Early light coming from the Big Bang has uncovered an accurate new estimate for the age of the Universe: about 13.77 billion years. The new numbers, based on data collected by a network of telescopes located in the Chilean Atacama Desert, also strikes one of the most major disagreements in astrophysics: the velocity of the expansion of the Universe.
Explained in two scientific papers, the new estimate provides a significant boost to one side of the dispute, but the physicists could not prove the other side of the disagreement wrong either.
The Expansion Pace of the Universe
So, here is the issue: researchers need to understand the Universe’s expansion pace to make any sense of cosmology, which is the science of the Universe’s past, present, and future. A portion of the Atacama Cosmology Telescope‘s image of the cosmic microwave background (CMB).
So far, they know that an enigmatic substance called dark energy is making the Universe expand in all directions. However, when astronomers look through the telescopes to measure the Hubble constant (H0) – the number that describes the rate at which the Universe is expanding at various distances from us or another point – they get numbers that disagree with each other, depending on the technique they are using.
“We find an expansion rate that is right on the estimate by the Planck satellite team,” which is another study of the CMB, Cornell University astrophysicist Steve Choi, lead author of one of two new papers, said. “This gives us more confidence in measurements of the universe’s oldest light.”
The data from the Planck satellite, made public in 2018, were the most crucial calculations of the CMB so far. With an unprecedented level of accuracy, they showed how severely CMB measurements of H0 clash with those based on the movement of close galaxies.
The new results remeasured the CMB data from scratch using a completely different set of telescope data and estimates and had a similar outcome. That doesn’t prove that the CMB measurement of H0 this time is correct, as there could still be some issues with the physics theories used to draw the result, but it does suggest that there aren’t any calculation errors on that side of the dispute.
The ‘True‘ Age of the Universe
Based on data from the Atacama Cosmology Telescope (ACT) in Chile’s Atacama Desert, the experts tracked slim differences between various regions of the CMB, which seems to have different energy levels in different parts of the sky.
The CMB is identifiable in every direction in space as a microwave glow, and it is located over 13 billion light-years in the distance, a lot of time before stars and galaxies took shape. By merging theories on how CMB formed with accurate measurements of its fluctuations, researchers can estimate how fast the Universe was expanding at that moment in time. That information can be used to calculate H0.
The new map also provided us with a new measure of the distance between Earth and the CMB. That distance, combined with a new calculation of the pace of Universe’s expansion over time, allowed a precise measurement of the age of the Universe.
“I didn’t have a particular preference for any specific value — it was going to be interesting one way or another,” Choi said.
It is still very feasible that some errors in those theories are messing up the estimate, but it is not clear what the issue would be. For now, the true H0 is still a mystery, but CMB researchers have more bullets for their side of the dispute.
Both new papers detailing the new analysis have been published in the pre-print database arXiv.