There are strong differences between observing things in the recent past, and ongoing, in a continual process, the scientific process, and simply looking at something from long ago that you were not there to see in the process. The two are two different types of sciences. They're not the same in a variety of ways. That should be the emphasis. Of course, everything is in the past. But that is not the difference between the two sciences. The difference is that one is past-tense while the other is past-tense continuous. The second one is ongoing in the moment as the experiments and observations are taken place in real-time.