Astronomers have unveiled the biggest-ever 3D map of our universe, after analysing 4 million galaxies.
The 20-year project could shed new light on how our universe expanded – and fill in a huge “gap” in our history of the universe, the scientists said.
The history of the early universe is thought to be fairly well known, due to theoretical models of the time after the Big Bang and observation of the Cosmic Microwave Backgound Radiation (CMBR).
But until now, there has been a gap of around 11bn years in our history of the universe.
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Cosmologist Kyle Dawson of the University of Utah said, “We know both the ancient history of the universe and its recent expansion history fairly well, but there’s a troublesome gap in the middle 11 billion years.
“Thanks to five years of continuous observations, we have worked to fill in that gap, and we are using that information to provide some of the most substantial advances in cosmology in the last decade.”
The “map” is the result of 20 years of work by several hundred scientists from around 30 different institutions.
The scientists all worked with the Sloan Digital Sky Survey (SDSS), with data collected from an optical telescope dedicated to the project located in New Mexico, in the United States.
The study analysed millions of galaxies and energetic quasars, via an astronomical survey from 2014 until 2020.
“We have now provided the most accurate expansion history measurements over the widest-ever range of cosmic time,” says Will Percival of the University of Waterloo, survey scientist at the extended Baryon Oscillation Spectroscopic Survey (eBOSS),
“These studies allow us to connect all these measurements into a complete story of the expansion of the universe.”
The map shows filaments of matter and voids that more precisely define the structure of the universe since its beginnings, when it was only 380,000 years old.
From there, the researchers measured the recurring patterns in the distribution of galaxies, thus identifying several key cosmological parameters, including the density of hypothetical dark matter and energy in the Universe, with a high degree of precision.
Teams involved in the eBOSS project looked at different galactic tracers that reveal the mass distribution in the Universe.
For the part of the map relating to the universe 6bn years ago, researchers observed the oldest and reddest galaxies.
For more distant eras, they concentrated on the youngest galaxies, the blue ones. To go back further, that is to say up to 11bn years, they used quasars, galaxies whose super-massive black hole is extremely luminous.