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cluster – n. a group of things or people that are close together
light-year(s) – n. a unit of distance equal to the distance that light travels in one year, about 9.46 trillion kilometers
galaxies – n. the very large groups of stars that make up the universe
journal – n. a magazine that reports on things of special interest to a particular group of people
author(s) – n. a person who has written something
in one fell swoop – idm. done all at once or all together
obvious – adj. easy to see or notice
flash in the pan – idm. a brief, intense effort that produces no really major result
mature – adj. grown to full size
evolve(d) – v. to change or develop slowly often into a better, more complex, or more advanced state
