Scientists examining the most extensive map of the cosmos ever created have uncovered suggestions that our current comprehension of the universe may require significant revisions.
The study, which examined approximately 15 million galaxies and quasars covering 11 billion years of cosmic history, revealed that
dark energy
—the supposedly unchanging force propelling the rapid expansion of our cosmos—might be losing strength.
At the very least, according to the data gathered by the
Dark Energy Spectroscopic Instrument
(DESI) suggests that when combined with data obtained from star explosions, measurements of the cosmic microwave background, and effects of weak gravitational lensing, we can gain deeper insights.
Should their discoveries stand the test of time, it would indicate that one of the most enigmatic forces shaping our universe is far stranger than initially believed—suggesting significant issues with our present cosmic model. The research team’s findings have been documented in a recent publication.
multiple papers
On the preprint server arXiv and showcased on March 19 at the
The American Physical Society’s International Physics Conference
In Anaheim, California, thus they haven’t undergone peer review yet.
“As has been noted, the findings from DESI stand-alone align with the most straightforward interpretation of dark energy, suggesting a static cosmological constant,” stated co-author
David Schlegel
A DESI project scientist at the Lawrence Berkeley National Laboratory in California explained to Live Science, “While we focus on these recent findings, we cannot disregard additional information from earlier and later periods of the universe. It’s when we integrate [these new results] with previous observations that things become extraordinarily peculiar, suggesting that dark energy might be ‘dynamical,’ implying it varies over time.”
The evolving cosmos
Dark energy
and
dark matter
are two of the cosmos’ most enigmatic elements. Combined, they constitute
roughly 95%
Of the cosmos, yet since they don’t interact with light, they cannot be observed directly.
These elements remain crucial constituents of the prevailing Lambda-cold dark matter (Λ-CDM) framework in cosmology, which charts the development of the universe and forecasts its conclusion. According to this theory, dark matter ensures galaxies stay cohesive and justifies their surprisingly strong gravitational effects, whereas dark energy elucidates the speeding up of the universe’s expansion.
Related:
Could the cosmos cease from expanding at some point? A recent theory suggests a universal ‘shutdown mechanism.’
But despite
countless
observations
among these imagined malevolent beings
shaping
our
universe
Scientists remain uncertain about their origin and nature. The most compelling theoretical framework for understanding dark energy comes from quantum field theory, which posits that the emptiness of space is teeming with a vast ocean of particles and fields.
quantum fields
those fluctuations generate an inherent energy density within vacant space.
Following the Big Bang, this energy intensifies as space expands, generating additional vacuum and more energy to drive the universe’s accelerated expansion. This proposal assisted researchers in linking dark energy to the phenomenon.
cosmological constant
—a theoretical inflatory force, expanding alongside the continuum of spacetime across the lifetime of the universe. Einstein referred to this as Lambda in his theory of relativity.
general relativity
.
“The issue with that theory is that the figures don’t match up,” he stated.
Catherine Heymans
A professor of astrophysics at the University of Edinburgh and the Astronomer Royal for Scotland, who wasn’t part of the research team, explained, “If you ask, ‘What kind of energy should I anticipate coming from such a vacuum?’ The answer is vastly different from what we actually observe.” She shared these insights with Live Science.
She also noted, ‘It’s quite thrilling that the universe has presented us with an unexpected twist.’
Scanning the dark universe
To determine whether dark energy has varied with time, astronomers utilized three years of data collected by DESI, an instrument installed on the Nicholas U. Mayall 4-meter Telescope located in Arizona. This device tracks the monthly locations of millions of galaxies to examine the expansion history of the universe extending to contemporary times.
By compiling DESI’s observations, which includes nearly 15 million of the best measured galaxies and quasars (ultra-bright objects powered by supermassive black holes), the researchers came up with a strange result.
Taken on their own, the telescope’s observations are in “weak tension” with the Lambda-CDM model, suggesting dark energy may be losing strength as the universe ages, but without enough statistical significance to break with the model.
However, when combined with other observations, like the cosmic microwave background radiation left over from the
cosmic microwave background
From the study of supernovae and the gravitational lensing of light from far-off galaxies, evidence suggests that dark energy might be undergoing changes over time.
Actually, it extends the discrepancy between the observations and the standard model up to 4.2Sigma, a statistical measurement on the verge of significance.
five-Sigma result
Physicists employ this as the “gold standard” when announcing a novel finding.
Related:
Following two years in space, the James Webb telescope has disrupted cosmology. Is there a way to resolve this issue?
Whether this result will hold or fade over time with more data is unclear, but astrophysicists are growing confident that the discrepancy is less likely to disappear.
“These data seem to indicate that either dark energy is becoming less important today, or it was more important early in the universe,” Schlegel said.
Astronomers say that further answers will come from a flotilla of new experiments investigating the nature of dark matter and dark energy in our universe. These include the
Euclid space telescope
, NASA’s
Nancy Grace Roman Space Telescope
, and DESI itself, which is currently in its fourth year out of five total years dedicated to surveying the sky, aims to catalog data from 50 million galaxies and quasars upon completion.
It seems reasonable to state that when viewed superficially, this outcome represents the most significant indication we’ve had regarding the character of dark energy since our discovery of it roughly 25 years ago,
Adam Riess
, an astronomy professor at Johns Hopkins University who
received the 2011 Nobel Prize in Physics
For his team’s 1998 revelation of dark energy, he shared with Live Science, “Should this be substantiated, it would imply that dark energy isn’t merely an unchanging form of energy as many believe, but possibly something far more peculiar.”
