New study claims Milky Way weighs half of Andromeda Galaxy

A new study has revealed the method for measuring the mass of galaxies accurately, according to which Milky Way has half the mass of its neighbor Andromeda Galaxy.

In this new study, researchers has culled previously published data that contained information about the distances between the Milky Way, Andromeda and other close-by galaxies, including those that weren't satellites, that reside in and right outside an area referred to as the Local Group.

For the first time, researchers were able to combine the available information about gravity and expansion to complete precise calculations of the masses of both the Milky Way and Andromeda.

Matthew Walker, an assistant professor of physics at Carnegie Mellon said that historically, estimations of the Milky Way's mass had been all over the map, but by studying two massive galaxies that were close to each other and the galaxies that surround them, they could take what they knew about gravity and pair that with what they knew about expansion to get an accurate account of the mass contained in each galaxy.

The researchers could calculate the mass of both the ordinary, visible matter and the invisible dark matter throughout both galaxies based on each galaxy's present location within the Local Group, after Walker was able to pinpoint the group's center by studying both the galaxies in and immediately outside the Local Group.

This study is published in the journal Monthly Notices of the Royal Astronomical Society.