# epicycle

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## epicycle:

see Ptolemaic systemPtolemaic system
, historically the most influential of the geocentric cosmological theories, i.e., theories that placed the earth motionless at the center of the universe with all celestial bodies revolving around it (see cosmology).
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## epicycle

(ep -ă-sÿ-kăl) See Ptolemaic system.

## Epicycle

(religion, spiritualism, and occult)

When Earth was viewed as the stationary center of the universe, the retrograde motion of the planets was explained in terms of epicycles—smaller orbits that circled in the reverse direction from the planets’ usual motion.

## Epicycle

an auxiliary circle in Ptolemy’s geocentric system of the world.

Epicycles were introduced to explain the retrograde motions of the planets. It was presumed that a planet moves uniformly along the epicycle while its center E (see Figure 1) moves along another circle, called the deferent, with its center at the earth. Because a deferent with one epicycle could not explain many irregularities in the motions of the planets, systems of epicycles were introduced. It was believed that the center of the second epicycle moved along the first epicycle, while the center of the third epicycle

Figure 1

moved, in turn, along the second epicycle, and so on. The planet is located in the last epicycle.

## epicycle

[′ep·ə‚sī·kəl]
(mathematics)
The circle which generates an epicycloid or hypocycloid.
References in periodicals archive ?
A block diagram of possible power losses in the device for controlling speed changes by means of a differential transmission with a closed hydraulic system through an epicycle, where the driving link is the carrier, and the driven one is the epicycle, is shown in fig.
Namely, I proposed that the planets travel in epicycles, not perfect spheres as he originally maintained.
Next he finds observations that give a position for the object that differs from the mean motion; the point of greatest difference must equal the radius of the epicycle.
10] A Platonist may at this point either bite the bullet, and argue that musical works are indeed discovered,[11] or devise some ingenious epicycle that allows for the possibility that abstract entities are created.
By the time of the next Ellis, The Rules of Attraction (1987), instead of a puppy-novelist, we confronted an epicycle of the Ptolemaic system of hype, according to which the heavens move in eccentric orbits around a vacuous editorial need for gas.
Nevertheless, three forces are identified that impinge on Navajo land use: the shift in relations with colonial powers (Spain, and then the United States); contradictory relations between family-based production and community/tribal organization; and the epicycle of erosion.
Epicycle Business Solutions; Integrated Sysems Solutions; and Looks Creative Designing Arts, Inc.
A clear example is offered by D'Costa, who innovatively--and unpersuasively and irrelevantly to people outside his theological circle--has declined to resolve the problem of deceased "righteous" "non-Christians" by following Joseph DiNoia in opening up purgatory to non-Christians who die in a state of grace (itself an epicycle implausible to those outside this particular theological stance).
Now a senior fellow with the Council on Foreign Relations and the New America Foundation, Beinart has doubled-down with The Icarus Syndrome, tracing the roots of the Iraq mistake to a generation-skipping hubris that has produced an epicycle of disastrous foreign policy overreach.
193) There is always, it would seem, another epicycle at the ready.
Though often attacked, this paradigm has been particularly long-lived, in part because it was flexible enough--with the aid of an epicycle or two--to encompass even such novel structures as Stephen Greenblatt's Renaissance Self-Fashioning and its many avatars.
This epicycle was carried around the rim of the larger sphere in a great circle.

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