[MtnClimber]

In this X-ray view of the entire sky, giant bubbles are clearly visible extending above and below the plane of the Milky Way galaxy. The bubbles likely come from the supermassive black hole at the galaxy’s center.

[Seruzawa]

Interesting. Naturally this explanation will be invalidated and replaced in a decade or two. There's only one way to solve it:

[NohSpinZone]

Double bubble, you say? That's one large piece of chewing gum.