A new study that was published earlier this month in the Astrophysical Journal offers an explanation for the origins of a peculiar and enigmatic feature located near the center of the Milky Way galaxy, known as the Fermi Bubbles.
The "bubbles" in question are a pair of massive orbs of gas, cosmic rays and dust that extend above and below the galactic plane for about 25,000 light-years on each side of it, and are only visible in "high-energy gamma-ray light", as Live Science points out.
And while the origins of these orbs remain unclear at this time, the study authors suggest that they are a product of what the media outlet describes as a "series of black hole belches" which began some 6 million years ago.
Using computer simulations, the scientists argue that the "bubbles" might've formed due to a massive shockwave which, in turn, might've occurred when two jets of ionized matter were emitted by Sagittarius A* - a supermassive black hole located at the center of the Milky Way.
"A forward shock is generated as soon as the jet punches through the ambient halo gas," the study postulates. "[After] 1 million years, the jet is switched off. ... After [5 million years], the bubble expands to its current size as observed."
The whole process would've lasted for about a million years, the scientists note, adding that their hypothesis might help explain the nature of certain other features of our galaxy's center.