The Universe is not only endless expanses of darkness and trillions of galaxies containing many billions of stars and many billions of planets. In fact, everything is much more complicated here. Each separately taken galaxy, as well as a separately taken galaxy cluster, is connected with the so-called giant intergalactic web, whose invisible threads are made of dark matter. We understand that this is rather difficult to imagine, but quite recently, scientists, thanks to a very clever way of using the method of gravitational lensing, were able to see some of these threads.
By comparing information about galactic groups that act as galactic lenses with information about light sources located behind these groups, a team of astronomers from the University of Waterloo in Canada took advantage of the ability of dark matter to distort space and were able to see what they could not see before.
If we take the most powerful telescope and look into space, then everything that we see directly will be only 5 percent of the universe we observe. Another 68 percent is some kind of energy. We know little about it (even the best physicists of our time cannot cope), but we know that it exists, thanks to the effect it has on the surrounding space. Science calls this power "dark energy". There is also dark matter, which accounts for 27 percent of the universe we observe. We also know practically nothing about this matter, but again we know that it is, due to the fact that it, like dark energy, affects the space around it. The effect of exposure in both cases is gravity. The difficulty in studying dark matter is, among other things,that she practically does not show herself in any way. Ordinary matter with mass is capable of releasing or absorbing electromagnetic radiation, or at least interacting with nuclear forces. Dark matter is a different case. They affect the surrounding tissue of the Universe only by their gravity.
Previously, scientists could only guess where the clusters of dark matter might be. Calculations, as a rule, were carried out by mapping stars and galaxies, and then determining what mass they should have, taking into account their movement and location in the space of the Universe. The data indicated that ordinary matter and dark matter tended to be together and often form clumps, the presence of which was hinted at by the emerging halo effect near large clusters of intergalactic gas or dust. Moreover, more dark matter in these clumps has always been predicted than usual. Nevertheless, science also knows that dark matter not only forms clumps, but also stretches into very long threads that permeate the entire universe like a spider web. Galaxies often cling to these strandsforming giant galaxy clusters stretching not only space but also time.
But knowing about the presence of dark matter between visible galaxies is one thing. Seeing her is quite another.
“For decades, scientists have predicted the existence of dark matter filaments between galaxies that act like a spider web, linking these galaxies together,” explains researcher Mike Hudson.
“But the image we got is much cooler than conventional predictions. This is what we can see and measure."
When light passes through matter with a large mass, such as a galaxy, the light begins to distort under the influence of gravitational forces. By comparing various images of 23,000 pairs of galaxies located about 4.5 billion light-years away, astronomers were able to compile a relatively detailed map of the dark matter filaments that unite these galaxies. Moreover, scientists were able to not only determine the presence of these filaments, but also found out some of their characteristics.
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“We were able not only to note the presence of these dark matter filaments, but also to find out some of the features of these screeds,” the scientists comment.
For example, the strongest filaments of dark matter are found between galaxy clusters less than 40 million light-years apart.
In the future, adding this data to the existing models and maps of dark matter can provide us with additional information about this mysterious substance and, possibly, even expand our knowledge of the evolution of the Universe.
NIKOLAY KHIZHNYAK