An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A solid bounded by a plane and the surface generated by a straight line which always touches a simple closed curve on the plane and passes through a fixed point not on the plane.

L. conus "a wedge, peak, cone," from Gk. konos "cone, spinning top, pine cone," from PIE base *ko(n)- "to sharpen."

Maxrut from Ar.

The set of all points in a → space-time diagram that are reached by signals travelling from a specified point at the speed of light.

→ future; → light; → cone.

The set of all directions in which a light signal can travel toward an event (past light cone) or from an event (future light cone).

→ light; → cone.

The cone that confines the pressure disturbance created by a → supersonic object moving in a → compressible medium.

→ Mach number; → cone.

A cone-shaped shadow cast by Earth or the Moon pointing away from the Sun. The dark inner portion of the shadow cone is called the → umbra. The lighter outer portion of the shadow is called the → penumbra. Its extension is called the → antumbra.

→ shadow; → cone.