Spoiler alert: the Universe is expanding, and it's this redshift that allowed us to figure that out.

宇宙正在膨胀，正是这种红转移让我们得以发现这一事实。

That's just what galaxy redshifts are telling us.

这就是星系红移告诉我们的。

Today you learned that distant galaxies show a redshift in their spectra, which means they're moving away from us.

今天你知道了遥远的星系在它们的光谱中显示出红移，这意味着它们正在远离我们。

Remember, redshift stretches the wavelength of light.

记住，红移延伸了光的波长。

Then those can be compared to the supernovae redshifts, which is a different way of getting their distance.

然后可以将之与超新星的红移相比较，这是一种不同的距离测量方法。

It was as if the predictions based on the redshifts were underestimating the distances to the exploding stars.

似乎基于红移的预测低估了到爆炸恒星的距离。

Out away from earth you drift, This is known from your redshift.

你远离地球漂流， 这是从你的红移中得知的。

When light loses energy its wavelength gets longer — that's what cosmological redshift is.

当光失去能量，它的波长会变长，这就是宇宙学的红移。

And this trend of distant galaxies moving away from us, and from one another, is called cosmological redshift.

这种遥远星系 远离我们、彼此远离的趋势被称为 宇宙学红移。

Using the idea of lookback time, they could predict how far away it would be from us, and therefore calculate its redshift.

利用回溯时间的概念，他们可以预测它离我们有多远，从而计算它的红移。