An Etymological Dictionary of Astronomy and Astrophysics

The mixture of gases of which the earth’s atmosphere is composed. It is chiefly made up of Nitrogen (about 78%) and Oxygen (about 20%).

Etymology (EN): Air, from O.Fr. air, L. aer, Gk. aer, related to Gk. aura “breath, vapor;” PIE *wer- “to raise, lift.”

Etymology (PE): Havâ, from Ar., probably a loanword from Mid.Pers. vây “weather,” Av. vayah-, vaya- “weather, atmosphere,” from va- “to blow.” Cf. Skt. va-, Gk. aemi- “to blow;”
Av. vâta- “wind,” Skt. vata-,
L. ventus, Mod. Pers. bâd “wind.” PIE *we- “to blow”.

The mixture of gases of which the earth’s atmosphere is composed. It is chiefly made up of Nitrogen (about 78%) and Oxygen (about 20%).

Etymology (EN): Air, from O.Fr. air, L. aer, Gk. aer, related to Gk. aura “breath, vapor;” PIE *wer- “to raise, lift.”

Etymology (PE): Havâ, from Ar., probably a loanword from Mid.Pers. vây “weather,” Av. vayah-, vaya- “weather, atmosphere,” from va- “to blow.” Cf. Skt. va-, Gk. aemi- “to blow;”
Av. vâta- “wind,” Skt. vata-,
L. ventus, Mod. Pers. bâd “wind.” PIE *we- “to blow”.

Same as → cosmic-ray shower.

See also: → air; → shower.

Same as → cosmic-ray shower.

See also: → air; → shower.

A machine capable of flying by means of → buoyancy or → aerodynamic forces, such as an airplane, helicopter, glider, or balloon.

See also: → air; → craft.

A machine capable of flying by means of → buoyancy or → aerodynamic forces, such as an airplane, helicopter, glider, or balloon.

See also: → air; → craft.

The faint ever-present glow in the → night time → sky caused by the → collision
of → atoms and → molecules in Earth’s → upper atmosphere with high energy → particles and → radiation,
mainly from the → Sun. The airglow, also called nightglow, varies with time of night, → latitude, and → season.

See also: → air; → glow;
→ night.

The faint ever-present glow in the → night time → sky caused by the → collision
of → atoms and → molecules in Earth’s → upper atmosphere with high energy → particles and → radiation,
mainly from the → Sun. The airglow, also called nightglow, varies with time of night, → latitude, and → season.

See also: → air; → glow;
→ night.

A measure of the path length traversed by starlight through Earth’s atmosphere before it reaches the detector; it is taken relative to the length at the zenith.

See also: → air; → mass.

A measure of the path length traversed by starlight through Earth’s atmosphere before it reaches the detector; it is taken relative to the length at the zenith.

See also: → air; → mass.

The bright disk-like image of a point source of light, such as a star, as seen in an optical system with a circular → aperture.

Etymology (EN): Named after Sir George Biddell Airy (1801-1892), Astronomer Royal, great administrator, who much improved the equipment at Greenwich Observatory. → disk.

Etymology (PE): Gerdé, → disk; Airy, see above.

The bright disk-like image of a point source of light, such as a star, as seen in an optical system with a circular → aperture.

Etymology (EN): Named after Sir George Biddell Airy (1801-1892), Astronomer Royal, great administrator, who much improved the equipment at Greenwich Observatory. → disk.

Etymology (PE): Gerdé, → disk; Airy, see above.

A → transit circle that defines the position of the → Greenwich Meridian since the first observation was taken with it in 1851. Airy’s transit circle lies at longitude 0°, by definition, and latitude 51° 28’ 38’’ N.

See also: Named after Sir George Biddell Airy (1801-1892), Astronomer Royal, at the Royal Observatory in Greenwich from 1835 to 1881. Airy transformed the observatory, installing some of the most advanced astronomical apparatus of his day and expanded both staff numbers and their workload; → transit; → circle.

A → transit circle that defines the position of the → Greenwich Meridian since the first observation was taken with it in 1851. Airy’s transit circle lies at longitude 0°, by definition, and latitude 51° 28’ 38’’ N.

See also: Named after Sir George Biddell Airy (1801-1892), Astronomer Royal, at the Royal Observatory in Greenwich from 1835 to 1881. Airy transformed the observatory, installing some of the most advanced astronomical apparatus of his day and expanded both staff numbers and their workload; → transit; → circle.