by Staff Writers Kingston, Canada (SPX) Jul 03, 2012 An
international team of astronomers have discovered evidence that
our Milky Way had an encounter with a small galaxy or massive
dark matter structure perhaps as recently as 100 million years
ago, and as a result of that encounter it is still ringing like
a bell. The discovery is based on observations of 300,000 nearby
Milky Way stars by the Sloan Digital Sky Survey (SDSS). Stars in
the disk of the Milky Way move up and down at a speed of about
20-30 kilometers per second while orbiting the center of the
galaxy at a brisk 220 kilometers per second. The positions and
motions of these nearby stars weren't quite as regular as
previously thought, according to the study results. "We clearly
observe unexpected differences in the Milky Way's stellar
distribution above and below the Galaxy's mid-plane having the
appearance of a vertical wave - something that nobody has seen
before," says Queen's University physicist Larry Widrow, lead
researcher on the project. The