A satellite is any object that moves in a curved path around a planet. The moon is Earth's original, natural satellite, and there are many man-made (artificial) satellites, usually closer to Earth. The path a satellite follows is an orbit, which sometimes takes the shape of a circle.
To understand why satellites move this way, we must revisit our friend Newton. Newton proposed that a force -- gravity -- exists between any two objects in the universe. If it weren't for this force, a satellite in motion near a planet would continue in motion at the same speed and in the same direction -- a straight line. This straight-line inertial path of a satellite, however, is balanced by a strong gravitational attraction directed toward the center of the planet.
hot hotter the hottest
fat fatter the fattest
great greater the greatest
happy happier the happiest
nasty nastier the nastiest
expensive more expensive the most expensive
comfortable more comfortable the most comfortable
good better the best
bad worse the worst
difficult more difficult the most difficult
interesting more interesting the most interesting
wonderful more wonderful the most wonderful
serious more serious the most serious
beautiful more beautiful the most beautiful
big bigger the biggest
