What is the Great Attractor, where galaxies are heading – 05/24/2023 – Science

A common exercise in school assignments was to put our Solar System in the form of a model.

Thanks to this exercise, we know that the Solar System is a group of planets that revolve around the big golden star. But in these models the Sun was static and floating in the immensity.

However, astronomers have been pointing out for decades that the Solar System, and especially our galaxy, the Milky Way, is hurtling across the vast expanse of the universe at around 600 kilometers per second.

And it has also been known for a long time that this journey has a destination.

Discoveries made in the 70’s by a group of astronomers determined the existence of a “great force” whose origin would be the destination of the journey that the galaxy is currently making. This force was called the Great Attractor.

“Our galaxy is heading toward something we can’t clearly see. The focal point of this motion is the Great Attractor, the product of billions of years of cosmic evolution,” explains cosmologist Paul Sutter, professor of astrophysics at Stony Brooks University in New York. York, to BBC Mundo (BBC Spanish service).

And despite the impressive speed at which our galaxy travels, it probably won’t reach the destination defined by the Great Attractor.

“We will never reach our destination because, in a few billion years, the accelerating force of dark energy will destroy the universe,” explains Sutter.

Dark energy, as NASA explains, is a mysterious force that permeates the cosmos and accelerates the expansion of the universe.

This translates into galaxies moving further and further away from each other, until in billions of years the structure of the universe as we know it today is destroyed.

Therefore, understanding the effects of the Great Attractor has to do with the effort to understand the structure of the universe.

“Within the study of the universe, it is very important to know how it is organized, because it is arranged based on structures that have certain sizes, and knowing each one of them and their size helps a lot in this endeavor”, says Carlos Augusto Molina, a Colombian astrophysicist who works at the Bogotá Planetarium, for BBC Mundo.

how it was discovered

As space exploration progressed, thanks in large part to the launch of the Hubble telescope in the second half of the 20th century, astronomers faced the challenge of somehow organizing everything they were seeing.

A kind of map began to be drawn and, of course, one of the fundamental points was to know where our Solar System and our galaxy are located in the universe.

“Around the 1970s, we started to study the movement of our Solar System, of our galaxy, and we compared it with the movement of other nearby galaxies, and everything seemed to go in the same direction as the expansion of the universe”, explains Sutter.

“However, astronomers began to notice something curious: there seemed to be a vague directionality beyond this expansive movement, as if all the galaxies close to us were also heading towards the same focal point,” he adds.

For many astronomers, this “direction” had to do with defects in the observations or other factors that led to an erroneous reading of the information they received.

But telescopes were improving their technologies and, around 1986, science was able to determine that in fact the closest galaxies, including ours, were walking in a common direction.

“With these new instruments, astronomers are able to determine not only that we were moving towards a concentration of matter, but also the speed with which we were doing this. In other words, they were able to establish with certainty what it was”, points out Molina.

In this sense, although it cannot be determined exactly, one of the main theories points to the fact that the Great Attractor is a large structure of dark matter located within the supercluster of galaxies known as laniakea and that has the capacity to attract galaxies in a radius of more or less 300 million light years away.

Dark matter is another enigmatic component of the universe.

It is a type of matter that cannot be observed, one can only intuit that it exists due to the gravitational effect it exerts on objects in the cosmos.

This large concentration of matter that drags the galaxies was called the Great Attractor, which is located about 200 million light years from Earth.

One of the reasons Sutter has been dedicated to studying more about the Great Attractor is that, despite advances in astronomical observation, this superstructure remains a mystery.

“One of the big disadvantages of knowing more about the Great Attractor is that it is located in a very inconvenient position: completely on the opposite side of our galaxy,” he says.

“When we try to observe there is a lot of noise: many stars, planets, nebulae in the middle that do not allow a more complete analysis of this force that attracts us.”

It’s not a black hole

Both Sutter and Molina make it clear that the Great Attractor is not a black hole, pointing out that it is a gravitational anomaly.

“It’s a totally different force and there’s no connection to black holes in the universe,” says Sutter.

The truth is that, by being able to determine this, it was also possible to establish that there were other similar anomalies in other parts of the universe that would have a similar function: dragging galaxies.

“Knowing this helps us in a fundamental task for understanding the universe: how it is made up of these structures that we classify or hierarchize according to their gravitational capacity”, says Molina.

For Molina, “mapping” the universe is done by learning more about how these areas interact with other forces, such as light or gravity.

“Knowing this structure allows us to compare how processes such as interaction with light —or not— or its density occur in similar structures in other galaxies in the universe”, he adds.

Another important aspect is that it allows us to study the “future” of our space environment.

“Knowing how fast our galaxy is moving and where it’s going allows us to think about or study aspects of how it will behave in the future,” notes Sutter.

However, while from these developments we know the destination of this journey the galaxy is on, we also know that Earth or our Solar System may very well not be able to see the end.

“There is another very powerful force in the universe that we call dark energy, which is the complete opposite of gravitational: instead of pulling, it pushes,” says Sutter.

“So when we actually approach the Great Attractor in a few million light years from now, this dark energy, which we know very little about, is going to have an effect on that trip, which is very possibly the destruction of everything we know.” concluded the scientist.