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GRE阅读高频题目:Supernova-智课教育旗下智课教育
智 课 网 G R E 备 考 资 料
GRE阅读高频题目:Supernova-智课教育旗下智课教
育
Supernova D 89-12
Astronomers observe a supernova that is dimmer than
expected because of dust screening,If a supernova (the
explosion of a massive star) triggered star formation from dense
clouds of gas and dust, and if the most massive star to be
formed from the cloud evolved into a supernova and triggered a
new round of star formation, and so on, then a chain of
star-forming regions would result. If many such chains were
created in a differentially rotating galaxy, the distribution of stars
would resemble the observed distribute in a spiral galaxy.
This line of reasoning underlies an exciting new theory of
spiral-galaxy structure. A computer simulation based on this
theory has reproduced the appearance of many spiral galaxies
without assuming an underlying density wave, the hallmark of
the most widely accepted theory of the large-scale structure of
spiral galaxies. That theory maintains that a density wave of spiral
form sweeps through the central plane of a galaxy, compressing
clouds of gas and dust, which collapse into stars that form a
spiral pattern.
相关文章:
If a supernova (the explosion of a massive star) triggered star
formation from dense clouds of gas and dust, and if the most
massive star to be formed from the cloud evolved into a
supernova and triggered a new round of star formation, and so
on, then a chain of star-forming regions would result. If many
such chains were created in a differentially rotating galaxy, the
distribution of stars would resemble the observed distribution in
a spiral galaxy (spiral galaxy: n.(=spiral nebula)螺旋星云,旋涡星云).
This line of reasoning underlies an exciting new theory of
spiral-galaxy structure. A computer simulation based on this
theory has reproduced the appearance of many spiral galaxies
without assuming an underlying density wave, the hallmark (a
distinguishing characteristic, trait, or feature “the dramatic
flourishes which are the hallmark of the trial lawyer Marion K.
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