Apparent Motion

Apparent motion may refer to:

In astronomy:

  • Apparent retrograde motion, the appearance that objects in the night sky move against the typical direction of motion
  • Improper motion, any effect which appears to cause the position of a celestial object to move
    • Aberration of light, improper motion due to the finite speed of light and the motion of Earth in its orbit around the Sun
    • Diurnal motion, improper motion due to the Earth's rotation on its axis
    • Parallax, improper motion caused by the Earth's orbit around the sun

In perceptual illusions:

  • Beta movement, an illusion of movement where two or more still images are combined by the brain into surmised motion
  • Illusory motion, the appearance of movement in a static image
  • Phi phenomenon, an illusion of movement created when two or more adjacent lights blink on and off in succession
  • Stroboscopic effect, a phenomenon that occurs when continuous motion is represented by a series of short or instantaneous samples
    • Wagon-wheel effect, temporal aliasing effect in which a spoked wheel appears to rotate differently from its true rotation
  • The illusion of movement deliberately sought by certain forms of op art (optical art)

Other uses:

  • Optical flow, a term used in computer science for the apparent motion of objects in a scene caused by the relative motion between an observer and the scene
  • The motion of objects observed from a non-inertial reference frame

Famous quotes containing the words apparent and/or motion:

    “Charity is a cop-out so traditionally female in its apparent self-effacement that there seems resonant comfort in it. We’re no longer supposed to serve the imaginations of men who have dominated us. We are to give up ourselves instead to those whose suffering is greater than our own. Looking down is just as distorting as looking up and as dangerous in perpetuating hierarchies.”
    —Jane Rule (b. 1931)

    “Wine gives a man nothing. It neither gives him knowledge nor wit; it only animates a man, and enables him to bring out what a dread of the company has repressed. It only puts in motion what had been locked up in frost.”
    —Samuel Johnson (1709–1784)