This relatively short cosmictime frame makes this event a very rare phenomenon.
这个相对来说比较短的宇宙时间范围内发生了罕见的现象。
2
In principle, one can trace that history back in cosmictime by observing a so-called standard candle, a class of astronomical object whose intrinsic luminosity is uniform.
原理上,我们可以通过观测所谓的标准烛光(一种天体,它的绝对光度是相同的)来追溯宇宙内的历史。
3
Another possibility is that the accelerated expansion arises not from a substance but from a modified form of gravity, one that behaves differently on cosmic scales of time and space.