蜀之唐人
在無意義的世界中活出有意義的生活
正文
Last night, I was reading "The Universe in a Nutshell" about redshift of distant galaxies -- they are leaving us at higher speed if they are farther away from us.
If a galaxy is, say 1 million light-years, away from earth, its light takes 1 million years to reach us. All we see NOW is what happened to the galaxy 1 MILLION YEARS AGO. Thus, our conclusion should be that this galaxy is moving away from us at higher speed 1 million years ago.
Similar thought, the closer galaxies, which we see their more recent events, moves away from us at a lower speed.
Does this mean that the universe's expansion is slowing down?
If a galaxy is, say 1 million light-years, away from earth, its light takes 1 million years to reach us. All we see NOW is what happened to the galaxy 1 MILLION YEARS AGO. Thus, our conclusion should be that this galaxy is moving away from us at higher speed 1 million years ago.
Similar thought, the closer galaxies, which we see their more recent events, moves away from us at a lower speed.
Does this mean that the universe's expansion is slowing down?
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