Just outside the plane of the Milky Way, strange and huge clouds of hydrogen are making their way through intergalactic space at incredible speeds. Scientists have known for some time that these mysterious objects exist, but only recently have they been mapped in great detail.
Everything about these clouds speaks to its large scale. Some of the clouds are millions of times the mass of the Sun and extend over tens of thousands of light-years in diameter.
Hydrogen clouds cover about 13 percent of the night sky but they needed the powerful radio telescopes used by Australia scientists at the International Radio Astronomy Research Center (ICRAR) to look inside them. The new data allowed researchers to build a much more detailed map of the clouds that now shows features never before seen as groups and structures similar to branches.
"It's something that was not really visible in the past, and could provide new clues about the origin of these clouds and the physical conditions within them," said Tobias Westmeier, one of the ICRAR researchers involved in the new research , it's a statement.
What makes these clouds particularly interesting, but challenging, to study is the fact that they move differently from the rotation movement of the galaxy itself. Traveling at speeds of 43.5 to 56 miles per second, the clouds also seem to be in a hurry to get closer or away from us.
It is not at all clear at this point how the clouds came here or why they behave the way they do. It could be that odd objects are remnants of the formation of the galaxy itself. Alternatively, they could be obtained from some alien galaxy only to be caught in the gravitational embrace of the Milky Way. This last hypothesis seems to have more weight given that the chemical composition of the hydrogen-rich clouds differs from what you would normally expect to find within the Milky Way.
Maybe you, dear reader, can help answer this question. The map is available online for anyone to study.
The new findings appeared in the Monthly Notices of the Royal Astronomical Society.
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