astronomer using dark energy spectrometer The most advanced instrument (DESI) aboard NSF's Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory maps how nearly 6 million galaxies cluster together over 11 billion years of the universe's history I did. Their results provide one of the most rigorous tests of Albert Einstein's theory of general relativity to date.
This artist's impression shows the evolution of the universe, starting with the Big Bang on the left and continuing with the emergence of the Cosmic Microwave Background. The formation of the first stars ends the Dark Ages of the universe, followed by the formation of galaxies. Image credit: M. Weiss / Harvard-Smithsonian Center for Astrophysics.
“General relativity has been very well tested at the scale of the solar system, but we also needed to test whether our assumptions work on even larger scales,” said the CNRS and Institute for Nuclear and High Energy Research. said cosmologist Dr. Pauline Zarouk. Physics.
“Studying the rate of galaxy formation allows us to directly test our theory, and so far it is consistent with what general relativity predicts on cosmological scales.”
In a new study, Dr. Zarouk and his colleagues found that gravity behaves as predicted by Einstein's theory of general relativity.
This result validates our main model of the universe and limits the possibility of a modified theory of gravity. Modified gravity theories have been proposed as an alternative way to explain unexpected observations, such as the accelerated expansion of the universe, which is usually attributed to dark energy.
This complex analysis uses around 6 million galaxies and quasars, allowing researchers to look up to 11 billion years into the past.
Today's results provide an expanded analysis of DESI's first year of data. DESI created the largest 3D map of the universe to date in April, revealing hints that dark energy may be evolving over time.
April's results examine a particular feature of how galaxies cluster together, known as baryon acoustic oscillations (BAOs).
The new analysis expands the scope by measuring how galaxies and matter are distributed across the universe at different scales.
The study also improved constraints on the mass of neutrinos, the only fundamental particle whose mass has not yet been precisely measured.
Neutrinos slightly affect the clustering pattern of galaxies, which can be measured by the quality of the DESI data.
The DESI constraints are the most stringent to date and complement those from laboratory measurements.
The study required months of additional work and cross-checking. As with the previous study, they used a method that kept the results of the study hidden from the scientists until the end, reducing unconscious bias.
“This research is one of the important projects of the DESI experiment to learn not only fundamental aspects of particles, but also fundamental aspects of the large-scale universe, such as the distribution of matter and the behavior of dark energy.” he said. Dr. Stephanie Juneau is an astronomer in NSF's NOIRLab and a member of the DESI Collaboration.
“By comparing the evolution of the distribution of matter in the universe with existing predictions, such as Einstein's theory of general relativity and competing theories, we are further narrowing down the possibilities for the gravitational model.”
“Dark matter makes up about a quarter of the universe, and dark energy makes up another 70%, but we don't actually know what either is,” says Dr. Mark Maus. student at Berkeley Lab and the University of California, Berkeley.
“The idea that we can take pictures of the universe and address these big fundamental questions is amazing.”
The DESI Collaboration today shared its results below. some papers in arXiv.org.
Source: www.sci.news
