Astronomers in New York have revised the size estimate for our galaxy . They now say it is 150,000 light - years wide , not 100,000 light - years . This is based on photo - imagining a ring of galaxies called the Monoceros Ring . Previously this was thought to belong to a nearby dwarf galaxy . Now astronomers are fairly certain it is part of the Milky Way .
Astronomers in New York have revised the size estimate for our galaxy . They now say it is 150,000 light-years wide , not 100,000 light-years . This is based on re-examining a ring of stars called the Monoceros Ring . Previously this was thought to belong to a nearby dwarf galaxy . Now astronomers are fairly certain it is part of the Milky Way .