Jingyi Zhang/NASA
The speed at which the Universe is expanding has left cosmologists perplexed, as two precise ways of measuring its rate of expansion give very different answers.
The attempt to determine the speed at which the Universe is expanding has “annoyed” cosmologists for decades, leading it to be dubbed the Hubble tension – or even the Hubble tension. Hubble crisis.
But new discoveries, presented in a recently published in the journal Nature Astronomycould help finally answer this cosmic question.
“This is a exciting moment for us and the cosmological community at large, because our idea could solve two major unsolved puzzles about our Universe – the Hubble tension and the origin of cosmic magnetic fields,” Levon Pogosianprofessor and chair of the Physics department at Simon Fraser University, and co-author of the scientific article.
“Solving these puzzles would be like open a new window to the beginning of the Universe. It would help cosmologists to better explain the origin of the Universe and everything in it”, he adds.
The researchers’ theory focuses on primordial magnetic fieldstiny magnetic fields that may have existed since the beginning of time.
Researchers argue that primordial magnetic fields may have accelerated the recombination process – when electrons and protons combine to form atoms – altering the patterns of the cosmic microwave background radiation.
In turn, this would affect how scientists extract value from data. Hubble constantthe unit that describes the speed at which the Universe is currently expanding.
Releasing tension
The Hubble voltage is named after the pioneering astronomer Edwin Hubblewho observed that distant galaxies are all moving away from ours.
Not so much, speed at which the Universe is expanding has left cosmologists perplexedsince two precise ways of measuring its rate of expansion give very different answers.
This discrepancydesignated by Hubble voltageis considered one of the hottest topics in cosmology.
“It’s a big headache for cosmologists around the world. It gave rise to an industry of scientists inventing new ingredients in the cosmological model to try to resolve the Hubble tension,” says Pogosian.
“But what we are saying is that the ingredient, the magnetic fields, could have been there all this time. And, if confirmed, it would also explain the origin of the magnetic fields observed throughout the cosmos.”
Over the past three years, Pogosian’s collaborators Karsten Jedamzik of Montpelier University, Tom Abel of Stanford University and Yacine Ali-Haimoud of New York University have used SFU’s supercomputer to simulate the recombination process in great detail.
The results were then used to analyze data from the Hubble telescope, the Planck satellite and other telescopes to test his theory.
“It is remarkable that our results show that the idea survives the most detailed and realistic tests currently available,” says Pogosian.
“Most importantly, they provide clear targets for future observations. Over the next few years, we will learn whether the tiny magnetic fields of the dawn of time really helped shape the Universe we see today, and whether they hold the key to resolving the Hubble tension once and for all.”
SFU’s Cedar supercomputer, and its successor Fir, played a key role in the team’s research.
“We would not have been able to carry out our research without the supercomputer. It was crucial for our tests and calculations,” says Pogosian.
“The supercomputer allowed us to divide our tests into smaller tasks and run them in parallel, which saved us a lot of time.”
