The expansion of the universe may be a mirage, a potentially controversial new study suggests.
This rethinking of the universe also suggests solutions to the puzzles of dark energy and dark matter, which scientists believe make up about 95% of the universe’s total energy and matter but remain shrouded in mystery.
The novel new approach is described in an article published June 2 in the journal Classical and Quantum Gravity, by University of Geneva professor of theoretical physics Lucas Lombriser.
Connected: Our Expanding Universe: Age, History, and Other Facts
Scientists know that the universe is expanding due to redshift, the stretching of light toward the redder end of the spectrum as the object emitting it moves away from us. Distant galaxies have higher redshifts than those closer to us, indicating that they are moving further and further away from Earth.
Recently, scientists have found evidence that the expansion of the universe is not static, but is actually accelerating faster and faster. This rapid expansion is captured by a term called the cosmological constant or lambda.
The cosmological constant has been a headache for cosmologists because predictions of its value made by particle physics differ from actual observations by 120 orders of magnitude. The cosmological constant has therefore been described as “the worst prediction in the history of physics.”
Cosmologists often try to resolve the discrepancy between different values of lambda by postulating new particles or physical forces, but Lombriser tackles it by reimagining what already exists.
“In this work, we put on new glasses to view the universe and its unsolved puzzles by performing a mathematical transformation of the physical laws that govern it,” Lombriser told Live Science via email.
In Lombriser’s mathematical interpretation, the universe is not expanding, but is flat and stationary, as Einstein once believed. The effects we see that point to expansion are instead explained by the evolution of the mass of particles – such as protons and electrons – over time.
In this picture, these particles emerge from a field that permeates space-time. The cosmological constant is set by the mass of the field, and because this field fluctuates, the mass of the particles it feeds also fluctuates. The cosmological constant still varies with time, but in this model this variation is due to changing particle masses over time, not the expansion of the universe.
In the model, these field fluctuations result in higher redshifts for distant galaxy clusters than traditional cosmological models predict. And so the cosmological constant remains faithful to the model’s predictions.
“I was surprised that the cosmological constant problem seems to simply disappear in this new perspective on the universe,” Lombriser said.
Recipe for the dark universe
Lombriser’s new framework also addresses some of cosmology’s other pressing problems, including the nature of dark matter. This invisible substance outnumbers ordinary matter particles by a ratio of 5 to 1, but remains mysterious because it does not interact with light.
Lombriser suggested that fluctuations in the field could also behave like a so-called axion field, since axions are hypothetical particles that are one of the suggested candidates for dark matter.
These fluctuations could also dissipate dark energy, the hypothetical force that stretches the matter of space, thus driving galaxies apart faster and faster. In this model, according to Lombriser, the effect of dark energy would be explained by the fact that particle masses take a different evolutionary path at later times in the universe.
In this picture, “there’s basically no need for dark energy,” Lombriser added.
Luz Angela Garcia, a postdoctoral researcher at ECCI University in Bogota, Colombia, was impressed by Lombriser’s new interpretation and how many problems it solves.
“The paper is quite interesting and it gives an unusual result for many problems in cosmology,” García, who was not involved in the study, told Live Science. “The theory provides an outlet for current tensions in cosmology.”
García, however, urged caution in evaluating the paper’s findings, saying it contains elements of its theoretical model that likely cannot be tested observationally, at least in the near future.
Originally published on LiveScience.com.
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