for National Geographic News
Published November 10, 2010
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," Princeton University astrophysicist David Spergel, who was not involved in the discovery, said during a press briefing Tuesday. But "what we see here are these enormous structures … [that] suggest the presence of an enormous energetic event in the center of our galaxy."