What are the giant arcs of galaxies, the largest structures in the universe that challenge what we know about the universe

known as the giant bow, Hulk questions some basic assumptions about ordiverse.

According to the Standard Model of cosmology, the theory on which our understanding of the universe is based, matter should be more or less evenly distributed in space.

When scientists look at the universe on very large scales, there should be no noticeable imbalances; Everything should look the same in all directions.

However, the Giant Arch is not the only example of its kind. These gigantic structures are now forcing scientists to Re-evaluating his theory of how the ordiverse.

Lopez was studying for her master’s degree at the University of Central Lancashire in the United Kingdom when her supervisor suggested using a new method to analyze large-scale structures in the universe.

Use quasars — distant galaxies that emit an extraordinary amount of light — to search for ionized magnesium, a sure sign of gas clouds surrounding a galaxy.

When light passes through this ionized magnesium, certain frequencies are absorbed, leaving unique optical “signals” that astronomers can detect.

“I examined known and documented galaxy clusters, and then began to map out the shape of these regions in the Magnesium II method,” says Lopez.

“One of the clusters I noticed was very small, but when I drew it in Magnesium II, there was this interesting, dense band of magnesium uptake across my entire field of view. That’s how I ended up spotting it. It was a happy accident and I was lucky I was the one to find it.”

What Lopez discovered with the “happy accident” was amazing. Looking towards the constellation Bootes, a group of 45 to 50 gaseous clouds, each associated with at least one galaxy, appears to be organizing itself. In an arc 3.3 billion light-years wide.

That’s a lot considering the observable universe is 94 billion light-years in diameter.

According to Lopez’s paper, it is extremely unlikely (just 0.0003 percent probability) that such a large structure could have arisen by chance.

It is suggested that it may have formed Because of something in the natural physics of orThe universe that we don’t currently take into account.

Their results directly challenge a key facet of the standard cosmological model: the best explanation we have of how the universe began and evolved.

This facet, known as the cosmological principle, states that on a broad scale, the universe should look pretty much the same everywhere, no matter where you stand or what direction you look.

There should be no giant structures, but the space should be smooth and uniform. This is convenient, as it allows researchers to draw conclusions about the entire universe based solely on what we see from our location.

It makes sense, too, that after the Big Bang, the universe expanded outward, spewing matter in all directions at once.

There is another problem. According to the Standard Model, structures such as Giant Arch They simply did not have time to form.

“The current idea of ​​how structures form in the universe is through a process known as gravitational instability,” says Subir Sarkar, professor of theoretical physics at the University of Oxford.

About a million years after the Big Bang, when the universe was expanding, small fluctuations in density caused bits of matter to clump together.

Over billions of years, the pull of gravity eventually formed these clusters of stars and galaxies.

but, There is a limit to the size of this process. Anything larger than about 1.2 billion light-years across would not have had enough time to form.

“For structures to form, you need the particles to be packed close to each other so that gravitational collapse can occur,” says Sarkar. “These particles have to move in from outside the structure to get there.”

“If your structure spans 500 million light-years, it would take 500 million years to get from one end to the other.”

“However, the particles we are talking about move much slower than light, so it would take billions of years to create a structure of this size, and the universe has only existed for about 14 billion years.”

The giant arch discovered by Lopez wasn’t the only large structure discovered by astronomers.

There is the Great Wall of China (also known as the CfA2 Great Wall) which was discovered in 1989 by Margaret Geller and John Hochra.

The wall is about 500 million light-years long, 300 million light-years wide, and 15 million light-years thick.

The largest is the Sloan Great Wall, a cosmic structure consisting of a giant wall of galaxies, discovered in 2003 c.

this wall It is approximately 1.5 billion light-years away.

In the past decade, the discovery of these giants has accelerated further. In 2014, scientists discovered the Laniakea Supercluster, a group of galaxies in which our Milky Way galaxy resides.

Lancia is 520 million light-years in diameter and contains approx The mass of 100,000 trillion suns.

Then, in 2016, the BOSS Great Wall, a galactic complex spanning more than a billion light-years, was discovered. BOSS consists of 830 separate galaxies that have been pulled by gravity into four giant clusters.

Galaxies are connected by long filaments of hot gas. In 2020, the Antarctic Wall, which stretches across 1.4 billion light-years, was added to the list.

However, the current record holder for the largest of these structures is the Hercules-Corona Borealis Great Wall.

Discovered in 2013, it spans 10 billion light-years. More than a tenth of a size orvisible universe.

We figured it out and then we realized, ‘Oh, oh, This is the biggest or“diverse”says John Hakila, professor of physics and astronomy at the University of Alabama in Huntsville.

His concern was justified. Haquila and Lopez ran a series of statistical tests to try to show that the results could not be due to chance.

For the giant arc, the results have a confidence level of 99.9997%. In scientific research, the gold standard for statistical significance is known as 5-sigma, which equates to a 1 in 3.5 million chance that the results were due to chance.

Giant Arc has reached significance of 4.5 sigma, so there is still a chance for that The structure is a random arrangement of stars.

“Our eyes are very good at seeing patterns. You may see initials in clouds, but that’s not real structure, your brain is forcing structure on what’s actually random,” Sarkar explains.

“However, I don’t think that’s the case in this case, I think it’s a real physical chain of giant clusters.”

If more structures like the Giant Arch and Hercules-Corona Borealis Great Wall are proven to exist, astronomers will have to rewrite or at least revise the Standard Model of cosmology.

This wouldn’t be the first time the model had to be adapted. In 1933, Caltech scientist Fritz Zwicky measured the mass of a galaxy cluster and found that the number was lower than expected.

In fact, the cluster was so small that the galaxies had to pull away from each other and escape the cluster’s gravity.

So, Another thing that should bring clusters of galaxies together.

This “something” is dark matter, a mysterious substance believed to make up 27% of the universe.

Then, in 1998, the model was revised to include dark energy, after two independent teams of astronomers measured the expansion of the universe and found that it was accelerating.

Either way, we should definitely know in the next few years. The Legacy Space and Time Survey (LSST), a planned 10-year survey of the Southern Hemisphere sky, may provide astronomers with an unprecedented view of the universe.

“It takes a lot to make a paradigm shift happen, especially when people invest their lives and jobs in it, but in the end with science we have to prove who is right,” says Sarkar.

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