Dark matter dominates through cosmic time

Dark matter dominates through cosmic time

Young stars (blue) captured by the Hubble Space Telescope, as well as dust (red) from the ALMA submillimeter array are shown in the composite image of a dusty galaxy DSFG850.95 with a star birth.

In a new study, scientists were able to find an unusual galaxy capable of confirming the recently challenged theory of dark matter. Dark matter is a substance that does not emit light, but is determined by the gravitational influence on ordinary matter.

This mysterious substance was first discovered in the 1970s. when studying spiral galaxies whose outer regions rotated too fast to be controlled only by visible stars and gas. Astronomers felt that there should be more invisible mass. Dozens of years of galaxy reviews have shown that in almost all of them there is a huge amount of dark matter. Moreover, it is 5 times more than usual in the Universe.

However, several recent studies have shown that some galaxies do not follow this pattern. A handful of galaxies at a distance of 10 billion light years do not have the expected amount of dark matter. So, at that time, the galaxies could not accommodate a lot of dark matter, but got it somehow later. If this is so, then it will be necessary to reconsider the scientific views on the process of galactic formation. But here is not so simple. Recently, scientists have found a distant galaxy, which seems to be filled with dark matter in accordance with the usual theory. It is distant by 9 billion light years, which means that some galaxies had a large amount of dark matter in the distant past.

For the study, the Keck telescope in Hawaii was used, which made it possible to study the most extreme galaxies with the birth of stars in the Universe (dusty galaxies of stellar birth). The DSFG850.95 galaxy was able to be viewed from an unusual angle, due to which it determined the details of its rotational speed from the center to the marginal territories. The rotation curve allows you to determine the amount of dark matter in the galaxy. So they found out that the volume coincides with the predictions of the theory.

In fact, this is the first accurate confirmation that the situation in the galaxies of the modern Universe occurred earlier. Scientists will continue to study this phenomenon with the help of ALMA to get more information.

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