How is it that we can be sure that it was Venus or Mars as the source of the observations? The reason for the question is that I'm considering the possibility that the observations were quite real, and that the events might have had a dramatic impact (figuratively and literally) on human life at the time, but that the comets/meteroids might have been other than the known planets. In other words, people observe a comet, perhaps that becomes an impacter (e.g., the Younger Dryas event), but successive generations look for the object in the sky and can't find it, but they do find Venus, Mars, and Saturn. So the story said that something moving in the night sky (like planets) developed streamers. Then the story becomes that the visible planets at one time had streamers.