what are satellites ?

A satellite is a moon, planet or machine that orbits a planet or star. For example, Earth is a satellite because it orbits the sun. Likewise, the moon is a satellite because it orbits Earth. Usually, the word "satellite" refers to a machine that is launched into space and moves around Earth or another body in space.Earth and the moon are examples of natural satellites. Thousands of artificial, or man-made, satellites orbit Earth. Some take pictures of the planet that help meteorologists predict weather and track hurricanes. Some take pictures of other planets, the sun, black holes, dark matter or faraway galaxies. These pictures help scientists better understand the solar system and universe. There are many types of satellites such as communication satellites, navigation satellites and many more.

THE USES OF SATELLITES

TELEVISION-Satellites send television signals directly to homes, but they also are the backbone of cable and network TV.

TELEPHONE-Satellites provide in-flight phone communications on airplanes, and are often the main conduit of voice communication for rural areas and areas where phone lines are damaged after a disaster.

NAVIGATIONS-Satellite-based navigation systems like the Navstar Global Positioning Systems (known colloquially as GPS) enable anyone with a handheld receiver to determine her location to within a few meters.

BUSINESS + FINANCE-This is an important tool, allowing big manufacturing companies and department stores to perform inventory management, provide instant credit card authorization and automated teller banking services to even small towns, pay-at-the-pump gas at freeway gas stations, and video conferencing for international corporations.

WEATHER-Satellites provide meteorologists with the ability to see weather on a global scale, allowing them to follow the effects of phenomena like volcanic eruptions and burning gas and oil fields, to the development of large systems like hurricanes and El Nio.

CLIMATE AND ENVIRONMENTAL MONITORING-Monitor ocean temperatures and prevailing currents-Measure the changing sizes of glaciers

SAFETY-Monitor ocean and wind currents as well as the extent of forest fires, oil spills, and airborne pollution

LAND STEWARDSHIP-Detect underground water and mineral sources-Monitor the transfer of nutrients and contaminants from land into waterwaysMeasure land and water temperatures, the growth of algae in seas, and the erosion of topsoil from land.

DEVELOPMENT-Provides remote populations access toeducation and to medical expertise that would otherwise not reach them

SPACE SCIENCE -Satellite telescopes have been critical to understanding phenomena like pulsars and black holes as well as measuring the age of the universe.The Hubble Space Telescope is arguably the most valuable astronomical tool ever built!