- Why? - Tide.

-为什么 -汰渍
The washing powder.

洗衣粉
The fluorescence in the washing powder is caught by the UV light.

洗衣粉里的荧光物质在紫外线照射下发光
Why do you know that?

你怎么知道的
When stars are born and when they die, they emit UV radiation.

恒星诞生和毁灭时会辐射出紫外线
So, if we could see the night sky in ultraviolet light,

如果只能看到夜空里的紫外线
then almost all the stars would disappear

现在的星星就都不见了
and all that we would see are these spectacular births and deaths.

只剩下恒星壮丽的诞生和毁灭
- I reckon it would look a little... - Like that.

-我觉得应该... -就像这个
- So, why? - Why what?

-为什么 -什么为什么
Why Spanish medieval poetry?

为什么要研究中世纪西班牙诗歌
I suppose I like to time travel...

应该是我喜欢穿越时空吧...