Astronomers have used an intense burst of radio waves originating from a nearby galaxy to inspect the halo of gas cocooning our own Milky Way galaxy. The scientists studied the way that the light of the so-called fast radio burst, or FRB, was dispersed as it traveled from deep space and into our galaxy as a means to estimate how much matter resides in the galaxy's halo. This is a bit like shining a flashlight through fog to see how thick the cloud is; the more matter there is, the more the light will disperse.