The shape of the Milky Way galaxy, our solar system's home, may look a bit like a snail, but spiral galaxies haven't always had this structure, scientists say. In a recent report, a team of researchers said they now know when and how the majestic swirls of spiral galaxies emerged in the unicerse. Galaxies are categorized into three main types, based on their shapes: spiral, elliptical and irregular. Almost 70 percent of those closest to the Milky Way are spirals. But in the early universe, spiral galaxies didn't exist. A husband and wife team of astronomers, Debra Meloy Elmegreen at...