Milky Way Weighs As Much As 700 Billion Suns, New Study Reveals

First Posted: Jun 02, 2016 09:27 AM EDT

A new study reportedly suggests that the weight of the Milky Way is equal to the mass of 700 billion suns. Furthermore, there is more dark matter present in our galaxy than previously estimated, and it is believed to be present in a cloud around the Milky Way.

Researchers from Canada's McMaster University in Ontario calculated the probable weight of the Milky Way, which includes all types of visible matter like stars, planets, moons, dust, dwarf galaxies orbiting our galaxy as well as dark matter surrounding it, with a new modeling method. The latest findings about the Milky Way's weight can help cosmologists get a better understanding about our galaxy's past and future, according to scientists.

"Understanding our galaxy's mass puts it into a better cosmological context," said Gwendolyn Eadie, study leader from McMaster. "People who study the evolution of galaxies look at how the mass relates to its evolution. If we have a better handle on what the mass of the Milky Way is, we can understand how it and other galaxies form and evolve". Incidentally, the rates at which stars form, exist and die are linked to the overall mass of their galaxy.

Eadie designed a process to calculate the Milky Way's dark matter through the use of the known velocities and motions of 89 globular clusters (ancient groups of stars) that surround our galaxy, and which are easier to track than an individual star because they are well defined, relatively large and located at different distances throughout the galaxy. Furthermore dark matter has a predictable effect on them, in terms of pull and push, because the clusters orbit the galactic center. Eadie took the newly estimated mass of dark matter and added the known masses of visible objects in the Milky Way to create a mass profile of our galaxy, which gave a total estimate of the mass contained within any distance from the galactic middle.

The researcher's final estimate compared the mass of the Milky Way to 700 billion suns, and since our galaxy's stellar mass is currently thought to be around 60 billion suns, and one to three more percent is taken up by gas and dust, the new mass estimated by Eadie suggests that dark matter takes up as much as 88 percent of the Milky way's mass.

Eadie's work is not the first that tried to calculate the mass of the Milky Way; however it is one of the most in depth analyses that incorporates a wide range of data sources, as per scientist Alan McConnachie. Earlier studies about Milky Way's mass individually generated numerous estimates, ranging from 100 billion to 1 trillion suns.

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