Mysterious clouds of neutral hydrogen gas in the Milky Way, moving at a different speed to the normal rotation of the galaxy, have been discovered by an Australian scientist who said as much as 13 percent of the sky is covered by them.
The clouds were highlighted in a map covering the entire sky which was developed Tobias Westmeier, of the University of Western Australia, and published this week in the journal Monthly Notices of the Royal Astronomical Society, per the International Center for Radio Astronomy Research.
"These gas clouds are moving towards or away from us at speeds of up to a few hundred kilometers per second," Westmeier said. "They are clearly separate objects."
Westmeier's research used data from the HI4PI survey, a study of the entire sky made public in late 2016, according to the ICRAR. The survey combined observations from the Parkes Observatory in Australia and the Effelsberg 100-meter Radio Telescope.
"It's something that wasn't really visible in the past, and it could provide new clues about the origin of these clouds and the physical conditions within them," Westmeier said in the ICRAR statement.
"We know for certain the origin of one of the long trails of gas, known as the Magellanic Stream, because it seems to be connected to the Large and Small Magellanic Clouds, but all the rest, the origin is unknown," Westmeier continued.
The Hubble Space Telescope has spotted large formations of hydrogen gas in space in the past. In 2016, the telescope gave scientists a look at the massive cloud moving toward the Milky Way galaxy at 702,100 miles per hour with enough gas to create a burst of two million suns, according to Time magazine.
That cloud, though, was not predicted to reach the Milky Way galaxy for another 30 million years, Time reported.
Westmeier said researchers had struggled to agree on the location of the high-velocity clouds.
"We now know that the clouds are very close to the Milky Way, within about 30,000 light years of the disc," Westmeier said. "That means it's likely to either be gas that is falling into the Milky Way or outflows from the Milky Way itself.”