Think you know what the Milky Way looks like? Think again.
Even if you know what 'everyone knows' the Sun is made of, how many moons Saturn has, where the magnetic north pole is, whether faster than light speeds have been demonstrated in the lab, and how may planets in the Solar System have rings, you may not know about the huge twin gamma ray bubbles at the center of the Galaxy.
NASA's Fermi Gamma-ray Space Telescope has unveiled a previously unseen structure centered in the Milky Way. The feature spans 50,000 light-years and may be the remnant of an eruption from a supersized black hole at the center of our galaxy."What we see are two gamma-ray-emitting bubbles that extend 25,000 light-years north and south of the galactic center," said Doug Finkbeiner, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., who first recognized the feature. "We don't fully understand their nature or origin.
These are HUGE - they take up half the night sky. Oh, and share nicknames with another new phenomena -- a chocolate bar (just do a search for 'galaxy bubbles'). Possibly caused by the bar magnet at the center, spinning... or is it a bowl of magnetic spaghetti? The Discover Blog posits "another possibility: The supermassive black hole at the center of the galaxy. While relatively quiet now, a furious period of gobbling up matter and blasting out jets of material in the past could have" produced the bubbles.
From Finkbeiner's paper:
We argue that these Galactic gamma-ray bubbles were most likely created by some large episode of energy injection in the Galactic center, such as past accretion events onto the central massive black hole, or a nuclear starburst in the last ~10 Myr. Dark matter annihilation/decay seems unlikely to generate all the features of the bubbles and the associated signals in WMAP and ROSAT; the bubbles must be understood in order to use measurements of the diffuse gamma-ray emission in the inner Galaxy as a probe of dark matter.
Or, my friend Lisa thinks, to use them as a time portal. 25,000 light years on either side of the Galactic plane, like two vast eyeballs looking at each other, like the headdress of an Egyptian God reflected, like a seed pod from the God tree, like.... a hydrogen atom.