One large Milky Way galaxy or many galaxies? 100 years ago, Edwin Hubble settled astronomy's 'Great Debate'
A hundred years ago, astronomer Edwin Hubble dramatically expanded the size of the known universe. At a meeting of the ...
ESA’s Gaia Spacecraft Wraps Up Revolutionary Milky Way Mapping Mission
ESA’s decade-long Milky Way Gaia mapping mission still has tons of data to release over the next few years. Expect surprises.