A unit of length equal to the average distance between the earth and the sun ( about 92,955,807.27 miles ).
Abbreviation: Astronomical unit
- E.E. Barnard - (1857-1923) American observational astronomer best known for his discovery of Barnard's Star. The red dwarf star, with a proper motion of 10.3 arc seconds per year, has the highest proper motion relative to the sun of any known star.
- Catalogue of 349 Dark Objects in the Sky - A catalog of dark nebula compiled by American astronomer E.E. Barnard and published in 1927.
There is no formal definition for a bolide but a generally accepted one is a bright meteor that explodes. There are several accepted brightness criteria with a wide range of magnitudes: -4 (Venus) to -14 (Full Moon).