WHY IS OUR GALAXY BLOWING BUBBLES?
For a decade astronomers have been looking to the sky and sighing with frustration as the Milky Way spews giant plumes of high-energy particles with no firm explanation as to what is behind them. They were first discovered in 2010 using NASA's Fermi Gamma-ray Space Telescope, but despite numerous studies over subsequent years these bubbles – which given current astronomical theory shouldn't exist at all – continue to be a mystery.
“What we see are two gamma-ray-emitting bubbles that extend 25,000 light years north and south of the galactic centre,” said Professor Douglas Finkbeiner, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, after recognising the celestial feature. Named Fermi Bubbles, they were seen to extend 50,000 light years in total above and below the plane of the galaxy.
The discovery was, colleague Meng Su would later admit in a roundtable discussion hosted by the Kavli Foundation, “quite a big shock”, even though evidence of other bubble-like structures exist in the universe. “Finding these bubbles in the Milky Way wasn't anticipated by any theories,” he continued. The reason? The supermassive black hole in the centre of the Milky Way is far less massive than in the galaxies where other bubbles were observed. A small
