Huge Bubbles Found at the Heart of Our Galaxy

Scientists have detected two gigantic bubbles of high-energy radiation spilling out from the Milky Way's center that may have erupted from a supermassive black hole.  The mysterious structures each span 25,000 light-years across, and are emitting gamma rays, the highest-energy wavelength of light. The bulbous features may be evidence of a burst of star formations a few million years ago, researchers said. Or they may have been produced when a supermassive black hole in the center of our galaxy gobbled up a bunch of gas and dust.

The newly discovered structures remain an enigma for now, scientists said. "We don't fully understand their nature or origin," said study leader Doug Finkbeiner of the Harvard-Smithsonian Center for Astrophysics.

Finkbeiner and his team used observations from NASA's Fermi Gamma-ray Space Telescope, which maps the sky's gamma-ray light. The scientists processed data from Fermi's Large Area Telescope, the highest-resolution gamma-ray detector ever launched.

By filtering out the fog of background gamma rays suffusing the sky, the researchers were able to pick out the huge bubbles. The scientists weren't flying blind; previous studies by other astronomers using other instruments had found intriguing clues that a huge, previously unknown structure might be lurking near the Milky Way's heart.
"We were definitely looking for something," Finkbeiner told reporters . "Some hints of this signal had been seen before, but not convincingly."
"The two bubbles are dramatic, enigmatic and huge. They're emitting about the same amount of energy as 100,000 exploding stars, or supernovae," Finkbeiner said.

The structures extend as far as the distance between our solar system and the galaxy's core (the bubbles don't envelop Earth; they spread out in a different plane). Researchers aren't yet sure what created the bubbles. But the structures appear to have sharp, well-defined edges, suggesting they were formed by a large, rapid and relatively recent release of energy. Two leading candidate causes, according to Finkbeiner, are a surge of star formations several million years ago and a burst of activity by the Milky Way's central black hole, which is as massive as four million suns.

Astronomers have observed powerful jets blasting from the supermassive black holes in other galaxies. These jets are fueled by matter falling into the black hole. "These monsters, once fed, can produce very powerful explosions," said David Spergel, chair of Princeton University's astrophysics department.  While there is no evidence the Milky Way's black hole has such jets today, it may have in the past, researchers said.

Figuring out what drives these bubbles may help us to figure out what drives the universe. It seems almost every week now there are amazing discoveries in space. We are getting close to the secret of our origins. I have to admit I still have a problem comprehending why there is something instead of nothing.