Typically such gas clouds are not able to travel the Milky Way.
A giant cloud of hydrogen approaches the Earth and the impact may be unavoidable, as confirmed by ABC newspaper in Spain. Known as “Smith‚Äôs Cloud,” an image of the capsule was captured by the Green Bank Telescope, the analysis was done by Robert. C. Byrd.
According to him, the secret of the survival of this “cloud” 9,800 light-years-longs, 3,300 wide-is a protective shell of dark matter that allowed him to pass through the different layers of the Milky Way. Maybe we need to call in Dr Who