annual parallax
Definition
- Noun:
- Astronomical measurement: The apparent shift in the position of a celestial object (like a star) when observed from two different points in Earth's orbit around the Sun, specifically from opposite sides of the orbit. This shift is used to calculate the object's distance.
Usage
- Scientific Context: Used exclusively in astronomy to describe a method for measuring stellar distances.
- The annual parallax of the star was measured to determine its distance from Earth.
- Astronomers use annual parallax to calculate the distances to nearby stars.
Advanced Usage
- As a baseline for the parsec: The measurement of annual parallax is fundamental to defining the astronomical unit of distance known as the parsec. One parsec is the distance at which an object would have an annual parallax of one arcsecond.
- A star with an annual parallax of 0.1 arcseconds is 10 parsecs away.
Variants and Related Words
- Heliocentric parallax: Another term for annual parallax, emphasizing the use of the Sun as a reference point.
- Stellar parallax: A general term for the parallax of stars, which is often (but not exclusively) measured as annual parallax.
- Parallax (noun): The general phenomenon of an object's apparent displacement due to a change in the observer's position. Annual parallax is a specific type of parallax.
Synonyms
- Heliocentric parallax: (Direct synonym)
- Trigonometric stellar parallax: (Descriptive synonym emphasizing the geometric calculation method)
Related Concepts (Not Phrasal Verbs or Idioms)
- Parsec: A unit of astronomical distance derived from annual parallax.
- Baseline: In annual parallax, the baseline is the diameter of Earth's orbit.
- Arcsecond: The unit (1/3600 of a degree) used to measure the tiny angle of annual parallax.
Noun
-
the parallax of a celestial body using two points in the earth's orbit around the sun as the baseline
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