Our Galactic Centre: “enormous energetic event”
Every time a scientist tells us we have nothing to fear, another will admit that they often don’t know much at all. Some 2012 theorists have suggested our galactic centre might be the cause of a 2012 event. For some, like me, it is because most galaxies have very energetic centres, and we haven’t been watching ours long enough to know if it is as benign as it appears. For others, it is a misunderstanding of the “galactic alignment” meme. Scientists have told us that we have no reason to fear our galactic centre, because the super-massive black hole that resides there (right where extensions of the tail of Scorpio and the arrow of Sagittarius cross) is quiet.
Well, new observations may cause scientists to rethink the risks:
Two huge bubbles that emit gamma rays have been found billowing from the center of the Milky Way galaxy, astronomers have announced.
The previously unseen structures, detected by NASA’s Fermi Gamma-ray Space Telescope, extend 25,000 light-years north and south from the galactic core.
“We think we know a lot about our own galaxy,” said Princeton University astrophysicist David Spergel, who was not involved in the discovery. But “what we see here are these enormous structures … [that] suggest the presence of an enormous energetic event in the center of our galaxy.”
…”Another hypothesis, which is perhaps even more dramatic, is that the [mostly dormant] black hole at the center of the galaxy is active for a little bit,” he said.
Scientists know that a supermassive black hole resides at the center of our galaxy, and it didn’t get so big by sitting quietly. Instead, the black hole must go through stages when it gobbles up massive amounts of material.
When galactic black holes are actively feeding, they tend to spew high-energy jets from their poles. Astronomers have found such active galactic nuclei elsewhere in the universe, but have never before seen any convincing proof of this process happening in the Milky Way.
“So [the gamma-ray bubbles] might be the first evidence for a major outburst from the black hole at the center of the galaxy,” Finkbeiner said.