Our universe may be twice as old as current estimates, according to new research from the University of Ottawa.
Challenging the dominant cosmological models and solving the 'impossible early galaxy' problem without requiring the existence of primordial black hole seeds, massive Population III stars, etc.
"Our newly-built model extends the formation time of the Milky Way by several billion years, making the universe 26.7 billion years old, not 13.7 billion years as previously estimated" Professor Rajendra Gupta at the University of Ottawa, said.
For years, astrophysicists have estimated the age of the universe by measuring the time elapsed since the Big Bang and studying the oldest stars based on the redshift of light coming from distant galaxies.
In 2021, current age of the Universe was thus estimated at 13.797 billion years using the Lambda-CDM concordance model.
However, many researchers are puzzled by the existence of ancient stars like the Methuselah that appear to be older than the estimated age of the universe and have been made possible by the Webb Telescope discovery of early galaxies in an advanced state of evolution.
These galaxies, which existed about 300 million years after the Big Bang, have a level of maturity and mass typically associated with billions of years of evolution. Plus, they're surprisingly small in size, which adds another layer of mystery to the equation.
Fritz Zwicky's tired light theory proposes that the redshift of light from distant galaxies is due to the gradual loss of energy by photons over enormous cosmic distances. However, this was found to be contradictory with the observations.
Yet, Professor Gupta found that allowing this theory to co-exist with the expanding universe, makes it possible to reinterpret the redshift as a hybrid phenomenon rather than as an expansion outright.
In addition to Zwicky’s tired light theory, he introduces the idea of evolving coupling constants, as hypothesized by Paul Dirac.
Coupling constants are fundamental physical constants that govern the interactions between particles.
According to Dirac, these constants can vary with time.
By allowing them to grow, the timescale for the formation of early galaxies observed by James Webb at high redshift can be extended from a few hundred million years to several billion years.
This provides a more viable explanation for the elevated levels of evolution and mass observed in these earliest galaxies.
Professor Gupta suggests that the traditional interpretation of the cosmological constant, which represents the dark energy responsible for the accelerating expansion of the universe, needs revision.
Instead, he proposes a constant that accounts for the evolution of the coupling constant.
"This modification to the cosmological model helps to solve the puzzle of the size of the smallest galaxies observed in the early universe, allowing for more precise observations," Professor Gupta said.
The research paper was published in Monthly Notices of the Royal Astronomical Society.
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