Researchers say that the Milky Way is surrounded by a halo of hot gas.
Researchers used images and data from NASA's Chandra X-ray Observatory to estimate that the gas cloud encasing the Milky Way is probably about 300,000 light-years across.
“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, professor of astronomy at Ohio State University, reported the Christian Science Monitor.
“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's measurements were made by NASA, the European Space Agency and Japan's space agency.
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The researchers said that the temperature of the hot gas is likely between 1 million and 2.5 million kelvins - many more times hotter than the sun, reported WebProNews.
Scientists hope that the gas cloud could be a way of solving the "missing baryon" problem for the galaxy.
Baryons are sub-atomic particles, like protons and neutrons, that make up nearly 99.9 percent of atoms and it has been estimated that a few billion years ago they represented one sixth of the mass and density of so-called dark matter, said Science Daily.
Currently, scientists say that half of those baryons are missing and unaccounted for.
Some believe that maybe they're hiding in this massive gas cloud, said the Christian Science Monitor.
The findings were published in The Astrophysical Journal.