>>12949191OP's pic is not a supervoid, it's a gas cloud called Barnard 68, and it's actually relatively small, only about twice the mass of our sun. Also, infrared light passes right through it.
Voids are on a much larger scale, they aren't objects but literal regions in the entire universe. And they are far from being empty "holes" standing out in the universe. There is plenty of matter in them, except it's relatively low on density compared to the rest of the universe. That's literally all there's to it
