But these enormous gamma-ray emitting lobes aren't immediately visible in the Fermi all-sky map. However, by processing the data, a group of scientists was able to bring these unexpected structures into sharp relief.
Each lobe is 25,000 light-years tall and the whole structure may be only a few million years old. Within the bubbles, extremely energetic electrons are interacting with lower-energy light to create gamma rays, but right now, no one knows the source of these electrons.
Are the bubbles remnants of a massive burst of star formation? Leftovers from an eruption by the supermassive black hole at our galaxy's center? Or or did these forces work in tandem to produce them? Scientists aren't sure yet, but the more they learn about this amazing structure, the better we'll understand the Milky Way.
For an animation that shows the inverse Compton scattering responsible for the gamma rays, go to #10690.
For an animation that shows an artist's interpretation of the Milky Way galaxy and the lobes, go to#10691.