Question: When did the spacecraft that detected storms on Neptune leave our solar system?

title: Solar power in Germany
text: Solar power in Germany consists almost exclusively of photovoltaics (PV) and accounted for an estimated 6.2 to 6.9 percent of the country's net - electricity generation in 2016. About 1.5 million photovoltaic systems were installed around the country in 2014, ranging from small rooftop systems, to medium commercial and large utility - scale solar parks. Germany's largest solar farms are located in Meuro, Neuhardenberg, and Templin with capacities over 100 MW. Solar heating does not use solar energy for power generation and is therefore not included in this article.

title: Solar energy
text: The common features of passive solar architecture are orientation relative to the Sun, compact proportion (a low surface area to volume ratio), selective shading (overhangs) and thermal mass. When these features are tailored to the local climate and environment they can produce well-lit spaces that stay in a comfortable temperature range. Socrates' Megaron House is a classic example of passive solar design. The most recent approaches to solar design use computer modeling tying together solar lighting, heating and ventilation systems in an integrated solar design package. Active solar equipment such as pumps, fans and switchable windows can complement passive design and improve system performance.

title: Solar energy
text: Solar hot water systems use sunlight to heat water. In low geographical latitudes (below 40 degrees) from 60 to 70% of the domestic hot water use with temperatures up to 60 °C can be provided by solar heating systems. The most common types of solar water heaters are evacuated tube collectors (44%) and glazed flat plate collectors (34%) generally used for domestic hot water; and unglazed plastic collectors (21%) used mainly to heat swimming pools.

title: Solar energy
text: It is an important source of renewable energy and its technologies are broadly characterized as either passive solar or active solar depending on the way they capture and distribute solar energy or convert it into solar power. Active solar techniques include the use of photovoltaic systems, concentrated solar power and solar water heating to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.

title: Fierbinți Solar Park
text: Fierbinţi Solar Park, a large thin-film photovoltaic (PV) power system, is being built on a 4 ha plot of land near the Fierbinți-Târg commune in Romania. The power plant will be a 10-megawatt solar power system using state-of-the-art thin film technology, and should be finished by the end of 2012. The solar park is expected to supply 4,000 MWh of electricity per year.

title: Mercury (planet)
text: Mercury is the smallest and innermost planet in the Solar System. Its orbital period around the Sun of 88 days is the shortest of all the planets in the Solar System. It is named after the Roman deity Mercury, the messenger to the gods.

title: Nebular hypothesis
text: Nebular hypothesis: The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems). It suggests that the Solar System formed from nebulous material. The theory was developed by Immanuel Kant and published in his Allgemeine Naturgeschichte und Theorie des Himmels (``Universal Natural History and Theory of the Heavens ''), published in 1755. Originally applied to the Solar System, the process of planetary system formation is now thought to be at work throughout the Universe. The widely accepted modern variant of the nebular hypothesis is the solar nebular disk model (SNDM) or solar nebular model. It offered explanations for a variety of properties of the Solar System, including the nearly circular and coplanar orbits of the planets, and their motion in the same direction as the Sun's rotation. Some elements of the original nebular hypothesis are echoed in modern theories of planetary formation, but most elements have been superseded.

title: Wonders of the Solar System
text: Wonders of the Solar System is a 2010 television series co-produced by the BBC and Science Channel, and hosted by physicist Brian Cox. "Wonders of the Solar System" was first broadcast in the United Kingdom on BBC Two on 7 March 2010. The series comprises five episodes, each of which focuses on an aspect of the Solar System and features a 'wonder' relevant to the theme. The series was described as one of the most successful to appear on BBC Two in recent years. An accompanying book with the same name was also published.

title: The SpongeBob SquarePants Movie
text: That night, SpongeBob goes to his favorite restaurant, Goofy Goober's, where he drowns his sorrows in ice cream with his best friend Patrick Star. Elsewhere, Mr. Krabs' business rival Plankton steals King Neptune's crown, leaving false evidence to frame Mr. Krabs for the crime, and sends the crown to Shell City, a distant, mysterious land from which no fish has returned. The next morning, Neptune barges into the Krusty Krab 2 and threatens Mr. Krabs for his alleged thievery. SpongeBob later arrives and chastises Krabs under the influence of an ice cream headache, but seeing his boss's life is at risk, he promises Neptune that he will retrieve the crown from Shell City. Neptune freezes Krabs and orders SpongeBob to return with the crown in six days for him to spare Krabs' life. Neptune's sympathetic daughter, Princess Mindy, gives SpongeBob a Bag of Winds so that they can return from Shell City once they find the crown. SpongeBob and Patrick leave for Shell City in the Patty Wagon, a car shaped like a Krabby Patty.

title: Kuiper belt
text: The Kuiper belt (/ ˈkaɪpər / or Dutch pronunciation: ('kœy̯pər)), occasionally called the Edgeworth -- Kuiper belt, is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune (at 30 AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger -- 20 times as wide and 20 to 200 times as massive. Like the asteroid belt, it consists mainly of small bodies or remnants from when the Solar System formed. While many asteroids are composed primarily of rock and metal, most Kuiper belt objects are composed largely of frozen volatiles (termed ``ices ''), such as methane, ammonia and water. The Kuiper belt is home to three officially recognized dwarf planets: Pluto, Haumea and Makemake. Some of the Solar System's moons, such as Neptune's Triton and Saturn's Phoebe, may have originated in the region.

title: Halimede (moon)
text: Halimede is about 62 kilometers in diameter (assuming an albedo of 0.04) and appears neutral (grey) in the visible light. Given the very similar colour of the satellite to that of Nereid together with the high probability (41%) of collision in the past lifespan of the Solar System, it has been suggested that the satellite could be a fragment of Nereid.Halimede, like many of the outer satellites of Neptune, is named after one of the Nereids, the fifty daughters of Nereus and Doris. Before the announcement of its name on February 3, 2007 (IAUC 8802), Halimede was known by the provisional designation S/2002 N 1.

title: Neptune
text: 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.

title: Neptune Glacier
text: Neptune Glacier () is a glacier on the east coast of Alexander Island, Antarctica, 12 nautical miles (22 km) long and 4 nautical miles (7 km) wide, flowing east into George VI Sound and the George VI Ice Shelf to the south of Triton Point. Although Neptune Glacier is not located within the mountain range Planet Heights, the glaciers name derives from the mountain range along with many other nearby glaciers named after planets of the Solar System. There are also other nearby landforms named in association with these glaciers. The glacier was first sighted from the air by Lincoln Ellsworth on November 23, 1935, and roughly mapped from photos obtained on that flight by W.L.G. Joerg. The mouth of the glacier was positioned in 1936 by the British Graham Land Expedition (BGLE). Named by the United Kingdom Antarctic Place-Names Committee (UK-APC) for the planet Neptune following a Falkland Islands Dependencies Survey (FIDS) survey in 1949. The head of the glacier was mapped from air photos taken by the Ronne Antarctic Research Expedition (RARE), 1947–48, by Searle of the FIDS in 1960.

title: Voyager 2
text: On August 30, 2007, Voyager 2 passed the termination shock and then entered into the heliosheath, approximately 1 billion miles (1.6 billion km) closer to the Sun than Voyager 1 did. This is due to the interstellar magnetic field of deep space. The southern hemisphere of the Solar System's heliosphere is being pushed in.

title: Neptune
text: The average distance between Neptune and the Sun is 4.5 billion km (about 30.1 astronomical units (AU)), and it completes an orbit on average every 164.79 years, subject to a variability of around ±0.1 years. The perihelion distance is 29.81 AU; the aphelion distance is 30.33 AU.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.The elliptical orbit of Neptune is inclined 1.77° compared to that of Earth.

title: Neptune
text: 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.

title: Neptune
text: 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 13 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 the "Hubble Space Telescope" and large ground-based telescopes with adaptive optics has recently allowed for additional detailed observations from afar.

title: Exploration of Neptune
text: The exploration of Neptune has only begun with one spacecraft, Voyager 2 in 1989. Currently there are no approved future missions to visit the Neptunian system. NASA, ESA and also independent academic groups have proposed future scientific missions to visit Neptune. Some mission plans are still active, while others have been abandoned or put on hold.

title: Voyager 2
text: Following a mid-course correction in 1987, Voyager 2's closest approach to Neptune occurred on August 25, 1989. Through repeated computerized test simulations of trajectories through the Neptunian system conducted in advance, flight controllers determined the best way to route Voyager 2 through the Neptune-Triton system. Since the plane of the orbit of Triton is tilted significantly with respect to the plane of the ecliptic, through mid-course corrections, Voyager 2 was directed into a path about 4950 kilometers (3000 mi) above the north pole of Neptune. Five hours after Voyager 2 made its closest approach to Neptune, it performed a close fly-by of Triton, the larger of Neptune's two originally known moons, passing within about 40,000 kilometers (25,000 mi).Voyager 2 discovered previously unknown Neptunian rings, and confirmed six new moons: Despina, Galatea, Larissa, Proteus, Naiad and Thalassa. While in the neighborhood of Neptune, Voyager 2 discovered the "Great Dark Spot", which has since disappeared, according to observations by the Hubble Space Telescope. The Great Dark Spot was later hypothesized to be a region of clear gas, forming a window in the planet's high-altitude methane cloud deck.With the decision of the International Astronomical Union to reclassify Pluto as a dwarf planet in 2006, the flyby of Neptune by Voyager 2 in 1989 became the point when every known planet in the Solar System had been visited at least once by a space probe.

title: Neptune
text: 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.

Answer: August 30, 2007