- Italy (Italian: Italia [iˈtaːlja]), officially the Italian Republic or the Republic of Italy, is a country in Southern and Western Europe. Located in the middle of the Mediterranean Sea, it consists of a peninsula delimited by the Alps and surrounded by several islands; its territory largely coincides with the homonymous geographical region. Italy shares land borders with France, Switzerland, Austria, Slovenia and the enclaved microstates of Vatican City and San Marino. It has a territorial exclave in Switzerland, Campione, and some islands in the African Plate. Italy covers an area of 301,230 km2 (116,310 sq mi), with a population of about 60 million. It is the third-most populous member state of the European Union, the sixth-most populous country in Europe, and the tenth-largest country in the continent by land area. Italy’s capital and largest city is Rome.
- n-body problem (Wikipedia)
In physics, the n-body problem is the problem of predicting the individual motions of a group of celestial objects interacting with each other gravitationally. Solving this problem has been motivated by the desire to understand the motions of the Sun, Moon, planets, and visible stars. In the 20th century, understanding the dynamics of globular cluster star systems became an important n-body problem. The n-body problem in general relativity is considerably more difficult to solve due to additional factors like time and space distortions.