Dyson Spheres, The Ultimate Alien Megastructures, Are Missing From The Galaxy
“When you draw an inference about distance based on the light you observe, and then make a measurement in a completely different fashion (via geometry), those two figures should line up. The fact that Gaia has seen a few misalignments could indicate a number of possibilities, and alien megastructures certainly are one of them. It’s only human nature for our minds to go straight towards the most fantastic explanation, especially when the discovery of our lifetime would await us down that path. But the most reasonable and mundane is that these interesting objects simply aren’t single stars, but have unseen binary companions: a very common occurrence in this Universe. The fact that there is no excess infrared radiation, a requirement of Dyson-type structures, points away from the alien megastructure hypothesis.”
Over the past few years, especially in the aftermath of the curiosity that is Tabby’s Star, people have been particularly curious about the possibilities of alien megastructures around distant stars. Here on Earth, we can harness only the solar energy that’s incident on our planet; there’s billions of times more that our Sun emits that we never access. But an advanced-enough civilization could do exactly that, and wouldn’t it be exciting if such a civilization existed within our galaxy? Well, the Gaia satellite just released the largest astronomical data set ever of stars within the galaxy, and there are a few objects that show an interesting signature: a mismatch of their inferred parallax distance with the distance you infer from their brightness. Could it be an almost-finished megastructure like a Dyson sphere?