But when we look out to space, over astronomical distances, to the stars, planets and galaxies beyond, then light's finite speed has profound consequences.

但当我们仰望天空观察远在天文距离之外的恒星 、行星和星系时，光速就会产生重大的影响。

But here we come up against the most difficult of all obstacles to contact with people on other planets -- the astronomical distances which separate us.

然而，在和外星人联系中我们遇到的最大困难是分隔我们的天文距离。