Galaxies Discovered That Challenge the Main Model of the Universe
The ideal arrangement of galaxies in a nearly straight line contradicts the basics of a cosmological model of the Universe called the Lambda-CDM model.
Astronomers have discovered a group of five dwarf galaxies that, to the surprise of scientists, are located almost in a straight line in space, with most of them rotating in the same direction.
Such features cannot be explained by the leading model of the Universe based on the existence of cold dark matter, called the Lambda-CDM model. The study is published in The Astrophysical Journal Letters.
The Lambda-CDM model suggests that dark matter, a mysterious invisible form of matter, helps hold large-scale structures like galaxies together using gravity. Dark matter helped these galaxies form in the early universe.
According to the leading model of the universe, dark matter causes galaxy groups to appear disordered. That is, galaxies should not be arranged in nearly a straight line in space.
However, astronomers have discovered five strangely connected galaxies that are located in an isolated region of space about 117 million light years away. The galaxies are arranged in a nearly vertical line from north to south on a three-dimensional map of space.
Scientists have also found that three of the five galaxies have the same direction of rotation. Their northern parts are moving away from us, while their southern parts are moving toward us.
They believe that the best explanation for the strange features of the galaxies linked together is that they were created from the same clump of gas. But this contradicts the concept of cold dark matter, which is the basis of the Lambda-CDM model, which describes the evolution of the Universe. Galaxies, and especially dwarf galaxies, cannot have such an arrangement.
The exact distances to the galaxies are unknown, making it difficult to construct a complete 3D picture of their positions in space, scientists say. But if the galaxies are aligned, it is likely that this can be explained by warm dark matter rather than cold dark matter.
This is a hypothetical form of dark matter whose particles are different from those of cold dark matter, especially when it comes to how they came together in the early universe.
Astronomers say warm dark matter particles don’t clump together as well as cold dark matter particles, which could have helped galaxies form from the same gas cloud. As a result, the galaxies become more synchronized with each other, both in position and rotation, leading to their strange connection.
But no evidence of warm dark matter has been found yet, and the Lamb-CDM model is still based on cold dark matter. If more such galaxies are found, the main model of the Universe will have to be revised, scientists believe.
