The Dark Energy Survey collaboration announced it has created the largest-ever maps of the distribution and shapes of galaxies, tracing both ordinary and dark matter in the universe out to a distance of more than 7 billion light-years.
The analysis, which includes the first three years of data from the survey, is consistent with predictions from the current best model of the universe. Nevertheless, there remain hints from the Dark Energy Survey and other experiments that matter in the current universe is a few percent less “clumpy” than predicted.
The Dark Energy Survey, an international collaboration coordinated through the University of Chicago-affiliated Fermi National Accelerator Laboratory, surveyed almost one-eighth of the entire sky over six years, cataloguing hundreds of millions of objects. The new results announced May 27 draw on data from the first three years to create the most precise maps yet of the distribution of galaxies in the universe at relatively recent epochs.
Since the Dark Energy Survey studied nearby galaxies as well as those billions of light-years away, its maps provide both a snapshot of the current large-scale structure of the universe and a “movie” of how that structure has evolved over the course of the past 7 billion years.
“We’re trying to understand the universe as a whole, so you need that kind of large-scale dataset,” said Judit Prat, a postdoctoral researcher with the University of Chicago who analyzed weak gravitational lensing as captured by the Dark Energy Survey.
According to our best understanding, ordinary matter makes up only about 5% of the universe. Dark energy accounts for about 70%. The last 25% is dark matter, whose gravitational influence binds galaxies together. Both dark matter and dark energy remain invisible and mysterious, but the Dark Energy Survey seeks to illuminate their natures by studying how the competition between them shapes the large-scale structure of the universe over cosmic time.