The universe’s galaxies grew over billions of years. A new study confirms Einstein’s theory and reveals clues about mysterious particles. Learn more!
Gravity has played a fundamental role in shaping the cosmos. Its attractive force amplified small variations in the early universe’s matter distribution, transforming them into the vast galactic structures we observe today. A new study using data from state-of-the-art Dark Energy Spectroscopic Instrument (DESI) has mapped how nearly 6 million galaxies grew over the past 11 billion years.
DESI can capture light from 5000 galaxies simultaneously. It is mounted on the US National Science Foundation’s Nicholas U. Mayall 4-metre Telescope at Kitt Peak National Observatory. The study is now in its fourth of five years surveying the sky and plans to ‘view’ roughly 40 million galaxies and quasars by the time the project ends. It collaborates with more than 900 researchers from over 70 institutions worldwide, managed by the US Department of Energy’s Lawrence Berkeley National Laboratory. In this new study, the researchers found that gravity behaves as predicted by Einstein’s theory of general relativity.
The study also placed new upper bounds on the mass of neutrinos, the only fundamental particles whose masses remain imprecisely measured. Previous experiments have determined that the combined mass of the three types of neutrinos must be at least 0.059 eV/c² (for context, an electron has a mass of about 511,000 eV/c²). DESI’s findings suggest that the total neutrino mass must be less than 0.071 eV/c², narrowing the neutrino masses range.
“Dark matter makes up about a quarter of the universe, and dark energy makes up another 70%, and we don’t know what either one is,” says Mark Maus, a PhD student at Berkeley Lab and UC Berkeley. “The idea that we can take pictures of the universe and tackle these big, fundamental questions is mind-blowing.”
