We live in the Milky Way galaxy - a disk-shaped collection of about 400 billion stars including the Sun. Many of those stars and much of the dense gas between the stars concentrate into large arms that spiral outward from the galactic center.
Astronomers have worked for decades to map the Milky Way and its spiral arms. They have just discovered a new spiral arm on the far side of the galactic center from Earth, which is a virtual twin of a known arm on the near side of the galactic center. The Milky Way therefore shows a beautiful symmetry, with two matching spiral arms lazily spinning near the galaxy's center.
Tom Dame of the Harvard-Smithsonian Center for Astrophysics (CfA) presented this finding today in a press conference at the 212th American Astronomical Society meeting.
"Our galaxy isn't as messy as many thought. What we have found is evidence of some balance and order, like the yin and yang of Chinese philosophy," said Dame.
clipped from: physorg.com 