How much does our galaxy really weigh? Measuring the mass of a galaxy or of any other cosmic object of this type is quite complicated, since, if we focus on a galaxy, they not only contain cosmic dust, gases, stars, planets or moons, but also include other materials and a portion of invisible dark matter that has not been able to be detected directly – yet – in the laboratory but that can be deduced thanks to the gravitational effect on objects that are visible.
Thus, knowing the mass of the Milky Way is a difficult project. Up to now. A researcher from McMaster University (Canada), Gwendolyn Eadie, has proposed a precise answer to this challenge of astrophysics: 7×1011 solar masses; that is, the mass of our Sun multiplied by 700,000 million or 330,000 times the mass of the Earth.
To determine this figure, Eadie studied the mass of the Milky Way using the velocities and positions of globular star clusters that orbit our galaxy, whose orbits are determined by its gravity. He devised a system to use partially known speeds, in addition to the speeds that are absolutely known, to estimate the mass of the Milky Way.
The development of this new astronomical measurement method has been featured in The Astrophysical Journal and at the Astronomical Society of Canada conference in Winnipeg.
