Our grasp of the universe is evolving.
Cosmologists have discovered signs of a new kind of dark energy that might have come into being during the initial 300,000 years following the Big Bang, according to a report from the peer-reviewed journal Nature citing two separate studies published in the last week.
And, if it's there, cosmologists may soon confirm a really strong signal.
Early dark energy might be found via a 'strong signal' in the Big Bang's afterglow
Both studies revealed the detection of what might be the first traces of this mysterious "early dark energy" present in data gathered from 2013 to 2016 by the Chile-based Atacama Cosmology Telescope (ACT). While the findings are as of writing only at the preprint stage and require peer review for confirmation, they might solve a long-standing paradox about the early universe and data collected surrounding it that seems incompatible with the rate of cosmic expansions witnessed today. But sadly, the new data is only preliminary, and doesn't conclusively prove that this new type of dark energy was ever really there. "There are a number of reasons to be careful to take this as a discovery of new physics," said Cosmologist Silvia Galli at the Paris Institute of Astrophysics.
One of the preprints was shared by the ACT team of researchers, and the other one came from an independent group, but they both concede that the new data has yet to reach a level of certainty to assure the existence of early dark energy with scientific confidence. But this could be remedied with further observations from the ACT, in addition to another observatory, the South Pole Telescope (based in Antarctica), which might offer a more thorough test. "If this really is true — if the early universe really did feature early dark energy — then we should see a strong signal," said a co-author of the ACT paper named Colin Hill, who's a Columbia University cosmologist based in New York City. The South Pole Telescope and the ACT are both capable of mapping the cosmic microwave background (CMB), which is primordial radiation that's sometimes metaphorically described as the Big Bang's afterglow.
Early dark energy could alter the way we view the universe's evolution
The CMB represents one of the core windows for cosmologists to peer into the early universe, which is why mapping subtle variations in this primitive "afterglow" has helped scientists build a compelling case for the "standard model of cosmology". This is a model that purports to explain the evolution of the universe via three main elements: dark energy, dark matter, which is similarly mysterious and thought to have guided the formation of the galaxies, and the conventional matter of our sensible world, which only accounts for less than 5% of the entire energy and mass of the cosmos.
Early dark energy, if it's real, wouldn't have possessed the strength to cause accelerated expansion of the universe. Not in the way "typical" dark energy does. But early dark energy surely would have forced the plasma that emerged from the Big Bang to cool more rapidly than it would have without it. And this, in turn, would modify the way scientists need to interpret CMB, especially on the subject of measuring the age of the universe via the distance sound waves could travel through the primordial plasma of the Big Bang, before it cooled into a gas. There's much left to learn about the universe, and its origins, and the new pair of studies are only the latest testament to this fact.