Yes. It would be immensely more difficult if we could not look back in time. There would be no microwave background, for example, so no knowledge of the fluctua

Yes. It would be immensely more difficult if we could not look back in time. There would be no microwave background, for example, so no knowledge of the fluctuations in density soon after the Big Bang. As a comparison, do you think it would be easier for an alien to figure out the life cycle of humans if they could see a few humans at every period of life (like in astronomy) or if they only saw middle-aged humans, but many more of them?