“That work simply gives us the story of the most complete expansion of the Universe to date,” said Will Percival, one of the researchers involved in the University of Waterloo project.
The map, the result of a collaboration of more than 20 years of some hundreds of scientists from thirty different institutions, was prepared from the latest exploration of the SDSS (Sloan Digital Sky Survey, Celeste Sloan Digital Exploration, by the name of the foundation that financed it).
Thanks to the theoretical works on the Big Bang, as well as the observation of the cosmological diffuse background (the residual microwave radiation left by the Big Bang), the first moments of the Universe are relatively well known to researchers.
Studies of galaxies and distance measurements gave a good understanding of the expansion of the Universe that has occurred during the almost 14 billion years of its existence.
“Some data was pending between the beginning of the Universe and the current period,” said Kyle Dawson of the University of Utah and one of the project leaders.
Expansion of the Universe
“In 2012, I launched the project with the idea of producing the most complete map of the Universe in three dimensions, using for the first time as markers the galaxies that still produce stars and quasars,” said Jean-Paul Kneib, astrophysicist at the Polytechnic School. Federal of Lausanne (EPFL).
The map shows strands of matter and voids that define the structure of the Universe since it became transparent to light, when only 380,000 years had passed since the Big Bang.
Regarding the part of the map related to the Universe located 6,000 million light years away, the researchers observed the oldest and reddest galaxies. For the farthest, they concentrated on the youngest galaxies, the blue ones.
To go even further, that is, up to 11,000 million light-years away, they used quasars, the supermassive black holes located in the center of many galaxies and which are the most luminous objects due to the amount of energy they radiate when matter that surrounds them falls inside.
The map shows that at a certain point the expansion of the Universe accelerated and then kept pace. Astrophysical theory calls that period “the great inflation.”
“This acceleration seems to be due to the presence of dark energy, a theoretical element never detected, which is integrated into Einstein’s general theory of relativity, but whose origin is not yet understood,” said the Federal Polytechnic School of Lausanne (EPFL), in Switzerland, who worked on the project.
Astrophysicists have known for decades that the Universe is expanding, and it was the American astronomer Edwin Hubble who discovered the constant of that acceleration in the first half of the 20th century.
However, the most recent studies – including those in this work – confirm that the “Hubble constant” would be 10% lower than the observed value. Difference that scientists attribute to dark energy.
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