Source: www.nytimes.com
USA, November 8, 2010: There was something hiding in plain sight inside our own galaxy. A group of scientists working with data from NASA’s Fermi Gamma-Ray Space Telescope said Tuesday that they had discovered two bubbles of energy erupting from the center of the Milky Way. They are not exactly small, either, extending 25,000 light years up and down from each side of the galaxy and contain the energy equivalent to 100,000 supernova explosions.
“Wow,” said David Spergel, an astrophysicist at Princeton. “And we think we know a lot about our own galaxy,” Dr. Spergel added, noting that the bubbles were almost as big as the galaxy itself and yet unsuspected until now.
Jon Morse, head of astrophysics at NASA headquarters, said, “This shows again that the universe is full of surprises.”
The source of the bubbles is a mystery. One possibility is that they are fueled by a wave of star births and deaths at the center of the galaxy. Another option is a gigantic belch from the black hole known to reside at the center of the Milky Way. What it is apparently not is dark matter, the mysterious something that astronomers say makes up a quarter of the universe and holds galaxies together.