astronomical unit
1
6.5
- noun
- /ˌæstrəˈnɑːmɪkəl ˈjuːnɪt/
- Specialized
:
unidad astronómica
- Despite some uncertainty about the largest dimension, a Halley-size comet has a large interaction region, roughly 0.1 astronomical units or greater.
- astronomical units from the Sun
Examples
-
"Four astronomical units," Amanda replied, "give or take a fraction."
Fiction book (2001) -
Average distance from the Sun: 39.5 Astronomical Units.
Academic text (2004) -
So why should a planet be a planet at one astronomical unit from the sun?
-
The last column gives the least distance between the centers of the Earth and the Sun in astronomical units.
Blog text (30) -
Now we can do this where this is in astronomical units and this down here is in parsecs.
-
This is shown by the magnitude variation when the comet is closer to the Sun than six astronomical units.
Academic text (1992) -
Subject to change as circumstances warrant, the mother ship and escort will take an ecliptic orbit around the sun at approximately three-fourths of an astronomical unit.
Fiction book (2001) -
The computations were particularly difficult because the masses of Mercury and Venus had to be determined from their effects on the comet and because the comet sometimes passes within one astronomical unit of massive Jupiter.
Academic text (1991) -
Its perihelion distance (the distance of closest approach to the Sun) is 1.03 astronomical units, and its orbit is inclined 32 degrees to the plane of the ecliptic.
Academic text (1992) -
The distance from Earth to the Sun is defined as one astronomical unit.
Synonyms
1
7.4
A unit of distance equal to the average space between Earth and the Sun, about 150 million kilometres
A unit of length equal to the average distance from Earth to the Sun
Surface Forms
Morphology
The meaning is directly and compositionally derived from 'astronomical' (relating to astronomy/space) + 'unit' (a defined measure): a measurement used in astronomy, typically for distances. This is a transparent, cross-linguistically straightforward compound so a B1 learner who knows the constituents can grasp the MWE's general meaning (even if they may not know the exact numerical value).
Etymology
The term astronomical unit comes from using the distance between the Earth and the Sun as a simple measuring unit. Because astronomical refers to 'stars and planets', saying one astronomical unit is an easy way to talk about distances inside our solar system.