Submarine

A submarine is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term most commonly refers to a large, crewed, autonomous vessel. It is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Used as an adjective in phrases such as submarine cable, "submarine" means "under the sea". The noun submarine evolved as a shortened form of submarine boat (and is often further shortened to sub). For reasons of naval tradition, submarines are usually referred to as "boats" rather than as "ships", regardless of their size.

Although experimental submarines had been built before, submarine design took off during the 19th century, and they were adopted by several navies. Submarines were first widely used during World War I (1914–1918), and now figure in many navies large and small. Military usage includes attacking enemy surface ships (merchant and military), submarines, aircraft carrier protection, blockade running, ballistic missile submarines as part of a nuclear strike force, reconnaissance, conventional land attack (for example using a cruise missile), and covert insertion of special forces. Civilian uses for submarines include marine science, salvage, exploration and facility inspection/maintenance. Submarines can also be modified to perform more specialized functions such as search-and-rescue missions or undersea cable repair. Submarines are also used in tourism, and for undersea archaeology.

Submarine (baseball)

In baseball, a submarine pitch is one in which the ball is released underhand, and often just above the ground, with the torso bent at a right angle and shoulders tilted so severely that they rotate around a nearly horizontal axis. (This is in stark contrast to an underhand pitch in softball in which the torso remains upright, the shoulders are level, and the hips do not rotate.)

The "upside down" release of the submariner causes balls to move differently from pitches generated by other arm slots. Gravity plays a significant role, for the submariner’s ball must be thrown considerably above the strike zone, after which it drops rapidly back through. The sinking motion of the submariner’s fastball is enhanced by forward rotation, in contradistinction to the overhand pitcher’s hopping backspin.

Submarine pitches are often the toughest for same-side batters to hit (i.e., a right-handed submarine pitcher is the more difficult for a right-handed batter to hit, and likewise for left-handed pitchers and batters). This is because the submariner’s spin is not perfectly level; the ball rotates forward and toward the pitching arm side, jamming same-sided hitters at the last moment, even as the ball drops rapidly through the zone.

Marine geology

Marine geology or geological oceanography is the study of the history and structure of the ocean floor. It involves geophysical, geochemical, sedimentological and paleontological investigations of the ocean floor and coastal zone. Marine geology has strong ties to physical oceanography.

Marine geological studies were of extreme importance in providing the critical evidence for sea floor spreading and plate tectonics in the years following World War II. The deep ocean floor is the last essentially unexplored frontier and detailed mapping in support of both military (submarine) objectives and economic (petroleum and metal mining) objectives drives the research.

Overview

The Ring of Fire around the Pacific Ocean with its attendant intense volcanism and seismic activity poses a major threat for disastrous earthquakes, tsunamis and volcanic eruptions. Any early warning systems for these disastrous events will require a more detailed understanding of marine geology of coastal and island arc environments.