Astronomers have made an intriguing discovery that could upend everything we know about the structure of the universe and its expansion.
Scientists recently found that dark energy, the mysterious form driving the accelerating expansion of the universe, could be weakening over time.
The findings could undermine the existing standard cosmological model of the universe called the lambda-cold dark matter (LCDM) model, which takes dark energy, ordinary matter, and cold dark matter — a hypothetical form of dark matter that moves slowly compared to the speed of light — into consideration.
The symbol lambda in the model refers to Albert Einstein’s cosmological constant, which assumes that the universe is accelerating at a fixed rate.
Yet, last year, scientists concluded that dark energy isn’t a constant after all, analyzing observations by the Dark Energy Spectroscopic Instrument (DESI) in Arizona, as New Scientist reports. They found that the mysterious force could be evolving and weakening over time.
In March, scientists released a follow-up, strengthening the unusual findings.
“This is exciting – it might actually be putting the standard model of cosmology in danger,” Autonomous University of Madrid assistant research professor Yashar Akrami told New Scientist.
Instead of making changes to the LCDM itself, Akrami and his colleagues suggested redefining dark energy as a “quintessence field,” which has been used to explain observations of an accelerating rate of expansion of the universe.
That could allow scientists to harmonize more advanced string theory with the standard cosmological model.
“If you prove that quintessence is dark energy, it’s very good for [string theorists],” Akrami told New Scientist. “That’s why the string theory community is really excited now.”
An altered take on the quintessence model of dark energy suggests the mysterious force could be interacting with gravity itself.
“We’ve always grown up thinking about the universe as having the gravitational force, and gravity fuels everything,” University of Oxford astrophysicist Pedro Ferreira told the publication. “But now there’s going to be an additional fifth force, which is due to the dark energy, which also fuels everything.”
But before we can add this fifth force, we’d have to reconcile the fact that we simply haven’t seen any evidence for it, at least not when we’re making precise measurements of our neighborhood of the universe.
“Physics ends up being even more complicated than we thought it could have been, and that kind of makes you wonder, why do you want to go down that route?” Ferreira added.
The researcher believes it’s most likely that scientists will debate different models of dark energy and “never resolve it.”
Yet, there’s still a chance researchers could observe gravity being influenced by dark energy in upcoming observations by the European Space Agency’s Euclid satellite and DESI.
More on dark energy: Scientists Say They’ve Built a “Black Hole Bomb”
