Fermi bubbles

Bubbles above and below the Milky Way galaxy. Illustration: Fermi Telescope on NASA's website

“Impossible” Cold Clouds Inside Fermi Bubbles Located Above and Below the Milky Way

Discovery of dense clouds of neutral hydrogen at the center of vast structures challenges hypothesis about age and stability of Fermi bubbles
Edge: Fermi Bubbles - Artist's impression of giant Fermi bubbles emerging from the core of the Milky Way Galaxy. Image: NASA

Mysterious objects at the edge of the electromagnetic spectrum