A huge boomerang from gas returns to our galaxy


    Photo: NASA

    Astronomers working with the Hubble telescope have unveiled an interesting discovery that matches the expression “Everything is back to square one.” Invisible to the naked eye of a person, a cloud of hydrogen moves toward our galaxy at a speed of about 1.1 million kilometers per hour (according to other estimates - about 900 thousand kilometers per hour).

    What could be interesting in a cloud of gas, albeit 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 just one of a kind. There is evidencethat it was thrown out of our galaxy about 70 million years ago. The trajectory of the cloud is well known, and it is named after its discoverer Geila Smith, who discovered the object in the 1960s. Smith spotted the radio waves emitted by hydrogen.

    Cloud Smith will return to the Milky Way in about 30 million years. And when this happens, astronomers expect the appearance of a new star-forming region in our galaxy. About 2 million new stars will be formed here.


    Photo: NASA

    “This cloud is an example of how galaxies change over time,” explains Andrew Fox, one of the scientists studying this formation. “It tells us that the Milky Way is in full swing, there are very active areas from which gas can be ejected outside the disk and then returned,” the scientist continues. The size of the cloud is quite large: 11,000 light years in length and 2,500 in width. If the cloud shone in the visible range, it would be 30 times the size of the full moon in our firmament.

    For a long time, astronomers believed that Smith was mistaken, and this is not a cloud of gas, in fact, but a starless galaxy, or the gas falling on our galaxy from somewhere unknown. 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), scientists came to the conclusion that there are heavy elements in the Smith Cloud. In particular, sulfur atoms, the concentration of which is equivalent to the concentration of sulfur on the outer disk of the galaxy, from where the cloud was ejected many millions of years ago. So we are waiting for the cloud to go home, of course it is a pity that we will not wait for its return.

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