The deformation of the Milky Way disk

The Milky Wayour galaxy, is a vast structure of stars, gas and dust that is home to billions of solar systems. It is often imagined as a flat disk, with spiral arms revolving around a central core. However, recent research has revealed something surprising: the Milky Way’s galactic disk is warped or bent. Far from being a perfectly flat structure, the galaxy actually has a curved shape that has baffled astronomers and raised new questions about its dynamics and evolution.

What is the Galactic Disk?

Before delving into the distortion of the Milky Way, it is important to understand what the galactic disk. Most spiral galaxies, including our own, have a disk-shaped structure. This disk is where most visible matter is found, such as stars and interstellar gas. The galactic disk also houses the spiral arms that characterize these galaxies.

The Milky Way’s disk has a diameter of approximately 100,000 light years and, although it used to be thought to be relatively flat, recent research shows that it is distorted at its periphery.

The Deformation of the Galactic Disk: How and Why is it Bent?

Studies based on observations of the distribution of hydrogen and stars in the Milky Way have shown that the edges of the galactic disk are curved. This curvature is more pronounced as one moves away from the galactic center. The result is that the disk appears to have a shape similar to that of an “S” when viewed in profile.

What Causes This Distortion?

It is still not known with certainty what causes this strange shape, but astronomers have proposed several theories to explain it:

1. Interactions with satellite galaxies: The Milky Way has several smaller satellite galaxies orbiting around it, such as the Magellanic Clouds. The gravity of these galaxies could be pulling on the outer edge of the galactic disk, causing the distortion. This gravitational interaction could warp the disk in the same way that the Moon’s tides affect the shape of oceans on Earth.

2. dark matter: Another theory suggests that the dark matteran invisible form of matter that makes up much of the mass of the universe, could be influencing the shape of the Milky Way. The Milky Way is believed to be surrounded by a halo of dark matter, and if this halo is irregular or rotating, it could distort the galactic disk.

3. Gravitational waves and external disturbances: Collisions or close encounters with other galaxies, which could have occurred in the Milky Way’s distant past, could also have created gravitational waves that affected the shape of the disk. Even after the interaction has ended, the disturbances caused by the collision could continue to ripple through the disk, causing it to bend.

(Photo: NASA/JPL-Caltech/ESO/R. Hurt)

How Was the Folded Shape of the Disc Discovered?

The discovery of galactic disk distortion did not happen overnight. Astronomers have been collecting data on the structure of the Milky Way for decades, but it was advances in observing techniques and the availability of more precise galactic maps that made it possible to see the folded shape of the disk clearly.

One of the most recent studies that confirmed this distortion used satellite data Gaia of the European Space Agency (ESA). Gaia has been collecting detailed information about the position and movement of more than a billion stars in the Milky Way, allowing scientists to create a more accurate three-dimensional map of our galaxy. This map clearly showed that the disk is not flat, but is curved at its edges.

How does this distortion affect the Milky Way?

The distorted shape of the galactic disk has important implications for the dynamics of the Milky Way and for our understanding of how spiral galaxies evolve in general.

· movement of the stars: The stars in the outer regions of the Milky Way not only rotate around the galactic center, but also move up and down due to disk distortion. This could affect calculations about how stars migrate within the galaxy and how the orbits of smaller objects, such as planets, are influenced by the galactic environment.

· Formation of new stars: The distortion could also influence the formation of new stars in the outer regions of the galactic disk. Gravitational perturbations caused by the distortion can trigger compression of interstellar gas, leading to the formation of new stars in certain areas of the disk.

· Galaxy Evolution: In the long term, disc distortion could influence the evolution of the Milky Way. If the distortion is caused by interactions with satellite galaxies or dark matter, it could signal that our galaxy is constantly changing, which could lead to future episodes of galactic growth and reorganization.

The Importance of Understanding Galactic Distortion

Studying the distortion of the Milky Way’s disk not only helps us better understand our own galaxy, but also provides valuable information about how other spiral galaxies in the universe function.

1. Galactic evolution models: By studying the shape and dynamics of the Milky Way, astronomers can improve models of how spiral galaxies evolve over time. This knowledge is essential to understand the life cycle of galaxies and their interaction with their environment.

2. dark matter: If dark matter is playing a role in disk distortion, this discovery could provide new clues about the nature of this mysterious substance. Although dark matter does not interact with light directly, its gravitational influence on galaxies is observable, and better understanding its effect on the Milky Way could help us unravel one of the greatest mysteries in cosmology.

3. Implications for life on Earth: Although galactic disk distortion occurs on a massive scale and does not directly affect life on Earth, understanding how the structure of our galaxy changes over time gives us broader context about our place in the universe and how Galactic environments can influence the formation of stellar and planetary systems.