Tahiti is the largest island in the Windward group of French Polynesia (an overseas country of the French Republic), located in the archipelago of the Society Islands in the southern Pacific Ocean. It is the economic, cultural and political centre of French Polynesia. The island was formed from volcanic activity and is high and mountainous with surrounding coral reefs. The population is 178,133 (2007 census), making it the most populous island of French Polynesia and accounting for 68.6% of the group's total population. Tahiti was formerly known as Otaheite.
The capital, Papeete, is located on the northwest coast with the only international airport in the region, Faa'a International Airport, situated 5 km (3.1 mi) from the town centre. Tahiti was originally settled by Polynesians between CE 300 and 800. They comprise about 70% of the island's population with the rest made up of Europeans, Chinese and those of mixed heritage. The island was proclaimed a colony of France in 1880 although it was not until 1946 that the indigenous Tahitians were legally authorised to be French citizens. French is the only official language although the Tahitian language (Reo Maohi) is widely spoken. It was part of the Kingdom of Tahiti until its annexation by France in 1880.
In physics a wave is a disturbance or oscillation that travels through space and matter, accompanied by a transfer of energy. Wave motion transfers energy from one point to another, often with no permanent displacement of the particles of the medium—that is, with little or no associated mass transport. They consist, instead, of oscillations or vibrations around almost fixed locations. Waves are described by a wave equation which sets out how the disturbance proceeds over time. The mathematical form of this equation varies depending on the type of wave.
There are two main types of waves. Mechanical waves propagate through a medium, and the substance of this medium is deformed. The deformation reverses itself owing to restoring forces resulting from its deformation. For example, sound waves propagate via air molecules colliding with their neighbors. When air molecules collide, they also bounce away from each other (a restoring force). This keeps the molecules from continuing to travel in the direction of the wave.
The second main type of wave, electromagnetic waves, do not require a medium. Instead, they consist of periodic oscillations of electrical and magnetic fields generated by charged particles, and can therefore travel through a vacuum. These types of waves vary in wavelength, and include radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.