A Huge Hydrogen Halo Envelops The Milky Way

Gazing on 732,225 galaxies with the 2.5-meter telescope of the Sloan Digital Sky Survey has revealed the veil of diffuse hydrogen gas enshrouding the Milky Way. After combining this staggering number of spectra — recorded patterns of wavelengths revealing clues about the nature of a cosmic target — astronomers Huanian Zhang and Dennis Zaritsky report the first detections of diffuse hydrogen wafting about in a vast halo surrounding the Milky Way. [Read More]