天文距离

但是据NPR新闻的乔·帕尔卡报道，谈及天文距离时，“接近”是一个相对的说法。

But as NPR 's Joe Palca reports close is a relative term when it comes to astronomical distance .

分隔我们的天文距离。

The astronomical distances which separate us .

为了度量天文距离，人们把光在一年中走过的距离当作一个距离单位。

To measure astronomic distances one takes as a unit that distance which light travels in a year .

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。

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 .

天文单位距离的光行时

Light-time for astronomical unit distance

然后这边的木星到太阳有5个天文单位左右的距离，之后土星到太阳的距离大概有10个天文单位。

Then Jupiter 's right there at 5-point something , and then Saturn is about 10 astronomical units from the Sun .

所以为了研究它们的起源，科学家们使用了天文望远镜观测到距离很远的星系，他们必须要追忆一下过往的岁月。

So to study stellar origins , scientists use telescopes that allow them to see galaxies that are so far away , they 're essentially looking back in time .