A new technique for estimating the mass of galaxies promises more reliable results, especially when applied to large datasets generated by current and future surveys, according to a research team led by Ekta Patel at the University of Arizona. Published in the Astrophysical Journal, the study is the first to combine the observed full three-dimensional motions of several of the Milky Way’s satellite galaxies with extensive computer simulations to obtain a high-accuracy estimate for the mass of our home galaxy.

Determining the mass of galaxies plays a crucial part in unraveling fundamental mysteries about the architecture of the universe. According to current cosmological models, a galaxy’s visible matter, such as stars, gas and dust, accounts for a mere 15 percent of its mass. The remaining 85 percent is believed to reside in dark matter, a mysterious component that never has been observed and whose physical properties remain largely unknown. The vast majority of a galaxy’s mass (mostly dark matter) is located in its halo, a vast, surrounding region containing few, if any, stars and whose shape is largely unknown.[…]

Source: How do you weigh a galaxy? Especially the one you’re in? – ScienceBlog.com