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Dreyer, Johan Ludwig Emil

(Encyclopedia)Dreyer, Johan Ludwig Emil yōˈhän lo͝otˈvĭkh āˈmēl [key], 1852–1926, Danish astronomer, b. Copenhagen, who worked in Great Britain. He was assistant astronomer at the earl of Rosse's observa...

Atkins, Anna

(Encyclopedia)Atkins, Anna, 1799–1871, English photographer and botanist who specialized in images of botanical specimens. The daughter of scientist John George Children, she married John Pelly Atkins in 1825. Sh...

Uranus , in astronomy

(Encyclopedia)Uranus yo͝orāˈnəs, yo͝orˈə– [key], in astronomy, 7th planet from the sun, at a mean distance of 1.78 billion mi (2.87 billion km), with an orbit lying between those of Saturn and Neptune; its...

radiometer

(Encyclopedia)radiometer rāˌdēŏmˈətər [key], instrument for detection or measurement of electromagnetic radiation; the term is applied in particular to devices used to measure infrared radiation. One of the ...

Magellanic Clouds

(Encyclopedia)Magellanic Clouds măjˌəlănˈĭk [key], two dwarf galaxies located in the far southern sky and visible to the unaided eye; they are classified as irregular because they show no definite symmetry or...

nebula

(Encyclopedia)nebula nĕbˈyo͝olə [key] [Lat.,=mist], in astronomy, observed manifestation of a collection of highly rarefied gas and dust in interstellar space. Prior to the 1960s this term was also applied to b...

Hazlitt, William

(Encyclopedia)Hazlitt, William, 1778–1830, English essayist. The son of a reform-mindeed Unitarian minister, he abandoned the idea of entering the clergy and took up painting, philosophy, and later journalism. He...

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...

MacEwen, Sir William

(Encyclopedia)MacEwen, Sir William məkyo͞oˈən [key], 1848–1924, Scottish surgeon. A professor of surgery at the Univ. of Glasgow, he was noted for his work on bone grafting, on the radical cure of hernia, and...

Mackenzie, Sir William

(Encyclopedia)Mackenzie, Sir William, 1849–1923, Canadian railroad builder and financier, b. Ontario. In the early 1870s he became a railroad contractor. He constructed portions of the Canadian National and the C...