The speed of light has become important in high-frequency trading, where traders seek to gain minute advantages by delivering their trades to exchanges fractions of a second ahead of other traders. For example, traders have been switching to microwave communications between trading hubs, because of the advantage which microwaves travelling at near to the speed of light in air, have over fibre optic signals which travel 3040% slower at the speed of light through glass.
Until the early modern period, it was not known whether light travelled instantaneously or at a very fast finite speed. The first extant recorded examination of this subject was in ancient Greece. The ancient Greeks, Muslim scholars, and classical European scientists long debated this until Rmer provided the first calculation of the speed of light. Einstein's Theory of Special Relativity concluded that the speed of light is constant regardless of one's frame of reference. Since then, scientists have provided increasingly accurate measurements.
In the second half of the 20th century much progress was made in increasing the accuracy of measurements of the speed of light, first by cavity resonance techniques and later by laser interferometer techniques. These were aided by new, more precise, definitions of the metre and second. In 1950, Louis Essen determined the speed as 299792.51 km/s, using cavity resonance. This value was adopted by the 12th General Assembly of the Radio-Scientific Union in 1957. In 1960, the metre was redefined in terms of the wavelength of a particular spectral line of krypton-86, and, in 1967, the second was redefined in terms of the hyperfine transition frequency of the ground state of caesium-133.
In 1972, using the laser interferometer method and the new definitions, a group at the US National Bureau of Standards in Boulder, Colorado determined the speed of light in vacuum to be c = 299792456.21.1 m/s. This was 100 times less uncertain than the previously accepted value. The remaining uncertainty was mainly related to the definition of the metre. As similar experiments found comparable results for c, the 15th General Conference on Weights and Measures in 1975 recommended using the value 299792458 m/s for the speed of light.
There are 127 known mammalian species in Sulawesi. A large percentage of these mammals, 62% (79 species) are endemic, meaning that they are found nowhere else in Indonesia or the world. The largest native mammals in Sulawesi are the two species of anoa or dwarf buffalo. Other mammalian species inhabiting Sulawesi are the babirusas, which are aberrant pigs, the Sulawesi palm civet, and primates including a number of tarsiers (the spectral, Dian's, Lariang and pygmy species) and several species of macaque, including the crested black macaque, the moor macaque and the booted macaque. Although virtually all Sulawesi's mammals are placental, and generally have close relatives in Asia, several species of cuscus, marsupials of Australasian origin, are also present.
Sulawesi is home to a large number of endemic rodent genera. Rodent genera exclusively endemic to Sulawesi and immediately adjacent islands (such as the Togian Islands, Buton Island, and Muna Island) are Bunomys, Echiothrix, Hyosciurus, Margaretamys, Paucidentomys, Prosciurillus, Taeromys, Tateomys, and Waiomys, as well as the single-species genera Eropeplus, Hyorhinomys, Melasmothrix, Paruromys, Rubrisciurus, and Sommeromys. All belong to the family Muridae except for the genera Hyosciurus, Prosciurillus, and Rubrisciurus, which belong to the family Sciuridae.