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Astronomical Unit (a.u.) of Length

The astronomical unit (a.u.) is a unit of length used primarily in astronomy to describe distances within our solar system. It is defined as the average distance between the Earth and the Sun.

Key facts:

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  1 astronomical unit ≈ 149,597,870.7 kilometers (about 93 million miles)

  
  
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  Used to measure distances between planets and other objects in the solar system

  
  
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  Provides a convenient scale for expressing space distances that are too large for kilometers but too small for light-years

  
  

The astronomical unit helps astronomers communicate and calculate orbits, planetary positions, and space missions with clarity and precision.