Andromeda Galaxy

*This text was written by a columnist from TecMundo; learn more at the end.

When we look up beyond the limits of our planet, the Universe opens into a glorious picture. we look at the Solar system and all the celestial bodies that compose it, to the myriad of distant stars and to the splendor of our galaxy.

Over billions of years, atoms have come together and recombined through countless physical processes to give rise to all the ordinary matter that makes up the Cosmos, from the smallest speck of interstellar dust to the largest of galaxies.

THE Milky Way it is just one of more than 1 trillion galaxies that astronomers estimate exist. A huge number of satellite galaxies accompany us on our cosmic journey, orbiting us over millions of years. Our most exuberant neighbor, the Andromeda galaxy, surpasses us in size, in mass and even in the number of stars. It and the Milky Way are so close together that a collision within the next 4.5 billion years is inevitable.

Andromeda GalaxySource: Robert Gendler

Altogether, our galactic neighborhood is made up of about 60 galaxies gravitationally bound to an environment known as the Local Group. This cluster of galaxies is, in turn, located on the outskirts of an even larger cluster, called the Virgo Cluster, made up of about 1,300 galaxies.

Possessing a galactic neighborhood, however, is not a Milky Way privilege. Most galaxies in the Universe are found joined together in large numbers in groups and clusters of galaxies, one of the largest gravitationally bound structures in existence. Among these large structures it is common to find huge regions of cosmic voids containing very small amounts of matter in their interior.

Galaxy cluster Abell 370.Galaxy cluster Abell 370.Source: NASA/ESA/Hubble

These regions were discovered in 1978 and have diameters that vary between 10 and 400 million light-years. The origin of these voids is believed to date back to small fluctuations in matter density in the early universe, when it was less than 1 million years old.

Within these enormous voids, one eventually finds the occasional lone galaxy, unlucky compared to most others in the Cosmos. One of the most notable examples of this fact is the galaxy MCG+01-02-015, the only one within 100 million light years in either direction. This makes it the loneliest galaxy in the Universe ever discovered and, thanks to science, it is possible to predict what and how its final destination will be.

Schematic representation of cosmic voids between superclusters of galaxies.Schematic representation of cosmic voids between superclusters of galaxies.Source: Wikimedia/u/Zephyrex

Distant about 290 million light-years from the Milky Way, MCG+01-02-015 is a huge spiral galaxy that is located in the direction of the constellation Pisces in the night sky. It is so far from any other galaxy that, if our galaxy had been in its place, humanity would only have discovered the existence of other galaxies in the 1960s (this was confirmed in 1923), with the advent of more sophisticated and powerful telescopes. .

Unlike other galaxies, MCG+01-02-015 will see distant galactic groups and clusters move further and further away, accelerating further and further away. It will remain isolated, forming stars in large numbers along the regions lining its spiral arms for as long as there is new material to form new stellar generations.

In the next tens of billions of years, every galaxy that can be seen will accelerate, leaving only a few photons behind. After 100 billion years, astronomers of some civilization on MCG+01-02-015 will have no observational indication that other galaxies ever existed. The rate of new star formation will fall and continue to fall, until all the stars have burned up all their fuel. The remaining white dwarfs, the dead remnants of most of these stars, will eventually disappear to become black dwarfs as they cool to become completely invisible. At that point, the galaxy will be considered “dead”.

MCG+01-02-015MCG+01-02-015Source: NASA/ESA/Hubble

Finally, after eons and eons into the distant future, the loneliest galaxy in the Universe will appear completely empty. No stars, no stellar remnants, no planetary corpses or even black holes are to remain. But still, it will exist. Someone who could measure the curvature of the Universe’s spacetime or somehow detect dark matter (or, more technically, ultra-low-energy neutrinos) would find a large, diffused halo of mass that will persist much longer than any other structure ever made. of ordinary matter.

In this way, the lonely MCG+01-02-015 will have, like all the phases of her life, a lonely end.

Nícolas Oliveiracolumnist for TecMundo, holds a degree in Physics and a master’s degree in Astrophysics. He is a professor and is currently doing his PhD at the National Observatory, working with galaxy clusters. He has experience with Teaching Physics and Astronomy and with research in Extragalactic Astrophysics and Cosmology. He works as a scientific disseminator and communicator, seeking the popularization and democratization of science. Nícolas is present in social networks as @nicooliveira_.

Leave a Reply