NASA | STScI | HubbleSite | 2015 Jan 05
At a time when our earliest human ancestors had recently mastered walking upright, the heart of our Milky Way galaxy underwent a titanic eruption, driving gases and other material outward at 2 million miles per hour.[c]Quasar's Light Yields Clues to Outflow
Credit: NASA, ESA, and A. Field (STScI)[/c]
Now, at least 2 million years later, astronomers are witnessing the aftermath of the explosion: billowing clouds of gas towering about 30,000 light-years above and below the plane of our galaxy.
The enormous structure was discovered five years ago as a gamma-ray glow on the sky in the direction of the galactic center. The balloon-like features have since been observed in X-rays and radio waves. But astronomers needed NASA's Hubble Space Telescope to measure for the first time the velocity and composition of the mystery lobes. They now seek to calculate the mass of the material being blown out of our galaxy, which could lead them to determine the outburst's cause from several competing scenarios.
Astronomers have proposed two possible origins for the bipolar lobes: a firestorm of star birth at the Milky Way's center or the eruption of its supermassive black hole. Although astronomers have seen gaseous winds, composed of streams of charged particles, emanating from the cores of other galaxies, they are getting a unique, close-up view of our galaxy's own fireworks. ...
Probing the Fermi Bubbles in Ultraviolet Absorption: A Spectroscopic Signature
of the Milky Way's Biconical Nuclear Outflow - Andrew J. Fox et al
- arXiv.org > astro-ph > arXiv:1412.1480 > 03 Dec 2014 (v1), 19 Dec 2014 (v2)
http://asterisk.apod.com/viewtopic.php?t=30857