Our Galaxy and its Huge Mysterious Bubbles

Researchers have managed to create a data-based "portrait" of our galaxy blowing two of the largest bubbles ever seen. The bubbles, consisting largely of gamma rays, stretch for tens of thousands of light-years above and below the Milky Way Galaxy.

Douglas Finkbeiner first discovered the towering bubbles nearly four years ago, and since then, mounting evidence has continued to prove their existence. Strangely, despite being able to craft a relatively clear picture of their size and shape, researchers still have no idea what is causing them.

The latest project to craft a detailed portrait of these bubbles was co-led by Anna Franckowiak of the Kavli Institute for Particle Astrophysics and Cosmology.

Franckowiak, working with Dmitry Malyshev, found that the bubbles have very clear and measurable outlines - unlike the hazy "bubble" of a star's influence prior to interstellar space. The bubbles appear to be fixed at each pole of the Milky Way, billowing into two 30,000-light-year-tall spheres.

Interestingly, the Fermi's main instrument, the Large Area Telescope, has detected with near-certainty that gamma rays are reaching out that far, and yet there is no source of the rays. According to basic astrophysical knowledge, they shouldn't be there.

Yet, there they are; two massive enigmas whose only proof existence is that advanced instruments can "see" them.

"Since the Fermi bubbles have no known counterparts in other wavelengths in areas high above the galactic plane, all we have to go on for clues are the gamma rays themselves," Frankowiak said in a recent release.

According to the researchers, it was "very tricky" to take near-perfect measurements of the bubbles, as there are plenty of explainable gamma rays within the Milky Way that can interfere with the Fermi's readings.

However, "subtracting all those contributions didn't subtract the bubbles," Franckowiak said. "The bubbles do exist and their properties are robust."

The researchers plan to continue to gather data on the bubbles, all the while wracking their brains in trying to explain how they are there.

Their latest work has been accepted for publication in The Astrophysical Journal, and should be treated as preliminary research until official release.