Radio

Radio is the use of radio waves is to carry information, such as sound, by systematically modulating some property of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.

Radio systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation (which can be frequency modulation or phase modulation). Radio systems also need an antenna to convert electric currents into radio waves, and vice versa. An antenna can be used for both transmitting and receiving. The electrical resonance of tuned circuits in radios allow individual stations to be selected. The electromagnetic wave is intercepted by a tuned receiving antenna. A radio receiver receives its input from an antenna and converts it into a form usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc. Radio frequencies occupy the range from a 3 kHz to 300 GHz, although commercially important uses of radio use only a small part of this spectrum.

Columbia

Columbia may refer to:

Places

In North America

Costa Rica

Coordinates: 10°N 84°W / 10°N 84°W / 10; -84

Costa Rica (ⁱ/ˌkoʊstə ˈriːkə/; Spanish: [ˈkosta ˈrika]; literally meaning, "Rich Coast"), officially the Republic of Costa Rica (Spanish: República de Costa Rica), is a country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west, the Caribbean Sea to the east, and Ecuador to the south of Cocos Island. It has a population of around 4.5 million, of whom nearly a quarter live in the metropolitan area of the capital and largest city, San José.

Costa Rica was sparsely inhabited by indigenous people before coming under Spanish rule in the 16th century. It remained a peripheral colony of the empire until independence as part of the short-lived First Mexican Empire, followed by membership in the United Provinces of Central America, from which it formally declared sovereignty in 1847. Since then, Costa Rica has remained among the most stable, prosperous, and progressive nations in Latin America. Following a brief but bloody civil war, it permanently abolished its army in 1949, becoming the first of only a few sovereign nations without a standing army.

Space Shuttle

The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated by the U.S. National Aeronautics and Space Administration (NASA), as part of the Space Shuttle program. Its official program name was Space Transportation System (STS), taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development. The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982. They were used on a total of 135 missions from 1981 to 2011, launched from the Kennedy Space Center (KSC) in Florida. Operational missions launched numerous satellites, interplanetary probes, and the Hubble Space Telescope (HST); conducted science experiments in orbit; and participated in construction and servicing of the International Space Station. The Shuttle fleet's total mission time was 1322 days, 19 hours, 21 minutes and 23 seconds.

Shuttle components included the Orbiter Vehicle (OV), a pair of recoverable solid rocket boosters (SRBs), and the expendable external tank (ET) containing liquid hydrogen and liquid oxygen. The Shuttle was launched vertically, like a conventional rocket, with the two SRBs operating in parallel with the OV's three main engines, which were fueled from the ET. The SRBs were jettisoned before the vehicle reached orbit, and the ET was jettisoned just before orbit insertion, which used the orbiter's two Orbital Maneuvering System (OMS) engines. At the conclusion of the mission, the orbiter fired its OMS to de-orbit and re-enter the atmosphere. The orbiter then glided as a spaceplane to a runway landing, usually at the Shuttle Landing Facility of KSC or Rogers Dry Lake in Edwards Air Force Base, California. After landing at Edwards, the orbiter was flown back to the KSC on the Shuttle Carrier Aircraft, a specially modified Boeing 747.

Columbia University

Columbia University (officially Columbia University in the City of New York) is a private, Ivy League, research university in Upper Manhattan, New York City. It was established in 1754 as King's College by royal charter of George II of Great Britain and is the oldest college in New York State as well as the fifth chartered institution of higher learning in the country, making Columbia one of nine colonial colleges founded before the Declaration of Independence. After the revolutionary war, King's College briefly became a state entity, and was renamed Columbia College in 1784. A 1787 charter placed the institution under a private board of trustees before it was renamed Columbia University in 1896 when the campus was moved from Madison Avenue to its current location in Morningside Heights occupying land of 32 acres (13 ha). Columbia is one of the fourteen founding members of the Association of American Universities, and was the first school in the United States to grant the M.D. degree.