A huge "boomerang" of gas returns to our galaxy

Photo: NASA

Astronomers working with the Hubble telescope, unveiled an interesting discovery, which corresponds to the expression "Everything is back to square one." The hydrogen cloud, invisible to the unaided human eye, moves towards our galaxy at a speed of about 1.1 million kilometers per hour (according to other calculations - about 900 thousand kilometers per hour).

What could be interesting in a cloud of gas, start up and moving at such a speed? There are many similar objects, and it is difficult to call them unique. The fact is that this cloud, called " Cloud Smith " is one of a kind. There is evidence that it was ejected from our galaxy about 70 million years ago. The trajectory of the cloud is well known, and it is named after its discoverer Gayle Smith, who discovered the object in the 1960s. Smith spotted radio waves emitted by hydrogen.

Cloud Smith will return to the Milky Way in about 30 million years. And when this happens, astronomers expect a new star-forming region to appear in our galaxy. There should be about 2 million new stars.
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Photo: NASA

“This cloud is an example of how galaxies change over time,” explains Andrew Fox, one of the experts studying this formation. “It tells us that the Milky Way is boiling, there are very active areas from which gas can be thrown out of the disk, and then returned back,” the scientist continues. The size of the cloud is large enough: 11,000 light years in length and 2500 in width. If the cloud shone in the visible range, it would be 30 times the size of the full moon in our sky.

For a long time, astronomers believed that Smith was wrong, and this is not a cloud of gas, in fact, but a starless galaxy, or a gas falling on our galaxy from somewhere out of obscurity. If this were true, hydrogen and helium would be detected in the cloud, without the heavier elements created by the stars. Well, otherwise, in this cloud should be other elements that are characteristic of our Sun.


Photo: NASA

After a detailed study of the spectrum of the cloud (carried out by analyzing the ultraviolet radiation of three distant galaxies passing through the cloud), the scientists came to the conclusion that there are heavy elements in the “Smith cloud”. In particular, sulfur atoms, whose concentration is equivalent to the sulfur concentration on the outer disk of the galaxy, from where the cloud had been ejected many millions of years ago. So we are waiting for the cloud to go home, it's a pity, of course, that we will not wait for his return.