Milky Way flutters as it spins

Galaxy has added motion along its north-south axis

Observations suggest that the Milky Way galaxy (shown) flutters along its north-south axis.

NASA/JPL-Caltech/S. Stolovy

As the Milky Way spirals around a central, supermassive black hole, the galaxy may also flutter like a flag from top to bottom.

Astronomers led by Mary Williams of the Leibniz Institute for Astrophysics in Potsdam, Germany, tracked stars in the suburbs of the solar system and found that the stars sway in and out along the galaxy’s north-south axis. The team describes the motion in a paper accepted for publication in the Monthly Notices of the Royal Astronomical Society.

What’s causing the Milky Way’s flutter is unclear, but the astronomers suggest the motion could come from the movement of the galaxy’s spiral arms or from a collision with a smaller galaxy, both of which would influence scientists’ model of how the galaxy moves.

Ashley Yeager is the associate news editor at Science News. She has worked at The Scientist, the Simons Foundation, Duke University and the W.M. Keck Observatory, and was the web producer for Science News from 2013 to 2015. She has a bachelor’s degree in journalism from the University of Tennessee, Knoxville, and a master’s degree in science writing from MIT.

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