The largest 3D map of the universe is the result of an analysis of more than four million super-bright and energetic galaxies and quasars. The efforts of hundreds of scientists from around 30 institutions around the world have now borne fruit in what is a “complete history of the expansion of the universe,” in the words of Will Percival of the University of Waterloo in Ontario, Canada. .
Although previous observations had mapped the galaxies (relatively) closest to the Milky Way and looked at the Cosmic Microwave Background (CMB), there was still a gap in the data.
“We know quite well the ancient history of the universe and its recent expansion history, but there is a troublesome gap in the middle of 11 billion years,” team leader Kyle Dawson of the University of Utah said in a statement. “For five years, we have worked to fill that gap, and we are using that information to provide some of the most important advances in cosmology in the last decade.”
The map therefore represents our best understanding so far of the expansion rate of the universe since the Big Bang. The work confirms that the expansion of the universe began to accelerate about 6 billion years ago , becoming faster and faster since then (probably due to dark energy). The expansion rate of the universe is given by a parameter known as the Hubble constant. In this study, the team estimated that the constant has a value of 68 kilometers per second per megaparsec (one megaparsec equals 3.26 million light years). This means that if two galaxies are separated by 1 megaparsec, they would appear to be moving away from each other at a speed of 68 kilometers per second.
As we can see in the video below, the map shows filaments of matter and voids that more precisely define the structure of the universe since its inception, when it was only 380,000 years old.
This is an incredible achievement that we hope, very soon, that many more will come thanks to this new and complete map of the cosmos.
