We could guide stars into a graphstellation—a constellation that is also a form of writing.
The fleet assembles to adjust the trajectories of some of the larger Kuiper belt objects, cometlike bodies at the periphery of the solar system. (Moving those around won’t cause problems for inner planets like Earth.) Over a long period, the reconfigured Kuiper belt objects serve as a larger gravitational tractor to tilt the plane of the solar system and then to change the trajectory of the sun through the Milky Way. Meanwhile, we also will have sent clusters of spacecraft to 15 or so nearby stars. It could take many tens of thousands of years for the spacecraft to reach these stars and a much longer time to change their trajectories.
Why move stars around? Because then they could be guided into orbital formations that almost certainly would not have occurred naturally. An imaginable set-up period of tens of thousands of years could therefore be leveraged into a much longer period—billions of years, perhaps—during which aliens could observe the fruits of our efforts. A group of stars organized to present a sign in this way might be called a “graphstellation” (like a constellation, but also a form of writing).
To state the obvious, there are enormous challenges to doing this. The idea of a gravitational hedge fund is entirely speculative for now and might not be workable. Even if it can be done, our solar system is a poor candidate for manipulation. The mass of the entire Kuiper belt is perhaps one one-millionth the mass of the sun, so there isn’t much to work with. The coming decades will see a survey of the structures of nearby solar systems, however. Perhaps some nearby systems are better arranged for gravitational hedge fund action. An ideal solar system would have suitable gradations of adjacent orbital masses. Failing that, perhaps some other method of nudging a star’s path will come along.
The playfulness, open-mindedness, and intellectual generosity of the best scientists always amaze me, never more so than when I called Piet Hut at the Institute for Advanced Study to talk about the prospects for graphstellations. (He has, among many other things, been at the forefront of the study of strange but possible orbital structures.) The fact that we haven’t proved we can move asteroids, much less stars, doesn’t faze Piet at all. If the motivation for creating a graphstellation is valid and there is no proof that the idea is impossible, his view is that it is worth contemplating.
Piet immediately suggested a design for a multiply nested binary star graphstellation that would have the delightful technical designation “hyper-super-duper double-star system”: a pair of a pair of a pair of double stars, 16 total. This configuration would be stable and unlikely to interact with nearby stars. It also would do no harm to the solar system or life on Earth, should we end up as part of the formation. The set-up phase would coax pairs of stars into headings destined to bring them into mutual embrace in such a way that the pairings would eventually pair as well, and so on. Such a structure would be vanishingly unlikely to come about naturally, and it would be recognizable at a great distance. An alien observer wouldn’t have to be able to discern all the individual stars in order to notice that something funny was going on; the alien would only have to note subtle changes in the qualities of the light, wobbles in the position, and other clues.
Piet and I had an interesting exchange comparing graphstellations to the Egyptian pyramids. Is there something inherently macho about rearranging the stars, in the way the pyramids seem macho to us, or is it more like a lonely cry in the wilderness?
An interesting comparison can be made to the Dyson Sphere. In 1960 physicist Freeman Dyson suggested that an advanced civilization might want to capture all the solar energy from a star, and so might build a spherical structure all around it. He suggested looking around to see if there are any such spheres out there. None have been found thus far. A graphstellation would have far less utilitarian value to its creators, but it also would probably be far easier to build and detect than a Dyson Sphere.
The obvious next step is to look around and see if anyone out there has already created a graphstellation. This will not be a trivial exercise. There are a lot of stars, and we have to consider the potential range of graphstellation designs, not only the ones that have already occurred to us. But I am in the process of engaging my astronomer friends in the hunt. I have also been talking to people who plan space missions. Crazier things have happened.
