And since there were pulsating Cepheid stars whose actual distances we already knew, this let us build a cosmic measuring stick.

既然我们已经知道这些有规律脉动的造父变星的实际距离，这就给我们造出一把宇宙测量尺。

" To scale" means that the actual distance on the map between two points – between, say, one city and another city – the distance on the map is the same in proportion to the actual distance.

“按比例”是指地图上两点之间的实际距离——比如一个城市和另一个城市之间——地图上的距离与实际距离成比例。