This is cool:
We’re putting the far side of the galaxy on the map. The most precise measurement yet of an object on the far side of the galaxy’s centre is paving the way for a definitive map of the other side of the Milky Way.
It’s difficult to observe anything on that side of the galaxy because of the dense, frenetic swarm of dust and gas at its centre. Thomas Dame at the Harvard-Smithsonian Center for Astrophysics in Massachusetts and his colleagues got around this by looking at a jet of radio waves that can outshine any emissions coming from that mess of stars.
“It’s a very bright source, indicative of a flamboyant region of star formation, and these regions are almost always located in the spiral arms of the galaxy,” says Dame. He and his team pinned down the source’s location to the Scutum-Centaurus arm of the galaxy, probably one of the Milky Way’s two major arms.
To do this, they used parallax measurements, which take into account differences in measurements from two points in space. […]
“The idea that you could be doing this for more objects on the far side of the galaxy is really exciting,” says Robert Benjamin at the University of Wisconsin, Whitewater. “How can you talk about the structure of our galaxy when you only have half of it?”
Dame says with this technique we could have an accurate and complete map of the entire Milky Way within 10 years.