A Galactic-scale gas wave in the solar neighbourhood.

For the past 150 years, the prevailing view of the local interstellar medium has been based on a peculiarity known as the Gould Belt, an expanding ring of young stars, gas and dust, tilted about 20 degrees to the Galactic plane. However, the physical relationship between local gas clouds has remained unknown because the accuracy in distance measurements to such clouds is of the same order as, or larger than, their sizes. With the advent of large photometric surveys and the astrometric survey, this situation has changed.