A vast river of neutral hydrogen bridges two galaxies that are beginning to enter the monstrous Virgo Cluster, and this structure is helping astronomers better understand our Milky Way's relationship with the nearby Magellanic Clouds.
The two galaxies, named NGC 4532 and DDO 137, are in fact falling into the Virgo Cluster at 547 miles (880 kilometers) per second, and in doing so are plowing through a vast cloud of gas that surrounds the cluster. For the galaxies, this is like wading through hot treacle that scours their leading edges, heating and tearing out hydrogen gas that then forms a 1.6-million-light-year-long tail.
