星系退行 meaning in English

recession of galaxies

Continuing the above example , the galaxy is moving at a speed of about 9000km s away from us , given the speed of light is 3x10
把数值代入，便可以得出以上例子的星系退行速度为每秒九千公里。
American astronomer edwin hubble in 1929 discovered that the recession rate of galaxies was directly proportional to their distance . this is what we call the hubble s law which defines that v h
美国天文学家哈勃于1929年发现星系退行速度与其距离存在著正比的关系，即所谓哈勃定律：退行速度v h