As large as our Milky Way is, scientists have discovered that it is embedded in a massive cloud of gas. How massive? This halo made of hot gas is hundreds of thousands of light years across and weighs as much as all the stars in our galaxy put together.
The halo of gas was observed by astronomers through NASA's Chandra X-Ray Observatory.
"Our work shows that, for reasonable values of parameters and with reasonable assumptions, the Chandra observations imply a huge reservoir of hot gas around the Milky Way," said co-author Smita Mathur of Ohio State University in Columbus. "It may extend for a few hundred thousand light-years around the Milky Way or it may extend farther into the surrounding local group of galaxies. Either way, its mass appears to be very large."
The cloud is made up of elements like oxygen and hydrogen. The ratio of each one in relation to each other can help determine the mass of this gas cloud.
Once the size and mass of the halo of gas is confirmed, it could help explain an astronomical mystery known as the case of the "missing bayrons."
Bayrons are essentially made up of particles such as protons and neutrons. The only problem is that current measurements of bayrons seem to only show half of what should be there.
"Although there are uncertainties, the work by Gupta and colleagues provides the best evidence yet that the galaxy's missing baryons have been hiding in a halo of million-Kelvin gas that envelopes the galaxy. The estimated density of this halo is so low that similar halos around other galaxies would have escaped detection," said NASA in a statement.