Question: 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.
Is there an answer to this question: When was Neptune first observed?

Answer: 23 September 1846

Question: In Mesoamerica, a similar set of events (i.e., crop domestication and sedentary lifestyles) occurred by around 4500 BC, but possibly as early as 11,00010,000 BC. These cultures are usually not referred to as belonging to the Neolithic; in America different terms are used such as Formative stage instead of mid-late Neolithic, Archaic Era instead of Early Neolithic and Paleo-Indian for the preceding period. The Formative stage is equivalent to the Neolithic Revolution period in Europe, Asia, and Africa. In the Southwestern United States it occurred from 500 to 1200 C.E. when there was a dramatic increase in population and development of large villages supported by agriculture based on dryland farming of maize, and later, beans, squash, and domesticated turkeys. During this period the bow and arrow and ceramic pottery were also introduced.
Is there an answer to this question: When was there a dramatic increase in turkeys?

Answer: unanswerable

Question: The Polish nobility enjoyed many rights that were not available to the noble classes of other countries and, typically, each new monarch conceded them further privileges. Those privileges became the basis of the Golden Liberty in the PolishLithuanian Commonwealth. Despite having a king, Poland was called the nobility's Commonwealth because the king was elected by all interested members of hereditary nobility and Poland was considered to be the property of this class, not of the king or the ruling dynasty. This state of affairs grew up in part because of the extinction of the male-line descendants of the old royal dynasty (first the Piasts, then the Jagiellons), and the selection by the nobility of the Polish king from among the dynasty's female-line descendants.
Is there an answer to this question: WHy did the state affairs partly grow up on?

Answer: the extinction of the male-line descendants of the old royal dynasty

Question: Slavic studies began as an almost exclusively linguistic and philological enterprise. As early as 1833, Slavic languages were recognized as Indo-European.
Is there an answer to this question: When were Slavic languages recognized as Indo-European?

Answer:
As early as 1833