Parabola

a plane curve traced out by a point moving so that its distance from a fixed point (focus) is equal to its perpendicular distance from a fixed straight line (directrix). It is also the curve made by cutting a cone with a flat plane that is parallel to the side of the cone that slopes. Mirrors with a parabolic shape are used in searchlights and telescopes because incoming parallel rays of light are reflectd onto the focus. This property is used in a telescope, and thus the reverse applies in searchlights.

Taken from Dictionary of Science

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In mathematics, the parabola (pronounced /pəˈræbələ/, from the Greek παραβολή) is a conic section, the intersection of a right circular conical surface and a plane parallel to a generating straight line of that surface. Given a point (the focus) and a corresponding line (the directrix) on the plane, the locus of points in that plane that are equidistant from them is a parabola.

The parabola has many important applications, from automobile headlight reflectors to the design of ballistic missiles. They are frequently used in physics, engineering, and many other areas.

Taken from Wikipedia

Galactic Plane

the plane which passes through the centre of the MILKY WAY, as far as that can be determined.

Taken from Dictionary of Science

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The plane in which the disk of the Milky Way Galaxy lies. By definition, one direction perpendicular to this plane is called above or north, and the opposite direction, also perpendicular to the galactic plane, is called below or south. From Earth, due galactic north is marked by the north galactic pole, which lies in Coma Berenices, near the bright star Arcturus, and due galactic south is marked by the south galactic pole, which lies in Sculptor.

Taken from The Internet ENCYCLOPEDIA OF SCIENCE