The scientists used some super complex math and stats calculations to arrive at that estimate. More specifically, the team employed a combination hierarchical Bayesian analysis along with direct measurements of the velocity of globular clusters. Astronomers can estimate the mass of the sun by observing its gravitational pull on the Earth. The same can be done for the Milky Way by measuring its gravitational pull on those globular clusters. This new estimate includes stars, planets, moons, dust, dark matter and more that make up the galaxy.

Researchers say the key to this calculation is that they include any uncertainties in the estimate. Gwendolyn M. Eadie, a doctoral candidate at McMaster University in Hamilton, Ontario, explained to The New York Times that the methods used here could have wider implications for future research. The methods have been employed in other fields before, but they're becoming more useful to astronomers now that computers have enough processing power to handle the complex calculations.