The Milky Way’s little companion provides clues about dark matter Science

The Milky Way is no longer kind to the Milky Way galaxy. Located about 70,000 light-years away, clusters of stars have been shattered by stars in the galaxy’s gravity. Now, scientists have mapped the Sagittarius in great detail, and they have used this map to provide a long-term picture of the state of the mysterious dark matter in which our galaxy resides.

First seen in 1994, the bow is one of Milky Way’s closest allies. Throughout the ages, gravitational forces have separated it, scattering the stars in a current that now completely encircles the Milky Way. This makes the bow a sensitive scale for measuring the distribution of mass in our galaxy, which includes not only the visible disk of stars, but also an invisible hello. Dark matter, Thought of involving up to 90% of the total mass.

Theoretically, researchers could monitor monitor rabbits from nearby star clusters and galaxies and use the laws of physics to determine how much of a case they have. But their speed across the sky is too slow to help in the course of human life. The money stream, on the other hand, already represents those moves. “It’s definitely like a rabbit in the sky for you,” says Vasily Belokrov, an astronomer at Cambridge University.

Over the last quarter-century, astronomers have tried to use money maps to calculate the current shape of the Milky Way’s dark matter. But it is difficult to identify the current from our instability in the disc of the Milky Way, and astronomers are different in the form of eggs and rugby football with light-shapes.

Then came the European Space Agency’s Gaia satellite. Two years ago, the probe began releasing short-translated maps of its stars in the Milky Way and The stars in the surrounding streams. With the statistics, Belokurov and his colleagues could tell that the money stream was being jumped indirectly by another gravity player: the galaxy’s biggest partner, he Large Magellanic Cloud (LMC), which weighs between one-fifth and one-third as much as the Milky Way itself.

Rewinding the clock, researchers sampled Pace de Trosis at 3 billion years It is learned that both LMC and Dhan have bowed near the Milky Way, As 50 million years ago, a significant fracture of the LMC attracted our galaxy, which in turn created a force that affected the sun. Belokurov and his colleagues say it helps explain a strange side path on the money stream, which reports the results in a paper posted to preprint server RXIV. Solving this puzzle made it easier to use the money stream as a current and to determine the current shape of the galaxy’s dark matter. “This is the lock you need before you can unlock the main lock,” says Belokrov.

The team’s findings suggest that the distribution of dark matter around the Milky Way is complex. Near the disk of our galaxy, where the dark matter is expected to be very dense, the halo takes the form of a squash sphere – a little pumpkin-like, the top of the pumpkin pointing out the galactic plane. But about 65,000 light-years away from the galactic center, the hall changes shape: the pumpkin dries on its side, so that its stem aligns with the galaxy’s disk.

Belokurov says that the twists and turns of this intricate shape could provide an indication of how the Milky Way’s halo is connected to the local network of dark matter filaments, called the cosmic web, which surrounds the larger galaxies. Combines.

Catherine Johnston, an astronomer at Columbia University, agrees. “We have never been able to see anything beyond the simple form of dark matter,” she says. “It’s a sign of a major global breakdown, and it’s very interesting.”

It’s important to get this limited view of the Milky Way’s dark matter conditions, says Belokurov, as it approaches us. Hello: This could help researchers understand how many particles of light or heavy dark matter can be. Are, and improve the models that seek evolution. From the big bang of the universe web today.