A mysterious trail of stars, caused by a small galaxy about to collide with the Milky Way, may be about to reveal the secrets of dark matter.
A trail of stars located outside the star-strewn spiral arms of the Milky Way’s central disk in an area called the galactic halo is being swept away in the cosmic stream of a dwarf galaxy orbiting the Milky Way, according to a new study. the sky map was created by astronomers.
The galaxy, dubbed the Large Magellanic Cloud (LMC), is in orbit about 130,000 light-years from Earth. land and awakening a cosmic trail behind me. At first glance, it might seem that the LMC trail is composed entirely of stars, but the researchers know that the stars are just traveling. They are suspended within a much larger, completely invisible presence.
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Astronomers are interested in this ripple in space because they think it might be composed of dark matter - a mysterious non-luminous substance that makes up the overwhelming majority of the matter in the Universe. Dark matter, invisible and interacting with matter that we see only through gravity, is predicted to be everywhere in the galactic halo.
“We think that this trail is made of dark matter and carries stars with it, which is why we can detect it,” - said study co-author Nicholas Garavito-Camargo, a doctoral student at the University of Arizona. said in a statement…
The gravitational influence of dark matter can be observed throughout the universe: it is the vital forests of our galaxy, gluing stars and planets to it so that they do not fly away when the galaxy rotates. Yet what dark matter is and how it behaves remains one of the greatest mysteries of astronomy. The researchers hope that by studying the trail, they will be able to study dark matter, which they believe makes up the vast majority of it.
If the stars in the trail are like leaves floating in a pond of dark matter, how the leaves were disturbed by the boat (in this case, the LMC) can tell us a lot about the pond itself.
“You can imagine that the trail behind the boat will be different if the boat is moving on water or honey,” said lead author Charlie Conroy, professor of astronomy at Harvard University. “In this case, the properties of the trace are determined by which theory of dark matter we apply.”
The group used their new map and track position to confirm a theoretical model created by another group of researchers about how dark matter should be distributed across the galactic halo; they are now conducting tests to see which of the theories about dark matter best matches the shape and location of the trail.
The map, based on data from NASA and the European Space Agency (ESA) telescopes, also provides some important clues about the harsh future of our home galaxy. As the LMC orbits the Milky Way, the gravitational pull of dark matter in the Milky Way’s galactic halo slows it down, sending the LMC into smaller and smaller orbits. The LMCs will continue to wind closer to the Milky Way until they collide in about 2 billion years.
The merger of two galaxies is surprisingly common in the universe. The Milky Way probably merged with a small galaxy 8 billion years ago, and merging galaxies is a key reason for the growth of all large galaxies.
“This stealing of the energy of a smaller galaxy is not only the reason for the LMC’s merger with the Milky Way, but also the reason for the merger of all galaxies,” said study co-author Rohan Naidu, a graduate student at Harvard University. “The footprint on our map is really good confirmation that our basic picture of galaxy mergers is correct.”
The researchers published their findings on April 21 in the journal. Nature…
Originally published on Live Science.
