Yes, it's unlikely and pretty tin-foil-hat, but wouldn't it be nuts if it turned out to be a manufactured black hole? http://accelerating.org/articles/transcens

Yes, it's unlikely and pretty tin-foil-hat, but wouldn't it be nuts if it turned out to be a manufactured black hole? http://accelerating.org/articles/transcensionhypothesis.html http://accelerating.org/articles/transcensionhypothesis.html Intelligences could be expected to slowly accrete the mass of their parent star, rather than lifting or collapsing that mass and then inefficiently recreating fusion within the black hole (if the laws of physics even allow the latter, which they may not). In other words, you might absorb your star in a passive and gravitationally-driven process that would look a lot like a low mass X-ray binary (LMXRB) system to external observers, but in which the black hole companion begins as a planet mass black hole on the order of 1000 times less massive than the star companion, which should be a main-sequence star, likely with a spectral class G, like our Sun. Approximately 100 LMXRBs have been discovered in our galaxy to date, and about 13 of these have been found in the globular clusters, areas at the rim of our galaxy that may not harbor intelligence. They have also been found in many distant galaxies, again often in globular clusters. Few have involved G class stars, and none have yet been discovered with the very high, 1,000:1 mass ratio the hypothesis appears to predict. This may simply be a problem of detection. XRBs emit X-rays only when they are "eating" their companion sun, a transient phenomenon. Chandra, our best X-ray observatory, may also not have the sensitivity or persistence needed to detect very high mass ratio LMXRBs, or those that absorb their star's matter very infrequently or in very small doses. More research and theory is needed in this area.