See conic.
The ratio of the distances between a point on a conic and a fixed point (the focus) and between the point and a fixed line (the directrix). For e = 0 a circle is produced, for 0<e<1 an ellipse is produced, for e = 1 a parabola is produced and for e>1 the conic produced is a hyperbola.
Conics of different eccentricities
http://www.math.odu.edu/cbii/calcanim/#defel Two animations of ellipses with different eccentricities.
A measure of the shape of an orbit, or how far it diverges from a circle. If e = 0, the orbit is a perfect circle. If e is less than 1 the orbit is an ellipse, and the nearer e is to 1, the more elongated the ellipse. If e = 1 exactly, the orbit is a parabola, and if e is greater than 1 the orbit is a hyperbola. The orbits of the planets and major satellites are ellipses of small eccentricity. Eccentricity is one of the elements of an orbit (see Elements, Orbital).
The extent to which an elliptical orbit departs from a circular one. It is usually expressed as a decimal fraction, regarding a circle as having an eccentricity of 0.
The orbits of the outer planets of the Solar System. The eccentricity of a circular orbit is zero. Pluto is the only planet with a large eccentricity.
Credit: NASA
- French East India Company
- French empire
- French Equatorial Africa
- French Foreign Legion
- French Indo-China
- French Indo-China War (1946–54)
- French, John Denton Pinkstone, 1st Earl of Ypres (1852–1925)
- French Revolution (1789)
- French Wars of Religion
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- Frenkel defect
- Frenkel–Kontorowa model
- freon
- frequency
- frequency analyser
- frequency analysis
- frequency and timing system
- frequency band
- frequency bridge
- frequency cap
- frequency changer
- frequency compensation
- frequency control
- frequency counter
- frequency-dependent negative resistor