A Dyson sphere is a hypothetical megastructure that encompasses a star and captures a large percentage of its power output. The concept is a thought experiment that attempts to imagine how a spacefaring civilization would meet its energy requirements once those requirements exceed what can be generated from the home planet’s resources alone. Because only a tiny fraction of a star’s energy emissions reaches the surface of any orbiting planet, building structures encircling a star would enable a civilization to harvest far more energy.
Is dark matter just Dyson sphered stars?
While the idea is charming, a Dyson sphere itself would still consist of matter and as such it would emit radiation according to its temperature (https://en.m.wikipedia.org/wiki/Thermal_radiation). And since it surrounds a star it is heated from the inside and would definitely emit radiation that can be detected. Dark Matter is missing this radiation part and is only observed by its gravitation.
So the answer is no, unfortunately.
Edit to add disclaimer: this is shitpost level math here guys, I’m just spitballing.
It would definitely emit thermal radiation. if it was 99% efficient and the size of pluto’s orbit, around a star like the sun, and the energy was used to create matter, I think it would radiate the remaining energy as 0.009 W/m2 with a peak emission wavelength of 150micrometers. The James Webb telescope has infrared capabilities that max out at 28.5 micrometers so def not detectable.
But probably a dyson sphere would be smaller than pluto’s orbit, which would greatly increase the apparent power, and shorten the wavelength. idk it’s all imaginary.
I won’t subject you to my hand writing but I did (power of sun × 0.01)/(surface area of sphere with Pluto’s orbital radius) to get radiation intensity (0.009 W/m2). Then rearranged Stefan-Boltzmann law to solve for temperature (19.8K). Then used Wien’s Displacement Law to calculate the peak wavelength (1.5×10-4 m).
Maybe I’ll run the numbers again with a martian orbit radius, and 50% efficiency.
Okay I did the same calculation but with Martian orbit as dyson sphere size, and 50% efficiency I got a wavelength of 3.4um so nicely in the infrared range of JWST.
I think the sphere would need to be like 99.95% efficient to be undetectable by JWST at Martian orbit radius.
My initial reaction: “What? No.”
After thinking a little bit: “hmm I guess you could say that…”
Like I’m sure it’s not but I don’t know if it’s a worse explanation than any of the other ideas being considered. But I don’t know enough to even know how wrong I am.