How is cosmology similar to archaeology?
The deeper you look the further back in time you see.
Since the speed of light is finite, the greater the distance you look, the further back in time you are seeing.
With archaeology, the deeper you dig, the further back in time you are looking.
In both disciplines you find clues and piece them together into consistent stories.
In both disciplines it is difficult to conduct experiments: The things you are interested in have already happened. You can try some limited things out over shorter timeframes, but it's more about observation and plausible explanations.