Using new 21-cm radio observations made with NSF's Green Bank Telescope, astronomers have discovered over 250 neutral gaseous clouds being blasted out of the center of our Milky Way Galaxy into interstellar space.
These clouds are likely a product of the same phenomenon that created the Fermi Bubbles. It has been known for some time that energetic processes in the center of the Milky Way have created fast, hot winds expanding into intergalactic space with temperatures of millions of degrees and velocities of thousands of km per second. Most large galaxies have winds like this. The accidental discovery that some of this outflowing hot gas has entrained cold hydrogen clouds was made by the Australian ATCA telescope measuring the 21-cm radio emission emitted by interstellar hydrogen atoms. This implied that there could be an undiscovered population of clouds carrying matter out of the nucleus of the Milky Way. The hydrogen clouds are important on their own, but they also serve as probes of the hot wind. It is difficult to measure conditions within the very hot wind, but the cool clouds can trace it in the same way that on Earth, a handful of leaves tossed upwards can show the direction…