Light travels at 186,000 miles per second, so one light-year is nearly 6 trillion miles.
ANALYSIS: Welcome to the Milky Way Transit Authority
Astronomers are eager for a higher-resolution, three-dimensional views of the Monoceros Ring, and another ring even farther out, from Europe's Gaia telescope.
Meanwhile, they are interested in seeing if ripples found in gases in the Milky Way are related to what has been observed in the stars.
"In the gas, we have seen a couple of perturbations, these vertical oscillations, in the outer part of the galaxy," astronomer Leo Blitz, with the University of California, Berkeley, told Discovery News.
As far as signs of an intruder galaxy, one may have already been found, he added. Publication of that discovery is pending.
The research by Newberg and colleagues will be published this week in the Astrophysical Journal.