Universe expansion may be an illusion, study points out – DW – 07/03/2023

The expansion of the universe could be an illusion, according to a study recently published in the scientific journal Classical and quantum gravity.

Such an innovative approach could also shed light on the puzzles of dark energy and dark matter, which scientists say make up around 95% of the total energy and matter in the universe.

The new approach was presented by professor of theoretical physics Lucas Lombriser, from the University of Geneva, in a paper published in June.

Expansion of the universe and cosmological constant

According to the science news portal live science, scientists know that the universe is expanding due to what is known as redshift, which is an increase in the wavelength of light toward the farther end. red of the spectrum when the object emitting light moves away from us. Distant galaxies have a greater redshift than those closer to Earth, suggesting that they are moving further and further away from our planet.

Recently, scientists have discovered that the expansion of the universe is not constant, but is accelerating more and more. This acceleration is attributed to the so-called cosmological constant or lambda. However, ever since Albert Einstein described such a constant over 100 years ago, it has been a challenge for cosmologists, as theoretical predictions differ greatly from actual observations, leading them to come up with new particles or forces to explain such a gap. .

New hypothesis on the accelerated expansion of the universe

Rather than proposing new particles or physical forces, Lombriser proposes to rethink what is already known. In an interview with live science About his new study, the astrophysicist said his new hypothesis involves a new look at the long-established theory of the accelerating expansion of the universe.

“In this work, we put on a new pair of glasses to observe the cosmos and its undeciphered enigmas, performing a mathematical transformation of the physical laws that govern it,” Lombriser said.

“I was surprised that the problem of the cosmological constant seemed to disappear in this new perspective on the cosmos.”

flat and static universe

In Lombriser’s mathematical interpretation, the universe is not expanding but flat and static, as originally proposed by Albert Einstein, before the introduction of the idea of ​​the cosmological constant. According to the astrophysicist, the effects that we have observed that point to an expansion are explained by the evolution of the mass of particles, such as protons and electrons, over time.

In this scenario, these particles come from a field that permeates spacetime. The cosmological constant is defined by the mass of the field, and as this field fluctuates, the masses of the particles it generates also fluctuate. The cosmological constant still varies with time, but in this model that variation is due to the changing mass of particles over time, not the expansion of the universe.

Regarding dark matter, which cannot be directly observed, Lombriser’s study suggests that this mysterious material could behave like an axion field, a hypothetical particle considered to be one of the main candidates to explain dark matter.

What’s more, fluctuations in this field could mean that dark energy, the mysterious force responsible for the accelerated separation of galaxies, is not needed, Lombriser told the live science.

Promising approach, but difficult to verify

Although the proposed approach may hold promise for addressing the challenges associated with the cosmological constant, physicist Luz Ángela García, a researcher at ECCI University in Bogotá, cautions that caution is advised when evaluating the findings of the cosmological constant. ‘article.

At live scienceshe said the new theoretical model contains elements that are unlikely to be verified by observation, at least not in the near future.

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