Astronomers have observed, for the first time in three dimensions, that gas from spiral galaxies is blown upward and downward at high velocity, far out of the galaxy. The observations confirm the prevailing theory of galaxy evolution that says that star-forming galaxies drive intergalactic winds by venting their gas along the poles. The astronomers have published their findings in Nature.

“Until now, observations have been difficult to interpret, but thanks to this study we can no longer ignore bipolar winds.”