- nebula:  As its form suggests, nebula was originally a Latin word, but it goes back to a prehistoric Indo-European base (*nebh- ‘cloud’) which produced a wide range of other descendants, including German nebel ‘cloud’, Greek néphos ‘cloud’, and Latvian debess ‘sky’. It also got into Old English, as nifol ‘dark’. The Latin word was originally used in English for a sort of ‘cataract’ over the eye, and the presentday astronomical application to a ‘cloud’ of stars did not emerge until the early 18th century. The derivative nebulous  is an earlier borrowing.
- nebula (n.)
- early 15c., nebule "a cloud, mist," from Latin nebula "mist, vapor, fog, smoke, exhalation," figuratively "darkness, obscurity," from PIE *nebh- "cloud" (cognates: Sanskrit nabhas- "vapor, cloud, mists, fog, sky;" Greek nephele, nephos "cloud;" German Nebel "fog;" Old English nifol "dark, gloomy;" Welsh niwl "cloud, fog;" Slavic nebo).
Re-borrowed from Latin 1660s in sense of "cataracts in the eye;" astronomical meaning "cloud-like patch in the night sky" first recorded c. 1730. As early as Hershel (1802) astronomers realized that some nebulae were star clusters, but certain distinction of relatively nearby cosmic gas clouds from distant galaxies was not made until 1920s, using the new 100-inch Mt. Wilson telescope.
- 1. The size of the nebula at this stage is inversely proportional to its mass.
- 2. The Trifid Nebula itself represents the final phase of star formation.
- 3. A powerful telescope can resolve a nebula into stars.
- 4. We have identified the Crab Nebula as the debris of this explosion.
- 5. A nebula is really a discrete mass of innumerous stars.
[ nebula 造句 ]