An international consortium has compiled the most comprehensive 3D map of the observable cosmos to date, significantly improving our understanding of cosmological history while posing new questions about the fundamental laws that govern the universe.
The updated map, compiled from data collected by the Sloan Digital Sky Survey (SDSS), provides a detailed history of the cosmos, from the Big Bang and its initial phase of expansion to the current era.
The latest phase of the project, called the “Extended Baryon Oscillation Spectroscopic Survey” (eBOSS), includes the positions and distances of more than 4 million ultra-bright galaxies and quasars surrounding supermassive black holes, according yet press release from EPFL, a Swiss research institute. The new results aree showing how the universe evolved over a period of 11 billion years, filling a major gap in our knowledge.
“In 2012, I launched the eBOSS project with the idea of producing the most complete 3D map of the Universe throughout the life of the Universe, implementing for the first time celestial objects that indicate the distribution of matter in the distant Universe, the galaxies. actively forming stars and quasars “ Jean-Paul Kneib, co-leader of the project and EPFL astrophysicist, said in the press release. “It is a great pleasure to see the completion of this work today.”
The eBOSS project has resulted in 23 new scientific papers (plus the new map), which were released today to the arXiv prepress server.
Astrophysicists have previously chronicle of the first days of the universe calculated The abundance of elements created after the Big Bang and studying cosmic microwave background radiation“The chilled remnant of the first light of the universe.” Scientists also have a good grasp of recent cosmological history, as reported by galactic maps and distance measurements. But “there is a problematic gap in the middle of 11 billion years,” said Kyle Dawson, cosmologist at the University of Utah and the eBoss principal investigator, in an SDSS Press release.
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To look back at this 11-billion years gap, scientists focused on galaxies and quasars, looking for patterns in how they are distributed throughout the universe. These observations they were then combined with data collected during the previous phases of SDSS, dating Back to 1998.
“Taken together, detailed analyzes of the eBOSS map and previous SDSS experiments have now provided the most accurate expansion history measurements in the widest range of cosmic time.” Will Percival, astrophysicist at the University of Waterloo and eBOSSScientific Survey said in the EPFL statement. “These studies allow us to connect all of these measurements into a complete history of the expansion of the Universe.”
The updated map shows empty voids and filaments that defined the universe just 300,000 years after the Big Bang, which happened 13.8 billion years ago. By identifying ancient quasars (extremely bright galactic nuclei surrounding supermassive black holes)The researchers were able to map regions over 11 billion years old. To map more recent periods, i.e. regions between 6 billion and At 11 billion years old, scientists tracked patterns in the distribution of galaxies, which later allowed for more precise measurements of dark energy.
“One of the things we want to learn is the time evolution of dark energy, this mysterious thing that is causing the universe to speed up,” Ashley Ross, project scientist and researcher at Ohio State University, saying Ohio State News.
According to the new data, the universe entered its acceleration expansion phase about 6 billion years ago, and has accelerated since then.
Interestingly, the new data from eBOSS is complicating our understanding of the rate at which the universe expands, known as the Hubble constant. There appears to be a discrepancy between the local (i.e. recent) rate of universal expansion compared to the early universe, which differs by up to 10%. This 10% difference is “unlikely to be random due to the high precision and wide variety of data in the eBOSS database,” according to the EPFL.
It is not immediately clear why there should be a difference in the rate of expansion between the local and early universe, but it could have something to do with an unknown form of energy or matter that existed at the time.
This now represents a tantalizing possibility that will have to be explored for future research. This may be the most complete picture of the universe to date, but it is another reminder of how much remains to be known.
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