Frozen Time
The past is regarded as definite, as unchangeable. Exactly for that reason it is principally knowable, and so, in a wider sense, knowledge.
We make it become actual knowledge in detecting and collecting remnants of past events, traces allowing us to reconstruct those events, to get a picture of what did happen.
All that happens leaves some traces. It is reflected somewhere. It changes something.
Knowledge is a kind of frozen activity. Solidified, definite, past.