Unlike latitude, longitude does not maintain a constant distance between degrees since meridians all come together at the poles and are far apart at the equator. This means people near the North or South Pole can cross many degrees of longitude by travelling a short distance. The time difference between longitudes is 4 minutes per degree. The distance between degrees of longitude is maximum at the equator.
Hilary Duff
Hilary Erhard Duff (often as Hilary Duff) (Born: September 28, 1987) is an American actress and singer. She got celebrity famous by being in the television program show' Lizzie McGuire she has gone onto a movie career, with roles in mainstream pictures. Among the movies she plays in are "Cheaper by the Dozen", "The Perfect Man", "A Cinderella Story", "Raise Your Voice", "Material Girls" and independent movies such as "War, Inc." and "Greta". Duff has also ventured into a music career as a pop musician, releasing 8 albums (for example "Most Wanted", "Dignity", "Metamorphosis", "Hilary Duff") and 15 music videos (for example "Reach Out", "With Love", "Stranger", "Wake Up", "So Yesterday", "Come Clean"). Lately she has also ventured into a fashion career as a designer for DKNY, with her new line "Femme for DKNY".
In June 2018, Duff and her boyfriend Matthew Koma announced that they are expecting a baby girl.
Oil platform
An oil platform is a large structure placed in the sea. It is used to drill for oil or natural gas at the bottom of the sea. The platform may be attached to the sea floor (stationary)or it might be movable(mobile).
In general, oil platforms are located on the continental shelf. As of 2006, drilling for resources up to 8km away from the platform was possible.
Continental shelf
A continental shelf is the part of the continent that is under water. The shelf was part of the land during the ice ages in the glacial periods, but under water in the interglacial periods. We are at present in an interglacial period.
Every continent is in the sea, like an island. Most of the island is above the water line, and we see it as a continent. Some of it though, is below the water line. Beyond the continental shelf, the bottom goes down to much greater depths.
The continental shelf is a shallow ocean. It varies in depth, up to 140 metres deep. It varies greatly in its width. At the leading edge of a moving continental plate there will be little or no shelf. The western edge of the Americas are an example. The shelf on a passive edge of a plate will be wide and shallow. The widest shelf is the Siberian shelf in the Arctic Ocean: it is 1500 km (930 miles) in width.
There have been, at some periods, shallow seas "inside" continents. These are called epicontinental seas. Much of present-day North America was covered by an epicontinental sea called the Sundance Sea during the Jurassic period. In the Cretaceous an even larger area was covered by the Western Interior Seaway.
Continental seas have the richest life of the oceans, more species and greater numbers than anywhere else. This is because it has both sunlight and nutrients for photosynthesis. This causes microscopic algae and cyanobacteria to bloom, and then animals eat the phytoplankton. Most of the nutrients in the oceans are washed down from the continents by rivers. In particular, the continents are almost the only source for some key elements such as iron. The lack of nutrients away from continents explains why so much of the Pacific Ocean is almost barren of life, and why the shelves are so rich in life.
The shelf usually ends at a point of decreasing slope (called the shelf break). The sea floor below the break is the continental slope. The character of the shelf changes dramatically at the shelf break, where the continental slope begins. With a few exceptions, the shelf break is located at a remarkably uniform depth of roughly ; this is likely a hallmark of past ice ages, when sea level was lower than it is now.
Mariana Trench
The Mariana Trench is the deepest known submarine trench. It is also the deepest known location on Earth itself. It lies south and east of the Mariana Islands, and has a depth up to 10,971 m (7 miles). The western end of the trench is near Guam.
The trench is about 2,550 kilometres (1,580 miles) long but has a mean width of only 69 kilometres (43 miles).
The deepest part of the trench is known as the Challenger Deep. It is named after the British Royal Navy survey ship "HMS Challenger", whose expedition of 1872–76 made the first recordings of its depth.
A 2009 sonar mapping of the Challenger Deep from the "Kilo Moana" found a spot with a depth of (6.82 miles). The sonar system has an accuracy of better than 0.2% of water depth. <ref name="Daily reports for R/V KILO MOANA"></ref><ref name="Scientic Equipment aboard the R/V KILO MOANA"></ref> Water pressure is more than a thousand times as great as at the surface.
The Challenger Deep has been reached four times by submersibles, namely the manned bathyscaphe "Trieste" on 23 January 1960, the unmanned robotic deep-sea probes "Kaiko" (Japanese) in 1995 and "Nereus" (U.S.) in 2009, and by James Cameron in the Deepsea Challenger on 26 March, 2012. Cameron was able to film a 3D movie of the bottom of the trench.
The HMS "Challenger" expedition found radiolaria in the two dredged samples taken when the Challenger Deep was first discovered.
On their 1960 descent, the crew of the "Trieste" noted that the floor consisted of diatomaceous ooze and reported observing "some type of flatfish, resembling a sole, about 1 foot long and 6 inches across" lying on the seabed. The report has since been questioned, with suggestions that it may have been a sea cucumber. The video camera on board the "Kaiko" probe spotted a sea cucumber, a scale worm and a shrimp at the bottom. At the bottom of the Challenger deep, the "Nereus" probe spotted one polychaete worm about an inch long.
An analysis of the sediment samples collected by "Kaiko" found large numbers of simple organisms at .
The overwhelming majority of the organisms collected were simple, soft-shelled foraminifera (432 species according to National Geographic).
Eighty-five percent of the specimens were organic, soft-shelled forams. This is unusual compared to samples of sediment from other deep-sea environments, where the percentage of organic-walled foraminifera ranges from 5% to 20%. As small organisms with hard, calcareous shells have trouble growing at extreme depths because of the high solubility of calcium carbonate in the pressurized water, scientists theorize that the preponderance of soft-shelled organisms in the Challenger Deep may have resulted from survivors of the biosphere present when the Challenger Deep was shallower than it is now.
The trench is one of the results of a large boundary where two oceanic tectonic plates have converged (collided).
At the boundary, the western edge of the Pacific Plate is subducted beneath the small Mariana Plate. Because the Pacific plate is the largest of all the tectonic plates on Earth, crustal material at its western edge has had up to 170 million years to compact and become very dense; hence its great height-difference relative to the higher-riding Mariana Plate, at the point where the Pacific Plate crust is subducted. This deep area is the Mariana trench proper. The movement of these plates is also responsible for the formation of the Mariana Islands.
Mariana Islands
The Mariana Islands (also the Marianas; up to the early 20th century sometimes called "Islas de los Ladrones" meaning "Islands of Thieves") are a group of islands made up by the summits of 15 volcanic mountains in the western Pacific Ocean.
They are the southern part of a seamount range that goes on for 1,565 miles (2,519 km) from Guam to near Japan. The Marianas are the northernmost islands of a larger island group called Micronesia. The Marianas have a total land area of 396 square miles (1026 km²) and are composed of two administrative units: