In the distant Hewaixingji, as photons arrive at our planet a points during enables light waves to reach our red shift, Hubble's law called the Hubble redshift. However , expansion of the universe makes very long to comply time, this observation with the red shift, is the decreasing density of the uni verse, the Hubble constant has also been decreasing, that the Hubble constant is dynamic. In the spec trum of cosmic scale redshift, the Hubble redshift is the Hubble constant by dynamic conducted%在遥远的河外星系，由于光子到达地球需要很长的时间，这其间使得到达地球观测点的光波发生红移，该红移遵从哈勃定律，所以被称为哈勃红移．然而宇宙的膨胀使得宇宙的密度逐渐下降，哈勃常数也在不断的减小，即哈勃常数是动态变化的．在研究宇宙尺度下的光谱红移时，哈勃红移是按动态的哈勃常数进行的．
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