Stellar Caravan

The sun traveled across the Milky Way alongside thousands of stars

- Jacek Krywko

OUR SUN WAS BORN 4.6 BILLION YEARS AGO near the crowded center of the Milky Way and then migrated roughly 10,000 light-years outward to the peaceful galactic suburbs it currently occupies. Now a pair of recent studies in Astronomy and Astrophysics argues that the sun did not make this trip alone.

Details of the sun’s journey can be found in its chemical composition, says Tokyo Metropolitan University astronomer Daisuke Taniguchi, a coauthor on both studies. “Astronomers know that the sun’s birthplace lies closer to the galactic core than its current position,” Taniguchi explains. The Milky Way’s dense inner regions formed stars faster and accumulated heavy metals far more quickly than the outer edges—and a star with the sun’s age and chemical components would not have been able to form at its present location. But getting there required crossing a dramatic border.