Maybe It's a Dyson Sphere

Editor’s Note: This article previously appeared in a different format as part of The Atlantic’s Notes section, retired in 2021.

That’s what many readers are suggesting in response to Ross’s captivating piece on a mysterious star that many scientists suspect might harbor an alien civilization in its orbit. The basics:

A Dyson sphere is a hypothetical megastructure that completely encompasses a star and hence captures most or all of its power output. It was first described by Olaf Stapledon in his science fiction novel, Star Maker. The concept was later popularly adopted by Freeman Dyson. Dyson speculated that such structures would be the logical consequence of the long-term survival and escalating energy needs of a technological civilization, and proposed that searching for evidence of the existence of such structures might lead to the detection of advanced intelligent extraterrestrial life. Different types of Dyson spheres correlate with information on the Kardashev scale.

Many readers cast their skeptical eyes, expertise, and general nerdom:

Actual “spheres” are science fiction simplifications. Dyson’s proposal is better described as a “Dyson Swarm” —i.e. a vast amount of small objects all co-orbiting the star, managed to stay out of each other’s way, and maximizing the amount of solar energy that can be collected from the star.

Another reader points to science fiction series:

In Iain Banks’ Culture novels, lots of people live in Orbitals—big spinning rings orbiting a star. The people in that high tech civilization could build planets at will, but they consider it wasteful since they just live on the surface. But custom-made environments where you can walk around in shirtsleeves are highly valued. Sort of like how they make artificial islands in the Persian Gulf shaped like fish.

Another reader points to Ringworld, by Larry Niven, seen below. This reader also stays within the realm of sci-fi:

If it were a literal Dyson’s Sphere, then the star’s light would be blocked entirely, or constantly. If it were a Dyson “swarm,” the objects collecting solar energy would likely be too small and too few in number to obfuscate the star’s light in a manner detectable 1480 light years away. Also, Dyson’s “swarm” would cause the star to blink in a recognizable pattern due to the uniform spacing of each satellite in orbit.

My guess is that one of the simpler explanations will turn out to be true (that is, if the answer ever becomes known): a massive asteroid field, a “sea of comets” as the Boyajian paper proposes, or something along the lines of a natural phenomena. To make some connection between a flickering star to cosmic-level signs of extraterrestrial life feels like an overly optimistic and unrealistic leap. But then again, I’ve been wrong before, even if it was only once.

Another reader also looks to alternatives:

A civilization capable of building megastructures visible from 1500 light years away may well have found alternate energy sources to solar output (mining the void, etc.) I like the Dyson sphere (or swarm) analogy because it means that something like this might actually be visible to us—but in reality I doubt that solar mining is going to remain the most efficient means of energy production that far into a civilization’s technological development.

Another tries to relate:

We have lots of wind farms around here in California, and many of them have old windmills just sitting there motionless, rusting. Not worth fixing them or taking them down. The newer ones are twice as high and whirring away. Perhaps a partial Dyson Sphere could indicate something similar, and they have moved on to other things.

Also, is it not possible that as a civilization deploys a Sphere, the supply of energy increases, the cost of material for the sphere increases, and the willingness to invest in more Sphere drops? A partial Dyson Sphere might offer the best cost-benefit outcome. I mean, I have 44 solar panels on my roofs. I could have installed more, but the more I install, the worse an investment it is to me.

Also, is it not possible that a civilization just doesn’t need any more energy? For me, with my 44 panels, perhaps in a decade, I’ll have more efficient equipment, and my energy needs drop as technology gets better, instead of growing. I’m not “a civilization” so the analogy is weak, but isn't it possible that a world reached “peak energy demand”?

A direct reply from another reader:

I think Dyson was really thinking along your lines; the civilization builds one orbital solar array and it works, so they build another, and another, and another as needed. After awhile, you also start running out of real estate, and the same thing happens with orbital habitats. Eventually there are so many that it starts to dim the star. From Dyson:

A solid shell or ring surrounding a star is mechanically impossible. The form of “biosphere” which I envisaged consists of a loose collection or swarm of objects traveling on independent orbits around the star. The size and shape of the individual objects would be chosen to suit the inhabitants. I did not indulge in speculations concerning the constructional details of the biosphere, since the expected emission of infrared radiation is independent of such details.

If you have anything to add on Dyson Spheres, want to offer more theories, or just want to nerd out about the star in general, drop me an email and I’ll post. Until then, try to wrap your head around this: