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Paris (AFP)
Scientists in France looked at the early universe twelve billion years ago and saw the light bulbs of hydrogen gas, known as the ‘cosmic web’, they said on Thursday.
Cosmological models have long predicted its existence, but until now the cosmic web has never been directly observed and captured in images.
Eight months of observation with the Very Large Telescope of the European Southern Observatory and a year of data shrinkage revealed the filaments as they existed only one to two billion years after the big bang.
But the biggest surprise, according to scientists, were simulations showing that the light came from billions of previously invisible – and unsuspecting – dwarf systems that spawned trillions of stars.
The findings were reported in the journal Astronomy & Astrophysics.
“After an initial period of darkness, the universe erupted with light and produced a large number of stars,” senior author Roland Bacon, a scientist at the Center for Astrophysics Research in Lyon, told AFP.
“One of the great questions is what ended the period of darkness. This led to a phase in the early Universe known as re-ionization.
Until now, astronomers have obtained only partial and indirect views of the cosmic web through quasars, whose powerful radiation, such as car lights, reveal gas clouds along the line of sight.
But these regions do not represent the entire network of filaments where most galaxies – including our own – were born.
Plumbing new depths –
“These findings are fundamental,” said Emanuele Daddi, a researcher at the Atomic Energy Commission who did not participate in the study.
“We have never seen a gas discharge on this scale, which is essential to understanding how galaxies form.”
The team trained the ESO’s Very Large Telescope – equipped with a 3D spectrograph called MUSE – for more than 140 hours in a single airspace.
Together, the two instruments form one of the most powerful observation systems in the world.
The selected region is part of the Hubble Ultra-Deep Field, which includes the deepest image of the cosmos ever obtained.
But the new images make new depths of the early universe a darkness – 40 percent of the newly discovered galaxies were beyond Hubble’s reach.
Although these galaxies – 10 to 12 billion light-years away – are too faint to be detected individually with current instruments, their existence is likely to strengthen and challenge existing models of galaxy formation.
Scientists are only now beginning to investigate its implications, the researchers said.
Astronomers at the Lagrange Laboratory for the University of Cote d’Azur contributed to the research.
© 2021 AFP