Brad Kushner <<Brad>> sends:

http://www.upi.com/Science_News/2016/01/06/Astronomers-use-bow-waves-to-locate-stars-on-the-run/5771452095121/?spt=trc

Bow waves are waves that move out in front of an object moving
through gas or liquid.

They're named for the bow, or front, of a ship, which creates V-shaped waves
that propagate outward as the vessel moves through the water. Ducks swimming
across a pond make them, too. So do stars.

Recently, astronomers scanned the Milky Way looking for bow waves in an effort
to locate runaway stars. They found a lot.