A new accurate map of everything in the universe has been released

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A team of scientists, consisting of experts from the University of Chicago and the Fermi National Accelerator Laboratory, has declared a game changer by issuing one of the most accurate measurements yet of the distribution of matter in the universe.

The analysis combines Dark Energy Survey and South Pole Telescope data to understand the evolution of the universe.

Sometimes to find out what’s the matter, you have to find it first.

When the universe began, matter rushed outward and gradually formed the planets, stars, and galaxies we know and love today. By carefully compiling a map of this matter today, scientists can try to understand the forces that shaped the evolution of the universe.

A group of scientists, including several from the University of Chicago and the Fermi National Accelerator Laboratory, have released one of the most accurate measurements ever made of how matter is distributed through the universe today.

Combining data from two major telescope surveys of the universe, the Dark Energy Survey and the Antarctic Telescope, the analysis involved more than 150 researchers and was published as a set of three articles Jan. 31 in the journal Physical Review D.

Among other findings, the analysis indicates that matter is not as “lumpy” as we would expect based on our current best model of the universe, adding to the body of evidence that there may be something missing from our current standard model of the universe.

Scientists have released a new survey of all the matter in the universe, using data obtained by the Chile Dark Energy Survey and the Antarctic Telescope. Image source: Photo by Andreas Papadopoulos

Cooling and agglomeration

After the Big Bang created all of the matter in the universe in a few super-hot, intense moments about 13 billion years ago, that matter has been spreading out, cooling and agglomerating over time. Scientists are very interested in tracing the course of this matter; By seeing where it ended up, they could try to recreate what happened and what forces had to be at play.

The first step is to collect massive amounts of data using telescopes.

In this study, scientists combined data from two very different telescope surveys: the Dark Energy Survey, which has surveyed the sky over six years from a mountaintop in Chile, and the Antarctic Telescope, which looks for faint traces of radiation still traveling. across the sky from the very first moments of the universe.

The South Pole Telescope is part of a collaboration between Argonne and a number of national laboratories and universities to measure the CMB, which is the oldest light in the universe. The high altitude and extremely dry conditions in the Antarctic keep water vapor from absorbing specific wavelengths of light. Credit: Image courtesy of Argonne National Laboratory

Combining two different ways of looking at the sky reduces the likelihood that results will be invalidated by an error in some form of measurement. “It works like a cross-scan, so it becomes a much more robust measurement than if you used one or the other,” said University of Chicago astrophysicist Shihuai Zhang, one of the studies’ lead authors.

Either way, the analysis looked at a phenomenon called gravitational lensing. As light travels through the universe, it can be bent slightly as it passes gravitationally bound objects, such as galaxies.

This method captures both ordinary matter and dark matter – the mysterious form of matter that we’ve detected only because of its effect on ordinary matter – because both normal matter and dark matter exert gravity.

By carefully analyzing these two sets of data, scientists can infer where all the matter in the universe ended up. The authors said it’s more accurate than previous measurements — that is, it narrows the odds of ending the question — than previous analyses.

By overlaying maps of the sky from the Dark Energy Survey Telescope (left) and the Antarctic Telescope (right), the team can piece together a map of how matter is distributed, which is critical to understanding the forces that shape the universe. Credit: Photo courtesy of Yuki Ohori

The majority of the results are completely consistent with the currently best accepted theory of the universe.

But there are also signs of a rift—suggested in the past by other analyzes as well.

“There appears to be slightly less fluctuations in the present-day universe than we would expect assuming our standard cosmological model associated with the early universe,” said Eric Baxter, one of the authors of the analysis and an astrophysicist at the University of Hawaii (UChicago PhD’14).

That is, if you make a model that includes all currently accepted laws of physics, then take the readings from the beginning of the universe and extrapolate them forward through time, the results look a little different than what we’re actually measuring around us today.

“There are so many new things you can do when you combine these different angles of looking at the universe.”

– Chihuai Zhang, an astrophysicist at the University of Chicago

Specifically, today’s readings found that the universe is less “clumpy”—clumping up in certain regions rather than evenly spread out—than the model predicts.

Scientists say that if other studies continue to find the same results, it could mean that something is missing in our current model of the universe, but the results have not yet reached the statistical level that scientists consider rigorous. This will require further study.

However, the analysis is a milestone because it provided useful information from two very different telescope surveys. This is a very expected strategy for the future of astrophysics, as more large telescopes come online in the coming decades, but few have actually been implemented so far.

“I think this exercise demonstrated both the challenges and the benefits of doing these types of analyses,” Zhang said. “There are so many new things you can do when you combine these different angles of looking at the universe.”

University of Chicago Kavli Associate Fellow Yuki Omori was also a co-lead author of the papers. The full studies and literature, “Joint Analysis of Third-Year Dark Energy Survey Data and the CMB Effect from SPT and Planck” can be found in three papers selected as an Editor’s Suggestion in Physical Review D.

References:

“Joint analysis of third-year Dark Energy Survey and CMB effect data from SPT and Planck. I. Creation of CMB lens maps and modeling options” by Y. Omori et al. (DES and SPT Collaborations), Jan 31, 2023, Physical Revision D.DOI: 10.1103/PhysRevD.107.023529

“Joint Analysis of Third-Year Dark Energy Survey and CMB Effect Data from SPT and Planck. II. Measurements of Cross-Correlation and Cosmological Constraints” by C. Chang et al. (DES & SPT Collaborations), Jan. 31, 2023 Physical Review D.DOI: 10.1103/PhysRevD.107.023530

“Joint analysis of third-year Dark Energy Survey and CMB effect data from SPT and Planck. III. Collected cosmological constraints” by T.MC Abbott et al. (DES and SPT Collaborations), Jan. 31, 2023, Physical Revision D.DOI: 10.1103/PhysRevD.107.023531

The South Pole Telescope is funded primarily by the National Science Foundation and the Department of Energy and operated through a collaboration led by the University of Chicago. The Dark Energy Survey was an international collaboration coordinated by the Fermi National Accelerator Laboratory and funded by the Department of Energy, the National Science Foundation, and many institutions around the world.

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