I'd be interested in the radar images. When Pan Am 103 went down, the radar operators noticed the single radar return changed into multiple reflections that spread out over an approx. 11 mile area. That was the airborne debris they were picking up, consistent with a midair explosion.
It's hard to believe they don't know where this plane went. It was fairly close to land and should have been on radar.
First of all...there is a LOT that we simply do not know.
What we do "know" is not necessarily really known. For instance, we know that there is no debris field. Yet. It is entirely possible that we will find one tomorrow. Or the next day. It's been a long time but I don't think they found debris from that Air France crash for several days and they pretty much knew where it went down. In this case (one of the things we don't know) is where the plane went down. It could have gone down along its planned flight path or it could have gone down somewhere else...perhaps a hundred miles or more along some other vector.
We know that there were people aboard the plane who were traveling under names that were not their own. But what we don't know (yet) is whether or not they might have had terrorist-type (muslim) leanings.
We do actually know that there was zero indication of a problem prior to the plane's disappearance. We also know (or at least I think we do) that this particular plane had a transponder which sent its flight data (altitude, speed, direction of flight) out a couple of times a second. However, it is my understanding that the transponder had a limited transmission distance...something like 150 to 200 miles depending on altitude. This is (and again, according to my understanding) the reason that the plane vanished from the internet tracking sites when they did...because it had exceeded the distance that the transponder could transmit to the nearest (land based) receiver.
I have heard (unconfirmed) that spy satellites saw nothing as regards the flight. I have no expert knowledge of any kind regarding that type of technology so that, for me, is a big huge unknown.
I am going to say that maybe we will "know" a bit more in another day or two. Or not. Because that's an unknown, too.