A massive effort by a huge international team of scientists has just given us the most accurate map of all matter in the universe ever obtained.
By merging data from two major surveys, the international collaboration revealed where the universe does and doesn’t hold all of its trash — not just the ordinary matter that makes up planets, stars and dust, black holesGalaxies, however dark matterAlso: the mysterious invisible mass that generates more gravity than ordinary matter can explain.
The resulting map, which shows where matter has accumulated over the universe’s 13.8 billion years, will be a valuable reference for scientists looking to understand how the universe evolved.
In fact, the results have already shown that matter is not quite as distributed as we thought, which indicates that there may be something missing from the stream. Standard Model of Cosmology.
According to current models, at a point the great explosionAll matter in the universe was condensed into a single state: a single point of infinite density and intense heat that suddenly exploded and released quarks that quickly combined to form a soup of protons, neutrons, and nuclei. Hydrogen and helium atoms came about a few hundred thousand years later. Of these, the entire universe was made.
How these early atoms spread out, cooled, and clump together, forming stars, rocks, and dust, is an investigative business based on how the universe around us appears today. And one of the main clues we used is where all this matter is now – because scientists can then work backwards to figure out how it got there.
But we can’t see all of that. In fact, most of the matter in the universe — about 75 percent — is completely invisible to our current detection methods.
We’ve only detected them indirectly, because they create gravitational fields that are stronger than they should be based on the amount of normal matter. This manifests itself in phenomena such as galaxies spinning faster than they should, and a small oddity in the universe we call it gravitational lens.
When something in the universe has enough mass—say, a group of thousands of galaxies—the gravitational field around it becomes strong enough to affect the curvature of space-time itself.
This means that any light that travels through that region of space does so along a curved path, resulting in distorted and amplified light. These lenses are also stronger than they should be if they were only created with regular material.
To map matter in the universe, the researchers compared gravitational lensing data collected by two different surveys – Dark Energy Survey, which collected data at the near-ultraviolet, visible, and near-infrared wavelengths; and the South Pole Telescopewhich collects data about Cosmic microwave backgroundthe faint traces of radiation left over from the Big Bang.
By cross-comparing the two sets of data taken by two different tools, the researchers can be more confident in their findings.
“It works like a cross-check, so it becomes a much more powerful measurement than if you just used one of them,” she says. says astrophysicist Shihuai Zhang of the University of Chicago, who was the lead author of one of three papers describing the work.
The lead authors on the other two papers are physical Yuki Ohori From the Kavli Institute for Cosmological Physics and the University of Chicago and Telescope Scientist Tim Abbott From NOIRLab’s Cerro Tololo Inter-American Observatory.
The resulting map can then be extrapolated, based on the positions of galaxies, galactic lensing, and cosmic microwave background lensing, to infer the distribution of matter in the universe.
This map can then be compared to models and simulations of the evolution of the universe to see if the observed distribution of matter matches the theory.
The researchers ran some comparisons, and found that their map mostly matches existing models. But not quite. There were some slight differences between the observation and the prediction. The researchers found that the distribution of matter is less lumpy and more spaced than the models predict.
This indicates that our cosmological models could use a tweak.
This isn’t really a surprise – there are quite a few discrepancies between cosmological observation and theory that seem to suggest We’re missing a trick or twoSomewhere and the team’s findings are consistent with previous work—but the more accurate and complete our data, the more likely it is that these discrepancies will be resolved.
There is more work to be done; The results are not certain, yet. Adding more surveys will help improve the map and validate (or flip) the team’s findings.
And, of course, the map itself will help other scientists to conduct their own investigations into the mysterious and mysterious history of the universe.
Research published in physical review d. All three cards are available on the arXiv server and can be found here hereAnd hereAnd here.