According to the results of a new study, ourthe galaxy is made up of a halo of dark matter that surrounds the disk of the Milky Way. Recall that dark matter is the most mysterious substance in the Universe that cannot be seen and which appears only during the gravitational interaction of space objects. Recently, astronomers from Durham University have calculated the true size of our galaxy by studying the gravitational attraction of smaller neighboring galaxies. The disk of the Milky Way consists of stars, black holes, planets and other celestial objects and extends across 260,000 light years. At the same time, the rest of the Milky Way consists of an invisible “halo of dark matter” - a huge sphere of dark matter enveloping the galactic disk. Having compiled a detailed 3D map of dark matter around the Sagittarius A * supermassive black hole, scientists determined that the halo of dark matter extends for 950,000 light years, as in other galaxies of the same size.
Halo of Dark Matter Is a hypothetical component of galaxies that surrounds a galactic disk, extending far beyond the boundaries of a visible galaxy.
Secrets of the Milky Way
After observing unusually fast speedThe movement of stars on the outer edge of the disk of our galaxy, astronomers have discovered that the Milky Way is surrounded by a sphere of dark matter. Recall that dark matter can only be detected by the influence of its gravity on other objects - however, dark matter cannot be seen, since it does not interact with photons - particles of light. A group of researchers led by astrophysicist Alice Dyson of Durham University decided to find out how far this sphere of invisible matter actually stretches from the edge of the Milky Way disk. “In many studies of the halo of the Milky Way, its outer border is a fundamental limitation,” the authors of the study write.
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In the course of their work, scientists used data onthe interaction of dark matter with surrounding objects. As a result, they managed to create a virtual map of a local group of galaxies - a set of galaxies with a diameter of about 9.8 million light years, including the Milky Way and our closest galactic neighbor, the Andromeda galaxy. This simulation allowed us to see how the Milky Way dark matter halo will look and interact with other objects. It turned out that outside the halo of dark matter, the radial velocity — the orbital velocity of objects moving around the galaxy — decreases markedly.
Scientists have compared simulated data withreal observations of nearby dwarf galaxies. The fact is that astronomers cannot observe the entire Milky Way, since we are inside the galaxy. And observations of other galaxies of the local group coincided with the simulation and proved a sudden drop in radial velocity, which allowed us to calculate the diameter of our galaxy. In dwarf galaxies, this boundary is 950,000 light years. The authors of the study believe that in the future they will be able to more accurately measure the edges of the Milky Way and nearby galaxies of the same mass. The work will be published in the journal Monthly Notices of the Royal Astronomical Society. You can familiarize yourself with the work on the arXiv preprint server.
What is dark matter?
- Dark matter makes up about 27% of the universe. It is invisible because it does not reflect light.
- Despite the fact that dark energy cannot be seen directly through telescopes, astronomers know that it is there because of the gravitational effect that it exerts on visible matter.
- Dark matter is believed to bethe gravitational “glue” that holds the galaxies together, while only 5% of the universe is made up of known material, such as atoms and subatomic particles.
In general, our site has excellent material onthe theme of what dark matter is. This mysterious form of matter, which literally “sticks together” galaxies among themselves, has been studied by scientists for many years and, in our opinion, everyone should know about their successes.