As an actual real world physicist and astronomer, I watch this thread with great interest, as it may be the "only" aliens actually discovered in my lifetime.
Be this as it may, it seems logical for the existence of a third probe, as you always need three of something to triangulate a position, or come from a direction. In my opinion, this may lead to "placing probes" in certain positions and directions, in orientation with particular planets, stars or other locations, to build or add to a map. We (you) are just finding things now and getting indications of their hidden purpose. Meta-Alloys fix stations corrupted by Ancient Artefacts, nav becons giving out numbers, morse code from objects, and other alignments where signals occur.
It all points to the need for someone to place objects in alignment with points in space, and accurately assessing the purpose of signals and directions. There is (or will be) a galactic map and some direction indicated which will emerge here.
I read two interesting threads, which had nothing to do with each other, but one "discovery" of an FDev mistake, which was supposed to give a FSD boost of 25%, actually gave a boost of 300%, and some pilot (congrats) was able to fly 8400lys above the plane of the milky way galaxy. The other thread, was the location of a system well outside our current ability to reach it (in the beginning of this thread on page #1). Now, with this "accidental" discovery, and the claim it opens up "new possibilities" in Elite and space travel, we may need to duplicate this event, while placing probes at certain locations, on the way out to this system.
I'm certainly speculating here, but in physics, you follow the points and pay attention to direction, and when applicable, note any actions and reactions along the way. In this way, we build a theory and a model (or here in Elite, a theory and a map) and then verify the results with tests and observations.
Frankly, this is the best logic puzzle I have seen in a game for quite some time. It is either being developed as we try to solve it, and we (you) surprised Sir David with an early discovery. Sir David has laid it all out, and now sits back and enjoys those brave enough and smart enough to solve his puzzle for the location of the aliens of his world.
Will there be a profound message for all mankind, or a warning not to cross this line?
So, put on your thinking caps and think outside the box.