Jun 27, 2013 11:47 AM EDT
Spiral Galaxies More Massive Than Previously Thought: Halo of Gas Surrounds Milky Way
Spiral galaxies, like our own Milky Way, form spectacular pinwheels of stars, planets and debris in space. Now, it turns out that these galaxies may be a lot more massive than previously believes. Scientists have discovered that halos of gas can extend outward for over one million light-years.