Scientists have captured the first “image” of dark matter

We are finally seeing our lost universe.

Researchers at the University of Waterloo in Waterloo, Ontario, say they have captured the first composite image of something that, although astronomers have talked about it for decades, has until now been unseen and, in fact, undetected. They say it is an image of dark matter, a connecting point in the great cosmic web in which the billions of galaxies in our universe are believed to be embedded. The Royal Astronomical Society, which published the new work in its peer-reviewed Monthly Notices, said in a statement:

“The composite image, which combines a series of individual images, confirms predictions that galaxies throughout the universe are linked through a cosmic web connected by dark matter that until now has remained unobservable.”

Filaments of dark matter bridge the space between galaxies in this false-color map. The locations of the bright galaxies are shown in the white regions and the presence of a dark matter filament linking the galaxies is shown in red. Image via RAS/ S. Epps & M. Hudson / University of Waterloo.

Why do astronomers believe dark matter exists? After all, before this image, no one has claimed to have directly observed it, much less captured its image. However, dark matter occupies a place of honor in astronomical theory; is an integral part of the Lambda Cold Dark Matter model, sometimes called the standard model of Big Bang cosmology, a widely accepted model of how our universe works and a model that agrees well with what astronomers think they see, when they look towards the depths. space.

Some astronomers believe that we do not understand dark matter or believe that it does not exist at all. For example, in 2016, physicist Erik Verlinde of the University of Amsterdam published the latest installment of his new theory of gravity, in which he said that he does not need dark matter to explain the motions of stars in galaxies. Not long after, a team led by astronomer Margot Brouwer of Leiden Observatory in the Netherlands tested Verlinde's theory by examining the lensing effect of gravity around more than 33,000 galaxies. Her team concluded that Verlinde's theory “agrees well” with observations.

That kind of one-two punch is often seen in astronomy. A theory suggests something and observations confirm it (or not). Of course, theories and observations are always flawed and imperfect. What else could they be? Scientists would have to be gods to perfectly understand how the universe works.

So what you'll likely see in the coming weeks, months and years is other astronomers agreeing or disagreeing that this image represents what the University of Waterloo researchers say it represents.

According to the most accepted theories of the universe, dark energy is believed to contribute 73 percent of all the mass and energy in the universe. Another 23 percent is dark matter, leaving only 4 percent of the universe made up of regular matter, such as stars, planets and people. Pie chart via NASA.

In the meantime, know that, according to the most popular models of the universe, dark matter comprises about a quarter of the “stuff” in our universe. This mysterious substance does not glow, absorb or reflect light, although its effects are believed to be recognizable through the workings of gravity. According to these theories, dark matter is integral to the creation of what astronomers call the cosmic web, the basic structure of our universe. In fact, this large network is believed to consist of a network of dark matter filaments. Mike Hudson, the University of Waterloo astronomy professor who led this research, said of his team's work:

“For decades, researchers have been predicting the existence of dark matter filaments between galaxies that act as a web-like superstructure connecting galaxies. “This image takes us beyond predictions to something we can see and measure.”

This often-seen image is an artist's illustration of a honeycomb-like structure, sometimes called a “cosmic web.” The bright areas are clusters and groups of galaxies, with sparsely populated regions devoid of galaxies in between. Since astronomers today believe that galaxies form in a process by which dark matter merges and clumps together, and since dark matter is believed to be much more abundant in our universe than the type of matter that makes up stars and galaxies (and planets like Earth, and people like you and me), dark matter is believed to drive the structure of the cosmic web. Image via Volker Springel, Virgo Consortium.

How did University of Waterloo astronomers get their image of dark matter? Hudson and co-author Seth Epps, a master's student at the University of Waterloo at the time, used a technique called weak gravitational lensing, an effect that causes images of distant galaxies to warp slightly under the influence of an invisible mass like a planet. , a black hole, or in this case – these scientists say – dark matter. They said they measured the effect in images from a multi-year sky survey at the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii.

They combined lensing images of more than 23,000 pairs of galaxies located 4.5 billion light years away to create this composite image or map that they say shows the presence of dark matter between the two galaxies. In other words, it is a dark matter bridge, according to these astronomers. Their results suggest that the bridging of dark matter filaments is strongest between systems separated by less than 40 million light years. Epps said:

“By using this technique, we can not only see that these filaments of dark matter exist in the universe, but we can also see the extent to which these filaments connect galaxies.”

Now let's see if other astronomers can replicate his work and if others agree. If they do, wow… that's amazing!

Bottom line: Astronomers at the University of Waterloo in Waterloo, Ontario, say they have captured the first image of dark matter.