motor?


DC commutating electric motors, if fitted with laminated pole pieces, become universal motors because they can also operate on AC; reversing the current in both stator and rotor does not reverse the motor. But the now-standard AC distribution frequencies of 50 and 60 Hz caused difficulties with inductive reactance and eddy current losses. Many railways chose low AC frequencies to overcome these problems. They must be converted from utility power by motor-generators or static inverters at the feeding substations or generated at dedicated traction powerstations.


What problems did AC distribution cause?


How do railways try to solve the problem of inductive reactance of AC system?


How did non-standard gauge trains start to operate with high-voltage AC?

High-voltage AC overhead systems are not only for standard gauge national networks. The meter gauge Rhaetian Railway (RhB) and the neighbouring Matterhorn Gotthard Bahn (MGB) operate on 11 kV at 16.7 Hz frequency. Practice has proven that both Swiss and German 15 kV trains can operate under these lower voltages. The RhB started trials of the 11 kV system in 1913 on the Engadin line (St. Moritz-Scuol/Tarasp). The MGB constituents Furka-Oberalp-Bahn (FO) and Brig-Visp-Zermatt Bahn (BVZ) introduced their electric services in 1941 and 1929 respectively, adopting the already proven RhB system.


When was the first trail of RhB system tested?


What frequency was typically used on US Amtrak?

In the United States, 25 Hz, a once-common industrial power frequency is used on Amtrak's 25 Hz traction power system at 12 kV on the Northeast Corridor between Washington, D.C. and New York City and on the Keystone Corridor between Harrisburg, Pennsylvania and Philadelphia. SEPTA's 25 Hz traction power system uses the same 12 kV voltage on the catenary in Northeast Philadelphia. This allows for the trains to operate on both the Amtrak and SEPTA power systems. Apart from having an identical catenary voltage, the power distribution systems of Amtrak and SEPTA are very different. The Amtrak power distribution system has a 138 kV transmission network that provides power to substations which then transform the voltage to 12 kV to feed the catenary system. The SEPTA power distribution system uses a 2:1 ratio autotransformer system, with the catenary fed at 12 kV and a return feeder wire fed at 24 kV. The New York, New Haven and Hartford Railroad used an 11 kV system between New York City and New Haven, Connecticut which was converted to 12.5 kV 60 Hz in 1987.


What specification is similar for both Amtrak and Septa systems?


When was a 11kV system of NY, New Haven and Hartford was converted to 12.5 kV?


When was overhead wires system being used for the first time in UK?

In the UK, the London, Brighton and South Coast Railway pioneered overhead electrification of its suburban lines in London, London Bridge to Victoria being opened to traffic on 1 December 1909. Victoria to Crystal Palace via Balham and West Norwood opened in May 1911. Peckham Rye to West Norwood opened in June 1912. Further extensions were not made owing to the First World War. Two lines opened in 1925 under the Southern Railway serving Coulsdon North and Sutton railway station. The lines were electrified at 6.7 kV 25 Hz. It was announced in 1926 that all lines were to be converted to DC third rail and the last overhead electric service ran in September 1929.


What line used the overhead wire system first Victoria to Crystal Palace or Peckham Rye to West Noorwood?


What was the cause of lines not being extended?


What voltage was used in the two lines opened in 1925 of Southern Railway?


What countries used three-phase AC system in the the beginning of 20th century?

Three-phase AC railway electrification was used in Italy, Switzerland and the United States in the early twentieth century. Italy was the major user, for lines in the mountainous regions of northern Italy from 1901 until 1976. The first lines were the Burgdorf-Thun line in Switzerland (1899), and the lines of the Ferrovia Alta Valtellina from Colico to Chiavenna and Tirano in Italy, which were electrified in 1901 and 1902. Other lines where the three-phase system were used were the Simplon Tunnel in Switzerland from 1906 to 1930, and the Cascade Tunnel of the Great Northern Railway in the United States from 1909 to 1927.


What country was a bigger user compare to the three of them?


Where did Italy start using the AC system?


How long did the AC system last in northern Italy?


How long did three-phase system operate in Cascade Tunnel?


What country has first tried to use single-phase AC?

The first attempts to use standard-frequency single-phase AC were made in Hungary as far back as 1923, by the Hungarian Kálmán Kandó on the line between Budapest-Nyugati and Alag, using 16 kV at 50 Hz. The locomotives carried a four-pole rotating phase converter feeding a single traction motor of the polyphase induction type at 600 to 1,100 V. The number of poles on the 2,500 hp motor could be changed using slip rings to run at one of four synchronous speeds. The tests were a success so, from 1932 until the 1960s, trains on the Budapest-Hegyeshalom line (towards Vienna) regularly used the same system. A few decades after the Second World War, the 16 kV was changed to the Russian and later French 25 kV system.


What frequency did the line of Hungarian rail system used in 1923?


What type of the converter was used in hungarian locomotives of that time?


How could the locomotives run on four speed levels?


What system was adopted in Hungary after WWII?


What was the main requirement for electric feeder stations?

To prevent the risk of out-of-phase supplies mixing, sections of line fed from different feeder stations must be kept strictly isolated. This is achieved by Neutral Sections (also known as Phase Breaks), usually provided at feeder stations and midway between them although, typically, only half are in use at any time, the others being provided to allow a feeder station to be shut down and power provided from adjacent feeder stations. Neutral Sections usually consist of an earthed section of wire which is separated from the live wires on either side by insulating material, typically ceramic beads, designed so that the pantograph will smoothly run from one section to the other. The earthed section prevents an arc being drawn from one live section to the other, as the voltage difference may be higher than the normal system voltage if the live sections are on different phases and the protective circuit breakers may not be able to safely interrupt the considerable current that would flow. To prevent the risk of an arc being drawn across from one section of wire to earth, when passing through the neutral section, the train must be coasting and the circuit breakers must be open. In many cases, this is done manually by the drivers. To help them, a warning board is provided just before both the neutral section and an advance warning some distance before. A further board is then provided after the neutral section to tell drivers to re-close the circuit breaker, although drivers must not do this until the rear pantograph has passed this board. In the UK, a system known as Automatic Power Control (APC) automatically opens and closes the circuit breaker, this being achieved by using sets of permanent magnets alongside the track communicating with a detector on the train. The only action needed by the driver is to shut off power and coast and therefore warning boards are still provided at and on the approach to neutral sections.


What invention prevented lines from getting mixed?


What was the part of wire in Phase Break sections an arc being drawn from one wire to another?


How were the drivers warned to start coasting the train?


What should the driver do in order to open and close the circuit breaker?


What nowdays electrification systems can use?

Modern electrification systems take AC energy from a power grid which is delivered to a locomotive and converted to a DC voltage to be used by traction motors. These motors may either be DC motors which directly use the DC or they may be 3-phase AC motors which require further conversion of the DC to 3-phase AC (using power electronics). Thus both systems are faced with the same task: converting and transporting high-voltage AC from the power grid to low-voltage DC in the locomotive. Where should this conversion take place and at what voltage and current (AC or DC) should the power flow to the locomotive? And how does all this relate to energy-efficiency? Both the transmission and conversion of electric energy involve losses: ohmic losses in wires and power electronics, magnetic field losses in transformers and smoothing reactors (inductors). Power conversion for a DC system takes place mainly in a railway substation where large, heavy, and more efficient hardware can be used as compared to an AC system where conversion takes place aboard the locomotive where space is limited and losses are significantly higher. Also, the energy used to blow air to cool transformers, power electronics (including rectifiers), and other conversion hardware must be accounted for.


What is the main action AC and DC systems have to deal with?


What type of losses happen during conversion and transmission in wires and electronics?


What kind of losses take place in transformers and inductors during conversion/transmission process?


What two systems were compare in the Soviet Union in 1970?

In the Soviet Union, in the 1970s, a comparison was made between systems electrified at 3 kV DC and 25 kV AC (50 Hz). The results showed that percentage losses in the overhead wires (catenary and contact wires) was over 3 times greater for 3 kV DC than for 25 kV AC. But when the conversion losses were all taken into account and added to overhead wire losses (including cooling blower energy) the 25 kV AC lost a somewhat higher percent of energy than for 3 kV DC. Thus in spite of the much higher losses in the catenary, the 3 kV DC was a little more energy efficient than AC in providing energy from the USSR power grid to the terminals of the traction motors (all DC at that time). While both systems use energy in converting higher voltage AC from the USSR's power grid to lower voltage DC, the conversions for the DC system all took place (at higher efficiency) in the railway substation, while most of the conversion for the AC system took place inside the locomotive (at lower efficiency). Consider also that it takes energy to constantly move this mobile conversion hardware over the rails while the stationary hardware in the railway substation doesn't incur this energy cost. For more details see: Wiki: Soviet Union DC vs. AC.


Which system had higher losses in overhead wires?


Which system was used in Soviet Union after all calculations?


What came with lesser lesser cost mobile conversion hardware or stationary hardware?


What can be seen in the newly electrified lines?

Newly electrified lines often show a "sparks effect", whereby electrification in passenger rail systems leads to significant jumps in patronage / revenue. The reasons may include electric trains being seen as more modern and attractive to ride, faster and smoother service, and the fact that electrification often goes hand in hand with a general infrastructure and rolling stock overhaul / replacement, which leads to better service quality (in a way that theoretically could also be achieved by doing similar upgrades yet without electrification). Whatever the causes of the sparks effect, it is well established for numerous routes that have electrified over decades.


What can electrification of modern trains effect?


How can better service quality be achieved?


What is a major factor whn it comes to electrification?

Network effects are a large factor with electrification. When converting lines to electric, the connections with other lines must be considered. Some electrifications have subsequently been removed because of the through traffic to non-electrified lines. If through traffic is to have any benefit, time consuming engine switches must occur to make such connections or expensive dual mode engines must be used. This is mostly an issue for long distance trips, but many lines come to be dominated by through traffic from long-haul freight trains (usually running coal, ore, or containers to or from ports). In theory, these trains could enjoy dramatic savings through electrification, but it can be too costly to extend electrification to isolated areas, and unless an entire network is electrified, companies often find that they need to continue use of diesel trains even if sections are electrified. The increasing demand for container traffic which is more efficient when utilizing the double-stack car also has network effect issues with existing electrifications due to insufficient clearance of overhead electrical lines for these trains, but electrification can be built or modified to have sufficient clearance, at additional cost.


What was the reason some electrifications were removed after a while?


What can be a drawback of electrification of long distance freight trains?


Where can the issue of through traffic benefits occur?


What does the increasing demand for container traffic make companies use more often?


What is the other issue that comes to sight when using electrification system?

Additionally, there are issues of connections between different electrical services, particularly connecting intercity lines with sections electrified for commuter traffic, but also between commuter lines built to different standards. This can cause electrification of certain connections to be very expensive simply because of the implications on the sections it is connecting. Many lines have come to be overlaid with multiple electrification standards for different trains to avoid having to replace the existing rolling stock on those lines. Obviously, this requires that the economics of a particular connection must be more compelling and this has prevented complete electrification of many lines. In a few cases, there are diesel trains running along completely electrified routes and this can be due to incompatibility of electrification standards along the route.


Why the commuter lines built to different standards can cause be complicated?


What is the solution many lines came up with in order to avoid replacing present rolling stock?


Why are disel trains still used on electrified routes?


Which of two can be more efficiently electricified?

Central station electricity can often be generated with higher efficiency than a mobile engine/generator. While the efficiency of power plant generation and diesel locomotive generation are roughly the same in the nominal regime, diesel motors decrease in efficiency in non-nominal regimes at low power while if an electric power plant needs to generate less power it will shut down its least efficient generators, thereby increasing efficiency. The electric train can save energy (as compared to diesel) by regenerative braking and by not needing to consume energy by idling as diesel locomotives do when stopped or coasting. However, electric rolling stock may run cooling blowers when stopped or coasting, thus consuming energy.


How can electric power plant become more power efficient?


How can electric train be more energy efficient?


Which type of train continues to use energy while coasting or being stopped?


What causes electric trains to waste energy?


Can renewable source of electricity be used in mobile power plants?

Energy sources unsuitable for mobile power plants, such as nuclear power, renewable hydroelectricity, or wind power can be used. According to widely accepted global energy reserve statistics, the reserves of liquid fuel are much less than gas and coal (at 42, 167 and 416 years respectively). Most countries with large rail networks do not have significant oil reserves and those that did, like the United States and Britain, have exhausted much of their reserves and have suffered declining oil output for decades. Therefore, there is also a strong economic incentive to substitute other fuels for oil. Rail electrification is often considered an important route towards consumption pattern reform. However, there are no reliable, peer-reviewed studies available to assist in rational public debate on this critical issue, although there are untranslated Soviet studies from the 1980s.


What is the recent incentive in order to overcome oil scarcity?


What type of natural resources is more scarce?


What research can be used in the future if translated?


What type of trains became more energy-efficient in the former Soviet Union?

In the former Soviet Union, electric traction eventually became somewhat more energy-efficient than diesel. Partly due to inefficient generation of electricity in the USSR (only 20.8% thermal efficiency in 1950 vs. 36.2% in 1975), in 1950 diesel traction was about twice as energy efficient as electric traction (in terms of net tonne-km of freight per kg of fuel). But as efficiency of electricity generation (and thus of electric traction) improved, by about 1965 electric railways became more efficient than diesel. After the mid 1970s electrics used about 25% less fuel per ton-km. However diesels were mainly used on single track lines with a fair amount of traffic so that the lower fuel consumption of electrics may be in part due to better operating conditions on electrified lines (such as double tracking) rather than inherent energy efficiency. Nevertheless, the cost of diesel fuel was about 1.5 times more (per unit of heat energy content) than that of the fuel used in electric power plants (that generated electricity), thus making electric railways even more energy-cost effective.


What year could be marked as year when electric railways more efficient than diesel ones?


How much fuel did electric train used less than diesel in the middle of 1970 in USSR?


What could be a factor of lower energy consumption for electric trains?


How much more expensive was diesel compare to electricity per unit?


What caused the energy efficiency to go up?

Besides increased efficiency of power plants, there was an increase in efficiency (between 1950 and 1973) of the railway utilization of this electricity with energy-intensity dropping from 218 to 124 kwh/10,000 gross tonne-km (of both passenger and freight trains) or a 43% drop. Since energy-intensity is the inverse of energy-efficiency it drops as efficiency goes up. But most of this 43% decrease in energy-intensity also benefited diesel traction. The conversion of wheel bearings from plain to roller, increase of train weight, converting single track lines to double track (or partially double track), and the elimination of obsolete 2-axle freight cars increased the energy-efficiency of all types of traction: electric, diesel, and steam. However, there remained a 12–15% reduction of energy-intensity that only benefited electric traction (and not diesel). This was due to improvements in locomotives, more widespread use of regenerative braking (which in 1989 recycled 2.65% of the electric energy used for traction,) remote control of substations, better handling of the locomotive by the locomotive crew, and improvements in automation. Thus the overall efficiency of electric traction as compared to diesel more than doubled between 1950 and the mid-1970s in the Soviet Union. But after 1974 (thru 1980) there was no improvement in energy-intensity (wh/tonne-km) in part due to increasing speeds of passenger and freight trains.


What type of locomotives got improved during 1950-1973 in Soviet Union?


How much of energy was saved and re-used due to regenerative braking in 1989?


Was there an energy efficiency improvement in the period 1974 through 1980?


Elimination of what helped the efficiency of diesel traction to go up?


How many people speak Spanish as a first or second language in the United States?

The Spanish language is the second most spoken language in the United States. There are 45 million Hispanophones who speak Spanish as a first or second language in the United States, as well as six million Spanish language students. Together, this makes the United States of America the second largest Hispanophone country in the world after Mexico, and with the United States having more Spanish-speakers than Colombia and Spain (but fewer first language speakers). Spanish is the Romance language and the Indo-European language with the largest number of native speakers in the world. Roughly half of all American Spanish-speakers also speak English "very well," based on their self-assessment in the U.S. Census.


What other language is often spoken in the United states?


How many Spanish speaking students are there in the United States?


How old is the Spanish language in the United States?

The Spanish language has been present in what is now the United States since the 16th and 17th centuries, with the arrival of Spanish colonization in North America that would later become the states of Florida, Texas, Colorado, New Mexico, Arizona, Nevada, Utah, and California. The Spanish explorers explored areas of 42 future U.S. states leaving behind a varying range of Hispanic legacy in the North American continent. Additionally, western regions of the Louisiana Territory were under Spanish rule between 1763 to 1800, after the French and Indian War, further extending the Spanish influence throughout modern-day United States of America.


Where in the United States did the Spanish explore?


Did the Spanish conquer land in the United States?


Do the Spanish have a legacy in America from their forefathers?


Spanish was the language spoken by the first permanent European settlers in North America. Spanish arrived in the territory of the modern United States with Ponce de León in 1513. In 1565, the Spaniards, by way of Juan Ponce de León, founded St. Augustine, Florida, and as of the early 1800s, it became the oldest continuously occupied European settlement in the continental United States. The oldest city in all of the U.S. territory, as of 1898, is San Juan, capital of Puerto Rico, where Juan Ponce De León was its first governor


Where is the oldest settlement in America?


What is the oldest city of the United States territory?


In 1821, after Mexico's War of Independence from Spain, Texas was part of the United Mexican States as the state of Coahuila y Tejas. A large influx of Americans soon followed, originally with the approval of Mexico's president. In 1836, the now largely "American" Texans, fought a war of independence from the central government of Mexico and established the Republic of Texas. In 1846, the Republic dissolved when Texas entered the United States of America as a state. Per the 1850 U.S. census, fewer than 16,000 Texans were of Mexican descent, and nearly all were Spanish-speaking people (both Mexicans and non-Spanish European settlers who include German Texan) who were outnumbered (six-to-one) by English-speaking settlers (both Americans and other immigrant Europeans).[citation needed]


Was there a war between the Mexicans and the Texans?


Was Texas a primarily a Spanish speaking state?


After the Mexican War of Independence from Spain also, California, Nevada, Arizona, Utah, western Colorado and southwestern Wyoming became part of the Mexican territory of Alta California and most of New Mexico, western Texas, southern Colorado, southwestern Kansas, and Oklahoma panhandle were part of the territory of Santa Fe de Nuevo México. The geographical isolation and unique political history of this territory led to New Mexican Spanish differing notably from both Spanish spoken in other parts of the United States of America and Spanish spoken in the present-day United Mexican States.


When did other states become part of Mexico?


What states were part of Santa Fe de Nuevo


Why is there still Bilingual spoken in these states?


Why isn't the southwest Spanish speaking?

Through the force of sheer numbers, the English-speaking American settlers entering the Southwest established their language, culture, and law as dominant, to the extent it fully displaced Spanish in the public sphere; this is why the United States never developed bilingualism as Canada did. For example, the California constitutional convention of 1849 had eight Californio participants; the resulting state constitution was produced in English and Spanish, and it contained a clause requiring all published laws and regulations to be published in both languages. The constitutional convention of 1872 had no Spanish-speaking participants; the convention's English-speaking participants felt that the state's remaining minority of Spanish-speakers should simply learn English; and the convention ultimately voted 46-39 to revise the earlier clause so that all official proceedings would henceforth be published only in English.


Why didn't California officially become bilingual?


Did America try to make Puerto Rico an English speaking territory?

For decades, the U.S. federal government strenuously tried to force Puerto Ricans to adopt English, to the extent of making them use English as the primary language of instruction in their high schools. It was completely unsuccessful, and retreated from that policy in 1948. Puerto Rico was able to maintain its Spanish language, culture, and identity because the relatively small, densely populated island was already home to nearly a million people at the time of the U.S. takeover, all of those spoke Spanish, and the territory was never hit with a massive influx of millions of English speakers like the vast territory acquired from Mexico 50 years earlier.


How did America try to make Puerto Rico's language English?


Does Puerto Rico have many English speaking residents?


How did Puerto Rico stay a Spanish speaking territory?


At over 5 million, Puerto Ricans are easily the 2nd largest Hispanic group. Of all major Hispanic groups, Puerto Ricans are the least likely to be proficient in Spanish, but millions of Puerto Rican Americans living in the U.S. mainland nonetheless are fluent in Spanish. Puerto Ricans are natural-born U.S. citizens, and many Puerto Ricans have migrated to New York City, Orlando, Philadelphia, and other areas of the Eastern United States, increasing the Spanish-speaking populations and in some areas being the majority of the Hispanophone population, especially in Central Florida. In Hawaii, where Puerto Rican farm laborers and Mexican ranchers have settled since the late 19th century, 7.0 per cent of the islands' people are either Hispanic or Hispanophone or both.


Does Florida have a high Hispanic population?


Where are the biggest population of Puerto Ricans on the mainland?


Why did Cubans come to the United States?

Immigration to the United States of Spanish-speaking Cubans began because of Cuba's political instability upon achieving independence. The deposition of Fulgencio Batista's dictatorship and the ascension of Fidel Castro's government in 1959 increased Cuban immigration to the United States, hence there are some one million Cubans in the United States, most settled in southern and central Florida, while other Cubans live in the Northeastern United States; most are fluent in Spanish. In the city of Miami today Spanish is the first language mostly due to Cuban immigration.


What year did most Cubans start coming to America?


Is there a particular place where Cubans live and speak Spanish in the U.S.?


What other Spanish Speaking people come to America?

Likewise the migration of Spanish-speaking Nicaraguans also began as a result of political instability during the end of the 1970s and the 1980s. The uprising of the Sandinista revolution which toppled the Somoza dictatorship in 1979 caused many Nicaraguans to migrate particularly from those opposing the Sandinistas. Throughout the 1980s with the United States supported Contra War (or Contra-revolutionary war) which continued up until 1988, and the economic collapse of the country many more Nicaraguans migrated to the United States amongst other countries. The states of the United States where most Nicaraguans migrated to include Florida, California and Texas.


Why did the Nicaraguans come to America?


Where did Nicaraguans settle in America?


Was there a specific reason many Nicaraguans fled to the U.S.?


The exodus of Salvadorans was a result of both economic and political problems. The largest immigration wave occurred as a result of the Salvadoran Civil War in the 1980s, in which 20–30% of El Salvador's population emigrated. About 50%, or up to 500,000 of those who escaped headed to the United States, which was already home to over 10,000 Salvadorans, making Salvadorans Americans the fourth-largest Hispanic and Latino American group, after the Mexican-American majority, stateside Puerto Ricans, and Cubans.


What is the population of Salvadorans living in America?


Where do Salvadorans fall on the scale for Hispanic living in America?


Why did Central Americans flee to the U.S.?

As civil wars engulfed several Central American countries in the 1980s, hundreds of thousands of Salvadorans fled their country and came to the United States. Between 1980 and 1990, the Salvadoran immigrant population in the United States increased nearly fivefold from 94,000 to 465,000. The number of Salvadoran immigrants in the United States continued to grow in the 1990s and 2000s as a result of family reunification and new arrivals fleeing a series of natural disasters that hit El Salvador, including earthquakes and hurricanes. By 2008, there were about 1.1 million Salvadoran immigrants in the United States.


Are the Salvadorans a large population in the U.S.?


Is the Salvadoran population still growing?


How many Salvadorans are in America now?


When did the Venezuelans emigrate to the united states?

Until the 20th century, there was no clear record of the number of Venezuelans who emigrated to the United States. Between the 18th and early 19th centuries, there were many European immigrants who went to Venezuela, only to later migrate to the United States along with their children and grandchildren who born and/or grew up in Venezuela speaking Spanish. From 1910 to 1930, it is estimated that over 4,000 South Americans each year emigrated to the United States; however, there are few specific figures indicating these statistics. Many Venezuelans settled in the United States with hopes of receiving a better education, only to remain in there following graduation. They are frequently joined by relatives. However, since the early 1980s, the reasons for Venezuelan emigration have changed to include hopes of earning a higher salary and due to the economic fluctuations in Venezuela which also promoted an important migration of Venezuelan professionals to the US.


Does Venezuela have immigrates from other countries?


Do Venezuelans still come to America for the same reasons as they did before?


In the 2000s, more Venezuelans opposing the economic and political policies of president Hugo Chávez migrated to the United States (mostly to Florida, but New York City and Houston are other destinations). The largest concentration of Venezuelans in the United States is in South Florida, especially the suburbs of Doral and Weston. Other main states with Venezuelan American populations are, according to the 1990 census, New York, California, Texas (adding their existing Hispanic populations), New Jersey, Massachusetts and Maryland. Some of the urban areas with a high Venezuelan community include Miami, New York City, Los Angeles, and Washington, D.C.


What areas of America did the Venezuelans settle in?


Are there any other areas of America Venezuelans settled in?


Where are the most populated city's Venezuelan live in?


Is there such a thing as bilingual state?

Although the United States has no de jure official language, English is the dominant language of business, education, government, religion, media, culture, civil society, and the public sphere. Virtually all state and federal government agencies and large corporations use English as their internal working language, especially at the management level. Some states, such as New Mexico, provide bilingual legislated notices and official documents, in Spanish and English, and other commonly used languages. By 2015, there was a trend that most Americans and American residents who are of Hispanic descent speak only English in the home.


Do American Hispanics speak English in the home?


Is there an official language of the United States?


Has some states like Arizona embraced their Mexican history?

The state (like its southwestern neighbors) has had close linguistic and cultural ties with Mexico. The state outside the Gadsden Purchase of 1853 was part of the New Mexico Territory until 1863, when the western half was made into the Arizona Territory. The area of the former Gadsden Purchase contained a majority of Spanish-speakers until the 1940s, although the Tucson area had a higher ratio of anglophones (including Mexican Americans who were fluent in English); the continuous arrival of Mexican settlers increases the number of Spanish-speakers.


Has New Mexico had a majority of Spanish speaking natives.


Are Arizona and New Mexico residents speaking Spanish or English?


Does New Mexico have an official language?

New Mexico is commonly thought to have Spanish as an official language alongside English because of its wide usage and legal promotion of Spanish in the state; however, the state has no official language. New Mexico's laws are promulgated bilingually in Spanish and English. Although English is the state government's paper working language, government business is often conducted in Spanish, particularly at the local level. Spanish has been spoken in the New Mexico-Colorado border and the contemporary U.S.–Mexico border since the 16th century.[citation needed]


What language is New Mexico's language written in?


How long has New Mexico been speaking Spanish?


Is New Mexico known for the Spanish language?


Why is New Mexico always an after thought in American -Spanish speaking society?

Because of its relative isolation from other Spanish-speaking areas over most of its 400-year existence, New Mexico Spanish, and in particular the Spanish of northern New Mexico and Colorado has retained many elements of 16th- and 17th-century Spanish and has developed its own vocabulary. In addition, it contains many words from Nahuatl, the language spoken by the ancient Aztecs of Mexico. New Mexican Spanish also contains loan words from the Pueblo languages of the upper Rio Grande Valley, Mexican-Spanish words (mexicanismos), and borrowings from English. Grammatical changes include the loss of the second person verb form, changes in verb endings, particularly in the preterite, and partial merging of the second and third conjugations.


Is New Mexico's language different than from other Spanish dialect


How does New Mexico's Spanish dialect differ?


Does New Mexico's language also include other dialect?


Does New Mexico also use language from the American language when spoken in Spanish?


In Texas, English is the state's de facto official language (though it lacks de jure status) and is used in government. However, the continual influx of Spanish-speaking immigrants increased the import of Spanish in Texas. Texas's counties bordering Mexico are mostly Hispanic, and consequently, Spanish is commonly spoken in the region. The Government of Texas, through Section 2054.116 of the Government Code, mandates that state agencies provide information on their websites in Spanish to assist residents who have limited English proficiency.


Are there exceptions to Texas official language?


How does Texas handle people who don't speak English, but live in Mexico?


How does this mandate help Spanish speaking residents?


What language, other than English, is spoken in the U.S.?

Spanish is currently the most widely taught non-English language in American secondary schools and of higher education. More than 1.4 million university students were enrolled in language courses in autumn of 2002 and Spanish is the most widely taught language in American colleges and universities with 53 percent of the total number of people enrolled, followed by French (14.4%), German (7.1%), Italian (4.5%), American Sign language (4.3%), Japanese (3.7%), and Chinese (2.4%) although the totals remain relatively small in relation to the total U.S population.


Are students taught Spanish in american schools?


How popular are Spanish language classes in the U.S,?


What other languages are popular among American students?


Are these other languages learned in the U.S. as popular as Spanish?


What political speaches are delivered in English and Spanish?

The State of the Union Addresses and other presidential speeches are translated to Spanish, following the precedent set by the Bill Clinton administration. Official Spanish translations are available at WhiteHouse.gov. Moreover, non-Hispanic American origin politicians fluent in Spanish-speak in Spanish to Hispanic majority constituencies. There are 500 Spanish newspapers, 152 magazines, and 205 publishers in the United States; magazine and local television advertising expenditures for the Hispanic market have increased much from 1999 to 2003, with growth of 58 percent and 43 percent, respectively.


Was this always the case in American political addresses?


Does Washington (government) operate in both languages (bilingual-Spanish?)


If someone is not bilingual and only speaks Spanish, how do they learn about current events?


Is the Hispanic population relevant to the American media?


Are there studies on Hispanic-American language?

Calvin Veltman undertook, for the National Center for Education Statistics and for the Hispanic Policy Development Project, the most complete study of English language adoption by Hispanophone immigrants. Mr Veltman's language shift studies document high bilingualism rates and subsequent adoption of English as the preferred language of Hispanics, particularly by the young and the native-born. The complete set of these studies' demographic projections postulates the near-complete assimilation of a given Hispanophone immigrant cohort within two generations. Although his study based itself upon a large 1976 sample from the Bureau of the Census (which has not been repeated), data from the 1990 Census tend to confirm the great Anglicization of the US Hispanic American origin population.


Is Calvin Veltman' relevant to today's Hispanic Americans?


Are there other similar findings similar to Calvin Veltman' for the modern age?


What is the oldest city in South Carolina?

Charleston is the oldest and second-largest city in the U.S. state of South Carolina, the county seat of Charleston County, and the principal city in the Charleston–North Charleston–Summerville Metropolitan Statistical Area. The city lies just south of the geographical midpoint of South Carolina's coastline and is located on Charleston Harbor, an inlet of the Atlantic Ocean formed by the confluence of the Ashley and Cooper Rivers, or, as is locally expressed, "where the Cooper and Ashley Rivers come together to form the Atlantic Ocean."


What county is Charleston, South Carolina located in?


Charleston Harbor is an inlet of what ocean?


What river mergers with the Cooper River to form Charleston Harbor?


Charleston Harbor is formed on what ocean?


What river merges with the Ashley River to from the Charleston Harbor?


Founded in 1670 as Charles Town in honor of King Charles II of England, Charleston adopted its present name in 1783. It moved to its present location on Oyster Point in 1680 from a location on the west bank of the Ashley River known as Albemarle Point. By 1690, Charles Town was the fifth-largest city in North America, and it remained among the 10 largest cities in the United States through the 1840 census. With a 2010 census population of 120,083 (and a 2014 estimate of 130,113), current trends put Charleston as the fastest-growing municipality in South Carolina. The population of the Charleston metropolitan area, comprising Berkeley, Charleston, and Dorchester Counties, was counted by the 2014 estimate at 727,689 – the third-largest in the state – and the 78th-largest metropolitan statistical area in the United States.


Charles Town was named after which king?


What was Charleston's population in 2010?


What year was Charleston originally founded?


What was the originally name of Charleston?


How many people lived in Charleston in 2010?


How large is Charleston, South Carolina?

According to the United States Census Bureau, the city has a total area of 127.5 square miles (330.2 km2), of which 109.0 square miles (282.2 km2) is land and 18.5 square miles (47.9 km2) is covered by water. The old city is located on a peninsula at the point where, as Charlestonians say, "The Ashley and the Cooper Rivers come together to form the Atlantic Ocean." The entire peninsula is very low, some is landfill material, and as such, frequently floods during heavy rains, storm surges, and unusually high tides. The city limits have expanded across the Ashley River from the peninsula, encompassing the majority of West Ashley as well as James Island and some of Johns Island. The city limits also have expanded across the Cooper River, encompassing Daniel Island and the Cainhoy area. North Charleston blocks any expansion up the peninsula, and Mount Pleasant occupies the land directly east of the Cooper River.


Which city blocks Charleston for expanding up the peninsula?


How much of Charleston is covered by water?


How of Charleston's total area is dry land?


What town occupies the land directly east of the Cooper River?


What season is the wettest in Charleston?

Charleston has a humid subtropical climate (Köppen climate classification Cfa), with mild winters, hot, humid summers, and significant rainfall all year long. Summer is the wettest season; almost half of the annual rainfall occurs from June to September in the form of thundershowers. Fall remains relatively warm through November. Winter is short and mild, and is characterized by occasional rain. Measurable snow (≥0.1 in or 0.25 cm) only occurs several times per decade at the most, with the last such event occurring December 26, 2010. However, 6.0 in (15 cm) fell at the airport on December 23, 1989, the largest single-day fall on record, contributing to a single-storm and seasonal record of 8.0 in (20 cm) snowfall.


In what form does half of Charleston's annual rainfall occur?


What season is characterized as short in Charleston?


What is Charleston's seasonal record of snowfall?


What season is considered short in Charleston?


What is the wettest season in Charleston?


Half of Charleston's annual rainfall occurs in what form?


How much snow did Charleston's Airport recieve on December, 23 1989?


What is hottest temperature recorded with Charleston's city limits?

The highest temperature recorded within city limits was 104 °F (40 °C), on June 2, 1985, and June 24, 1944, and the lowest was 7 °F (−14 °C) on February 14, 1899, although at the airport, where official records are kept, the historical range is 105 °F (41 °C) on August 1, 1999 down to 6 °F (−14 °C) on January 21, 1985. Hurricanes are a major threat to the area during the summer and early fall, with several severe hurricanes hitting the area – most notably Hurricane Hugo on September 21, 1989 (a category 4 storm). Dewpoint in the summer ranges from 67.8 to 71.4 °F (20 to 22 °C).


What was the lowest temperature ever recorded Charleston's city limit?


What type of storm is a major threat to Charleston in the summer and early fall?


What day did Charleston's airport hit the coldest day on record?


How many people lived in the Charleston=North Charleston Urban Area in 2010?

The Charleston-North Charleston-Summerville Metropolitan Statistical Area consists of three counties: Charleston, Berkeley, and Dorchester. As of the 2013 U.S. Census, the metropolitan statistical area had a total population of 712,239 people. North Charleston is the second-largest city in the Charleston-North Charleston-Summerville Metropolitan Statistical Area and ranks as the third-largest city in the state; Mount Pleasant and Summerville are the next-largest cities. These cities combined with other incorporated and unincorporated areas along with the city of Charleston form the Charleston-North Charleston Urban Area with a population of 548,404 as of 2010. The metropolitan statistical area also includes a separate and much smaller urban area within Berkeley County, Moncks Corner (with a 2000 population of 9,123).


What is the third largest city in South Carolina?


How many people lived in Moncks Corner in 2000?


Charleston and Berkeley is combined with what other county to form a metropolitan statistical area?


In which county is Moncks Corner located?


What era brought counties to South Carolina?

The traditional parish system persisted until the Reconstruction Era, when counties were imposed.[citation needed] Nevertheless, traditional parishes still exist in various capacities, mainly as public service districts. When the city of Charleston was formed, it was defined by the limits of the Parish of St. Philip and St. Michael, now also includes parts of St. James' Parish, St. George's Parish, St. Andrew's Parish, and St. John's Parish, although the last two are mostly still incorporated rural parishes.


Counties replaced what system in South Carolina?


What is the main use of the parish system nowadays?


The city of Charleston is defined by the limits of the Parish of St. Michael and what other parish?


What other parish besides St. John's Parish is mostly an incorporated rural parish?