Scientists have used models to explore the early days of the universe some 12 billion years ago, seeing for the first Time a “cosmic web” of dense, shiny threads of hydrogen gas; not only that, they have also found that the bright light of the web comes from billions of previously unobserved dwarf galaxies.
AFP and CNN reported today that scientists have long inferred the existence of a “cosmic web” through models of the universe, but have never directly observed or captured images of it before. Most galaxies, including the one we are in, were born on a “cosmic web.
These shiny filaments existed only a billion to two billion years after the Big Bang, and now, with eight months of observations from the European Southern Observatory’s Very Large Telescope (VLT) Plus up to a year of data processing, the “cosmic network” has finally appeared.
But the biggest surprise, scientists say, is not the discovery of the “cosmic web” itself, but the simulation shows that the bright light of the “cosmic web” comes from billions of previously invisible, undiscovered dwarf galaxies.
The results of the study were published in the journal Astronomy & Astrophysics.
“After an initial period of darkness, the universe bursts into light and makes a lot of stars,” Roland Bacon, a scientist at the Centre for Astrophysics Research in Lyon, France, told AFP. “The question is, what ended that darkness” and sent the early universe into what is known as “reionisation”.
Astronomers have previously only been able to observe the local aspects of the cosmic web indirectly through quasars. The powerful radiation from quasars acts like the headlights of a car, illuminating the gas clouds along the line of light.
But those blocks are not the full picture of the cosmic network.
The team targeted a block of the sky with the 3D spectrograph MUSE for more than 140 hours, and part of the block was covered by the Hubble Ultra Deep Field (HUDF), a photograph of outer space. But the combination of MUSE and the Very Large Telescope has produced one of the most powerful observing systems in the world, with new images that probe new depths in the early universe and new discoveries of galaxies that exceed the Hubble range by 40 percent.
The light from these galaxies is too faint to be detected independently by today’s equipment, but discovering their existence could enhance and challenge existing models of galaxy formation.
Emanuele Daddi, a researcher at the French Atomic Energy Commission (Atomic Energy Commission), commented, “This discovery is very significant, we have never seen an exhaust of this magnitude, and it is very important for our understanding of galaxy formation.”
The Atomic Energy Commission was not involved in the study.
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