How massive is the Milky way?
Many scientists have been working on figuring out the exact mass but as per the current measurement the Milky Way weighs in at around 700,000,000,000 solar masses, or in other words, the mass of our sun multiplied by 700 billion.
So how do we go about measuring a galaxy which is so so enormous?
First of all, galaxies not only include stars, planets, moons, gases, dust, and other objects and material, they also contain a good chunk of dark matter.
mc R OMI mim The method is based on the equations of gravity derived by Isaac Newton more than 300 years ago, which tell you that the speed and distance at which a smaller body rotates around a larger one is related to the mass of the larger object.
To measure the Milky Way's mass, Eadie is using the velocities of globular star clusters which are basically spherical collection of stars that orbit our galaxy.
To determine the total velocity of a ciuster, it has to be measured in two directions: . . one along our line-of-sight (a straight unobstructed view), and the other across the plane of the sky (perpendicular to the line of sight)