A physicist from the University of Texas at Dallas, alongside an international team of researchers in the Dark Energy Spectroscopic Instrument (DESI) collaboration, is conducting a multiyear mission to tackle one of astrophysics’ biggest mysteries: Why is the universe’s expansion accelerating?
Scientists have proposed competing theories to explain this phenomenon. One theory suggests that dark energy, an unknown force, is driving galaxies apart. Another theory posits that gravity—the force that binds objects together in local systems like our solar system—behaves differently on vast cosmic scales and may need to be revised to account for the accelerating expansion.
The DESI collaboration, involving over 900 scientists from more than 70 institutions, has released a new analysis addressing the second theory. Their findings indicate that the clustering of galaxies aligns with the standard model of gravity: Albert Einstein’s general theory of relativity, which also explains how objects fall under gravity and how planets orbit stars.
The analysis provides the most precise test to date of how gravity behaves at very large scales by tracing how cosmic structure grew over the past 11 billion years.
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