Science / Medicine : Milky Way May Have Taken 3 Times Longer to Form

Our Milky Way galaxy may have taken far longer to settle into its current shape than previously thought, according to a study published last week in Nature. For the past several decades, the standard view among astronomers was that a massive, spherical cloud of gas rapidly collapsed over a period no longer than 1 billion years to form the Milky Way’s orderly spiral of stars. But that scenario has been called into question in recent years, and new research bolsters claims that the galaxy formation process took at least three times longer, or 3 billion years.

A detailed chemical analysis of two globular clusters, associations of a few million stars thought to be the oldest objects in our galaxy, indicate that the clusters differ in age by about 3 billion years--one dating back about 13 billion years and the other about 16 billion years. That means researchers will have to develop a new theory about how the galaxy was formed.

The study was based on observations made by the Anglo-Australian Telescope in Siding Spring in Australia. Although the analysis looked only at two globular clusters in the Milky Way, the findings could have implications for all galaxies in the universe, according to Roger Bell of the University of Maryland.