| 单词 |
protogalaxy |
| 释义 |
ˈprotogalaxy Astr.
Also with hyphen.
[f. proto- + galaxy n.]
A vast mass of gas, not yet formed into stars, postulated as a preliminary stage in the evolution of a galaxy.
1959Astrophysical Jrnl. CXXX. 43 These nuclei had already originated before the protogalaxy condensed into stars. 1969Monthly Notices R. Astron. Soc. CXLV. 417 The central part of the cloud begins to collapse, and the collapsing region gradually grows until it eventually includes almost the entire mass of the proto-galaxy. 1977Sci. Amer. Oct. 43/3 Shapley's work laid the foundation for the present view that the globular clusters were formed 10 to 13 billion years ago during the gravitational collapse of the protogalaxy, a vast cloud of gas consisting of hydrogen and helium.
Hence protogaˈlactic a., of, pertaining to, or being a protogalaxy.
1969Monthly Notices R. Astron. Soc. CXLV. 407 We assume for simplicity that the proto-galactic material consists of pure hydrogen. 1977Sci. Amer. Oct. 44/2 As the protogalactic cloud contracted local regions of higher density became self-gravitating and condensed within a relatively short time into globular star clusters. |
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