And alpha is something that we can measure at distant places in the universe and thereby back in time by looking at these atomic spectral lines.
我们可以在宇宙里遥远的地方测量阿尔法常数,从而通过研究这些原子光谱线回到过去。
2
Physicists have no trouble using, on the one hand, picoseconds (trillionths of a second) or even femtoseconds (quadrillionths of a second) to discuss timeat the atomic scale.