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Varadkar, Leo Eric

(Encyclopedia)Varadkar, Leo Eric, 1979–, Irish politician, b. Dublin, grad. Trinity College Dublin (2003). The son of an Irish nurse and an Indian doctor, he practiced as a junior doctor before qualifying as a ge...

corona, in astronomy

(Encyclopedia)corona, luminous envelope surrounding the sun, outside the chromosphere. Its density is less than one billionth that of the earth's atmosphere. The corona is visible only at the time of totality durin...

infrared astronomy

(Encyclopedia)infrared astronomy, study of celestial objects by means of the infrared radiation they emit, in the wavelength range from about 1 micrometer to about 1 millimeter. All objects, from trees and building...

gamma-ray astronomy

(Encyclopedia)gamma-ray astronomy, study of astronomical objects by analysis of the most energetic electromagnetic radiation they emit. Gamma rays are shorter in wavelength and hence more energetic than X rays (see...

ultraviolet astronomy

(Encyclopedia)ultraviolet astronomy, study of celestial objects by means of the ultraviolet radiation they emit, in the wavelength range from about 90 to about 350 nanometers. Ultraviolet (UV) line spectrum measure...

neutrino astronomy

(Encyclopedia)neutrino astronomy, study of stars by means of their emission of neutrinos, fundamental particles that result from nuclear reactions and are emitted by stars along with light. Approximately 100 billio...

X-ray astronomy

(Encyclopedia)X-ray astronomy, study of celestial objects by means of the X rays they emit, in the wavelength range from 0.01 to 10 nanometers. X-ray astronomy dates to 1949 with the discovery that the sun emits X ...

Stratospheric Observatory for Infrared Astronomy

(Encyclopedia)Stratospheric Observatory for Infrared Astronomy: see infrared astronomy. ...

Nuffield Radio Astronomy Laboratories

(Encyclopedia)Nuffield Radio Astronomy Laboratories: see Jodrell Bank Observatory. ...

Bolt, Usain St. Leo

(Encyclopedia)Bolt, Usain St. Leo, 1986–, Jamaican sprinter. Unusually tall (6 ft 5 in./1.96 m) for his sport, he won the gold medal for the 200-m sprint at the 2002 world junior championships and then broke the ...