They publish a new map of how matter is distributed in the universe

They publish a new map of how matter is distributed in the universe

View of space near the Dark Energy Chamber, in Chile. / Andreas Papadopoulos

Science | Space

The analysis is the most precise, to date, and has had the participation of 150 researchers, including several Spanish scientists

Elena Martin Lopez

The Big Bang ejected all the matter we know today from the universe 13 billion years ago, and since then it has gradually expanded, cooled, and agglomerated, giving rise to the galaxies, stars, and planets we know today. For researchers, tracing the path that this matter has followed from its origin to the present is very important to better understand the formation and evolution of the universe. Along these lines, a team of 150 researchers, including several Spanish scientists, has presented a new map, with the most precise measurements to date, of how matter is distributed in the universe. Their results have been published, this Tuesday, as a set of three articles in the journal 'Physical Review D'.

How has it been done?

This study is part of a larger project that combines data from two important instruments: the Dark Energy Chamber, in Chile, from which updated data has been collected from its last three years of observations; and the South Pole Telescope, built specifically for this project to locate the faint traces of radiation that are still traveling across the sky from the Big Bang.

"Previously, we carried out a similar analysis with older data and we could not achieve precise measurements of the parameters that describe our universe," astrophysicist Chihway Chang, from the University of Chicago, and one of the main authors of the studies, explained to this newspaper. studies. "Correlating multiple data sets makes us less susceptible to errors, because it's much harder for two separate data sets to be wrong in the same way," she added.

What does the study consist of?

To draw the map the researchers have used a technique called gravitational lensing. Just as when we look through the curved base of a glass bottle we see the image distorted and magnified, a gravitational lens distorts and magnifies the image of distant bright objects when its light encounters a massive object containing gravity, such as a galaxy. , and curves around it. Thus, when our telescopes receive that light, we can see these distant objects amplified. This method captures both regular matter and dark matter, because both exert gravity.

In this study, the light source used has been that which comes from cosmic microwave radiation (CMD), a form of electromagnetic radiation that fills the entire universe, which has allowed all matter to be mapped existing.

What has been the biggest challenge?

Observations of the cosmic microwave background (CMB) can be contaminated by various sources, such as galactic dust, which skews the results. “Removing these foreground contaminants from the analysis has been one of the most significant advances in this work over previous ones,” Chung says.

What has been discovered?

By rigorously analyzing the data sets provided by both telescopes, the scientists wanted to know how matter has been distributed in the universe since the Big Bang. One of the findings indicates that matter does not clump together as much as previous maps of the universe showed.

In addition, they have shown that the results obtained by correlating data from both telescopes are consistent with those obtained by the Chilean telescope individually, "which is not a trivial statement given the complexity of the analyses," Chung stated. "This is an important step forward in the field of multi-database joint cosmology analyses."

What are your conclusions?

Most of the results fit perfectly with the currently accepted best theory of the universe, but also show small discrepancies that have been suggested in the past by other analyses. Specifically, scientists have observed that the universe is less 'lumpy', that is, matter accumulates less than the existing model of the universe predicts. If other studies continue to find the same results, the researchers say, it may mean something is missing from our model, "but much more research is needed on this, so we think this model is still consistent," Chang adds.