Dark energy research results: Standard model of cosmology supported by six years of space research, with one big caveat

A six-year study of 669 million galaxies has revealed insights into dark energy, the mysterious phenomenon driving the accelerating expansion of the universe.

This groundbreaking study paints a complex picture of our understanding of the universe, showing that the two major theories of cosmology are both equally compatible with new observations of the expansion of the universe. However, both theories are still insufficient to explain why there are such clumps of matter in the universe, suggesting there is still work to be done.

The Dark Energy Survey (DES) analysis combines four types of data collected by the Victor M. Blanco telescope in Chile, covering about one-eighth of the sky. The study focuses on the past and present expansion of the universe, and imposes about twice as many constraints on models of that expansion as previous studies.

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“These results from the Dark Energy Survey shed new light on our understanding of the universe and its expansion,” Regina Lameika, deputy director of the U.S. Department of Energy’s Office of High Energy Physics, said in a statement. “It shows how a combination of long-term investment in research and multiple types of analysis can provide insight into some of the universe’s greatest mysteries.”

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Dark energy is thought to make up about 70% of the total energy in the universe, but astronomers still know little about its true nature. Scientists proposed this concept to explain observations that suggest the universe is expanding at an ever-accelerating rate. DES is one of several collaborations developed to study the phenomenon in more detail.

In a new paper posted on the preprint server arXiv on January 21, DES scientists investigated the expansion of the universe using four types of markers. Type Ia supernovae are stellar explosions that help scientists measure the distances of objects in the universe. Galaxy cluster. Weak gravitational lensing occurs when a galaxy cluster warps space-time and distorts the apparent shape of objects behind it. A series of 18 supporting papers delves into the findings.

Overall, the data and analysis are consistent with previous research on dark energy, but the new study places tighter constraints on models of how the universe behaves. The data are broadly consistent with the standard model of cosmology, in which the density of dark energy is constant. The data also agreed with a related model in which the dark energy density changes over time, but the agreement was less good than with the standard model.

“Based on all the data, it feels incredible to see results like this for all four of DES’ planned spacecraft,” study co-author Yuanyuan Zhang, an astronomer at the National Science Foundation’s NOIR Lab, which manages the telescope, said in a statement. “This was something we were only brave enough to dream about when DES started collecting data, but now that dream has become a reality.”

Although the fit between the data and the standard model is relatively good, several questions remain. The galaxy clustering patterns still do not match exactly what the standard model predicts, but the differences are not large enough to conclude that the standard model is wrong, the researchers added.

Still, DES researchers plan to continue testing this and other dark energy models in collaboration with Chile’s Vera C. Rubin Observatory to better understand the mysterious phenomenon.

“Rubin’s unprecedented exploration of the southern sky will enable new experiments in gravity and shed light on dark energy,” Chris Davis, NSF program director at NOIRLab, said in a statement.