light year
noun [ C ] uk/ˈlaɪt ˌjɪər/ us/ˈlaɪt ˌjɪr/
光年（指光1年走过的距离，约为9.5兆公里）
the distance that light travels in one year (about 9.5 million million kilometres)
Idiom
light years awayidiom （时间上）极其遥远的
an extremely long time from now in the past or future
It all happened when I was at college, which seems light years away now that I'm over 50. 那都是发生在我上大学期间的事情，已经非常遥远了，我现在都已经50多岁了。