Since the sixties of the last century, cosmologists have recorded an important observation, which is that the vicinity of our Milky Way galaxy contains a very small number of galaxies similar to it. This observation has remained a great mystery since that time, but a team of researchers led by scientists from the Finnish University of Helsinki recently arrived at a solution. she has.
The Milky Way is a spiral galaxy consisting of a center in the form of a short, bulging rod and spiral arms with a diameter of about 100,000 light-years. The thickness of the arms approaches 1,500 light-years, and at the bulge center it may reach 4,000 light-years.
The Milky Way is among hundreds of other galaxies within the so-called Virgo Supercluster, a sheet of galaxies a billion light-years across, but spiral galaxies like our own are remarkably rare along this giant plane, while elliptical galaxies are more common.
Elliptical galaxies are the most advanced galactic systems in the universe. They do not contain arms, and when scientists observe them, they do not find in them any gas or dust that could create new stars like spiral galaxies, while we find that their stars tend to be red in color, which means that they are large stars. In age compared to white stars like the Sun.
A telescope image of an elliptical galaxy called NGC 2865. This type of galaxy represents 60% of the galaxies in the universe (NASA)
solve the puzzle
According to the study published by this team in the journal Nature Astronomy, they resorted to a “simulation of the local beyond the universe,” or what is known as “Sibelius” for short, which is run on a number of supercomputers in England and Finland.
The results came to say that the reason for the presence of a greater number of elliptical galaxies in our cosmic surroundings is the violent history of repeated galactic collisions in this region since the beginning of this universe about 13.8 billion years ago.
Through simulations, the researchers found that spiral galaxies in dense galaxy clusters often collide catastrophically with each other, crushing their arms and smoothing them out into elliptical galaxies.
According to the study, this process pushed more star matter into the giant black hole at the center of the galaxy, making the black holes larger and consuming a lot of galactic matter.
It is known that galactic mergers are common in the universe, and when two spiral galaxies merge together, they turn into a giant elliptical galaxy. According to the study, this has been more common over billions of years in our cosmic environment, but it does not represent an anomaly.
A video showing the scenario of our galaxy colliding with its neighbor, the Andromeda Galaxy.
The fate of our galaxy
In fact, our Milky Way galaxy is now on its way to merging with the closest galaxy to us at a distance of 2.5 million light-years, which is the “Andromeda” galaxy, which is twice as large in size as our galaxy, as the two galaxies are approaching each other at a speed of about 300 kilometers per second. .
Despite this tremendous speed, the two galaxies would need approximately 4 billion years for the collision to occur, according to study It was issued in 2012 by a research team of Hubble Space Observatory astronomers.
According to this study, two billion years from now, the Andromeda Galaxy will come so close to us that it will become possible for it to appear clearly in the night sky as the moon for almost all of Earth’s inhabitants, if the human race is destined to live until that moment.
In general, spiral galaxies are the young stage of a galaxy’s life, after which they grow up to become elliptical galaxies, which now represent 60% of the number of galaxies we know in the universe.
This indicates that the universe has now already finished building the majority of new stars, and it is believed that only about 5 billion years remain until the process of building new stars completely stops in the universe.
