Source: Smithsonian Astrophysical Observatory (SAO)
Milky Way's new arm. Credit: T. Dame.
Our Milky Way galaxy, like other spiral galaxies, has a disk with sweeping arms of stars, gas, and dust that curve around the galaxy like the arms of a huge pinwheel. The Sun, Earth, and solar system are located in a spur of material that lies between two of the spiral arms, collectively orbiting around the galaxy about 25,000 light-years from its center.
Using a small 1.2-meter radio telescope on the roof of their science building in Cambridge, CfA astronomers Tom Dame and Pat Thaddeus used carbon monoxide emission to search for evidence of spiral arms in the most distant parts of the galaxy, and discovered a large new spiral arm peppered with dense concentrations of molecular gas. (read source)






