special

Tag archives for special

Is Dark Energy the same as Acceleration?

In a comment on my last post, What is Dark Energy, Kendall asks the following, which is such a good one I think it deserves its own post: I thought the expansion was accelerating? Aren’t you saying that it is on its way down to 85% of its current rate? Sounds like expansion is slowing,…

Why doesn’t Light Age?

There’s a graduate student that I’m sort-of mentoring/working with at Arizona, named Xiaoying Xu (hi Xiao!). She’s bright and curious, and she asks some very good questions. She asked me one yesterday that’s pretty tough to wrap your head around: How do I explain to someone why light doesn’t age? Well, here on Earth, time…