From Media Hex
ParabolaParabola, two-dimensional curve that matches the path a tossed object such as a ball follows. Each point on the curve is equally distant from a fixed point, called the focus, and a fixed straight line, known as the directrix. The very tip of a parabola is called the vertex.
Parabolas are important in astronomy andParabolas are important in astronomy and physical science. An object in space follows a parabolic orbit as it swings around a central mass if the object has just barely enough momentum to escape from the gravity of the central mass forever. An asteroid that followed such a path around the Sun would fly off into interstellar space, never to return. Parabolic mirrors (reflectors that have the shape of a parabola) reflect rays of light in parallel lines from a light source located at the mirror`s focus.
Such reflectors are used in automobile headlights and in searchlights. Parabolic mirrors also bring parallel rays of light to a focus. This type of reflector is therefore valuable in astronomical telescopes. Parabolic reflectors also are used as antennas in radio astronomy and radar.