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News Release Archive:

News Release 71 of 1039

January 5, 2015 05:15 PM (EST)

News Release Number: STScI-2015-03

Hubble Discovers that Milky Way Core Drives Wind at 2 Million Miles Per Hour

An American Astronomical Society Meeting Release

January 5, 2015: 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. 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, dubbed the Fermi Bubbles, 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. The graphic shows how Hubble probed the light from a distant quasar to analyze the outflow. The quasar's light passed through one of the bubbles. Imprinted on that light is information about the outflow's speed, composition, and eventually mass.

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Illustration Credit: NASA, ESA, and A. Feild (STScI)

Science Credit: NASA, ESA, and A. Fox (STScI)