I'm not sure how much this adds to our knowledge of Stonehenge, but some pits have been found recently to the northwest and northeast of the structure:http://cosmiclog.msnbc.msn.com/_news/2011/11/28/9074269-pits-add-to-stonehenge-mysterySeems to me that this simply confirms our knowledge about the astronomical underpinnings of the site, since the pits are in line with the heelstone (by which the course of the rising and setting sun took on the Summer Solstice). It is also cool about the researcher's theory that they may have lit fires in the pits, so that the rising sun would have appeared to come out of fire on the ground.
Do we really have any knowledge about Stonehenge beyond suppositions that it served some possible astronomical or religious purpose? It is difficult to know anything when the only thing we have about the motivation or intent of it's builders are guesses and the ravings of modern “Druids”.
Obviously, being a prehistoric site, our knowledge about it is limited, but I think it is pretty clear that it had an astronomical purpose. It is also known that it was not actually a Druid structure, even though modern-day “Druids” try to lay a claim on it.
But do we actually “know” anything about the site other than it's location ad the origin of the stones used to construct it? I don't think so, the vast majority of what we think we knw is in fact supposition that has gained so much currency it has become accepted as fact.
Well, I think that we can certainly know certain things about it, even if some other things remain unknown. The post-and-lintel system, the types of joints, the fact that the stones were brought in from elsewhere, and the ability of some civilization to construct even simple vertical elements with such heavy stones which weigh in the tons – these indicate a level of sophistication among the builders. The fact that stones lines up right along the trajectory of the sun on the summer solstice indicate that it had some astronomical significance, even if we do not know the exact nature of its function. By dating the structure, we can also tell when it was built from around 2500-1600 B.C., which is a long time, meaning it was added onto over time. And since the Druids came around after it was built, we can't say it was a Druid-designed structure (I am not sure the extent to which the Druids may have used it after the fact).There is probably much more that archaeology has informed us about the structure. Beyond these facts, there is naturally going to be some supposition to "fill in the holes", but so long as they're reasonable conclusions I don't have a problem with them.