nebula

英 ['nebjʊlə] 美['nɛbjələ]

复数: nebulas; nebulae;

nebula 星云

来自拉丁语nebula,云，雾，蒸气，来自PIE*nebh,云，词源同Neptune.

nebula: nebula: [17] 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 [16] 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.: 这个阶段星云的大小与其质量成反比。

2. The Trifid Nebula itself represents the final phase of star formation.: 三叶星云本身代表着恒星形成的最后阶段.

3. A powerful telescope can resolve a nebula into stars.: 一架高性能的望远镜能从星云中分辨出星球来.

4. We have identified the Crab Nebula as the debris of this explosion.: 我们已证明蟹状星云就是这次爆炸的遗迹.

5. A nebula is really a discrete mass of innumerous stars.: 一团星云实际上是无数星体不连续的集合体.