Astronomers have always thought of the Milky Way as Andromeda’s little sister (our nearest galactic playmate), but new evidence suggests we’re about the same size. A good question to ask at this juncture would be, “How in God’s name do you measure the galaxy?”
It turns out you can use 27 radio telescopes in New Mexico to determine how quickly we’re spinning (600,000 miles per hour, according to the new results), and then figure out how much mass could generate that velocity. Too much math for me; I’d forget to carry a one somewhere.
So be proud. We’re no longer the runt of the Local Group.