How are today's field galaxies different than distant ones?

we cant see them since they are delayed by light years

Explanation:

The reason why galaxies appear so different between our local universe and the distant one is because we are observing galaxies at different stages of their evolution as we look out in space. Telescopes are time machines, albeit ones that run only in reverse, and so the farther out we look with them, the progressively younger universe we see. Furthermore, we do not observe the universe from any special vantage point. So if we make the reasonable assumption that the physical laws we measure in the local cosmos are universal, we can conclude that the galaxies we observe in the early universe are analogous to the predecessors of the local galaxies. Thus, the differences we see between the different populations of galaxies provide direct insights into the nature of galaxy evolutio