It is no secret that the universe and our Milky Way galaxy are full of phenomena. However, scientists have discovered something different this time. They spotted mysterious Milky Way clouds that were rapidly moving on a map which covers the entire sky. The high-speed clouds consist of hydrogen and are moving within the usual rotation of our galaxy.
Tobias Westmeier, an astronomer from the International Centre for Radio Astronomy Research, with the help of a high-resolution image of the sky, made an extremely sensitive map of clouds moving at high speed. The map is called the “all-sky map.” He used his new map to highlight the high-velocity hydrogen clouds moving at different speeds through the Milky Way. He published his findings in Monthly Notices of the Royal Astronomical Society.
“These gas clouds are moving towards or away from us at speeds of up to a few hundred kilometers per second,” he said in a press release. “They are clearly separate objects.”
The highlighted, mysterious Milky Way clouds are very large, and they cover up to 13% of the sky. The map unveils details such as the texture and shape of clouds in minute detail.
“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,” he said.
Westmeier also used the sky map to search for the extragalactic origin of some of the discovered clouds.
“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,” he added. “But all the rest, the origin is unknown.”
The Large and Small Magellanic Clouds are tiny dwarf galaxies which orbit our Milky Way. The discovered hydrogen Milky Way clouds are quite close, within roughly 30,000 light years to the “disk” of the Milky Way. The disk is surrounded by a “galactic halo,” as the image below explains. The edge of the galactic halo can spread out up to 180,000 billion light years.
“It’s likely to either be gas that is falling into the Milky Way or outflows from the Milky Way itself,” Westmeier said. “For example, if there is star formation or a supernova explosion, it could push gas high above the disc.”
The good thing is that Westmeier enabled the map to be freely available online to help “the entire community” of astronomers. If you consider yourself an astronomer and think you could have a contribution to deciphering the origin of those clouds, make sure to check the map here.