Proper-motion
noun
1.
Astronomy. the angular motion of a star relative to a suitably defined frame of reference, expressed in seconds of arc per year.
proper motion
noun
1.
the very small continuous change in the direction of motion of a star relative to the sun. It is determined from its radial and tangential motion
proper motion
Movement of a celestial object in the sky that is the result of the object’s own motion in space rather than of how it is observed from Earth. All celestial objects are in motion with regard to each other, but because objects outside the solar system are so distant from Earth most of them seem fixed in the sky. Over long periods of time, however, their proper motions result in gradual changes in their relative positions as viewed from Earth. Measurements of these motions by modern instruments can be extrapolated forward or backward in time to produce a celestial sphere on which the stars have somewhat different positions than they have today. In general, objects nearest the Earth have the greatest proper motions and will move the farthest on the celestial sphere in such extrapolations. Extremely distant objects, although they may be moving through space at equal or higher speeds than nearby objects, will appear to move little in the sky even over thousands of years.
Read Also:
- Proper-name
noun 1. Grammar. a noun that is used to denote a particular person, place, or thing, as Lincoln, Sarah, Pittsburgh, and Carnegie Hall. noun 1. the name of a person, place, or object, as for example Iceland, Patrick, or Uranus Compare common noun related adjective onomastic
- Properness
adjective 1. adapted or appropriate to the purpose or circumstances; fit; suitable: the proper time to plant strawberries. 2. conforming to established standards of behavior or manners; correct or decorous: a very proper young man. 3. fitting; right: It was only proper to bring a gift. 4. strictly belonging or applicable: the proper place for […]
- Proper-noun
noun 1. Grammar. a noun that is used to denote a particular person, place, or thing, as Lincoln, Sarah, Pittsburgh, and Carnegie Hall. noun 1. the name of a person, place, or object, as for example Iceland, Patrick, or Uranus Compare common noun related adjective onomastic
- Proper palmar digital nerve
proper palmar digital nerve n. Any of ten palmar nerves of the digits of the hand derived from the common palmar digital nerves. Each nerve supplies a palmar quadrant of a digit and a part of the dorsal surface of the distal phalanx.
- Proper plantar digital nerve
proper plantar digital nerve n. Any of ten nerves derived from the common plantar digital nerves. Each nerve supplies a plantar quadrant of a toe and part of the dorsal surface of the distal phalanx.