2024 was a big year for space science in many ways, but it may prove to be the most important year for the most disturbing and mysterious “mixture” in the universe, dark energy, since its discovery about thirty years ago. This was the first year that scientists received the exciting warning that the force driving the rapid expansion of the universe could be “growing.”
Dark energy is a serious problem for scientists. Representing 68% of the total energy budget of the universe, this is the driving force to accelerate the expansion of the universe. This phenomenon is different from the initial inflation of the universe that was triggered by the Big Bang, which almost stopped when dark energy took over!
To see why that’s a concern, imagine giving a child one push while they’re pushing, watching their movement stop, and then, for no apparent reason, start rocking again , and this movement is even faster.
This latest acceleration was discovered in 1998 by two groups of astronomers making space measurements using supernovae in distant galaxies. “Dark Power” was simply the name of the image given to the power that drives this race, in the hope that eventually, a more accurate concept and name will emerge.
Related: What is dark energy?
Although dark energy is still in our universe, its presence serves as a reminder that the main ingredient of the universe is still a mystery. You could compare this to Colonel Sanders’ secret blend of herbs and spices, but it’s like eating KFC and not knowing what the chicken is or where it comes from! Disturbing indeed.
Although 2024 did not provide a complete answer to this mystery more than 25 years earlier, an important light has emerged in the armor of dark forces, a mysterious light that could put scientists on the way the right way to solve this universal problem. puzzle.
2024 was the year of DESI
These new discoveries of dark energy come thanks to the first year of data provided by the Dark Energy Spectroscopic Instrument (DESI), which has resulted in one of the deepest maps of the universe ever. done.
DESI’s 5,000 robotic eyes collect light from millions of galaxies across more than a third of Earth’s sky, separating it into many colors. DESI data allowed scientists to measure the change in wavelength of light from distant galaxies as they move away from us through the increasing fabric of space-time, a phenomenon called “redshift .”
The DESI results have given scientists a clue that dark energy is changing over time. In particular, it seems that this magical power is weak.
This is important, as in our current model of cosmology – the Standard or Lambda Cold Dark Matter Model (LCDM) – dark energy is represented by a “cosmological constant” (symbolized by the Greek letter lambda). It is called the “cosmological constant”. becoming constant over time in the LCDM model.
“The release of these results was a good day for cosmology, pointing to the effect of the ‘decreasing’ of dark energy over time, which means that it is continuing, therefore, not change after all,” Luz Ángela García Peñaloza, former DESI team member. and a cosmologist at Universidad ECCI Colombia, told Space.com in April 2024 when the DESI data came down. “The discovery of the changing dark energy would be as revolutionary as the discovery of the rapid expansion of the universe itself if confirmed by future data.”
Space.com met with García Peñaloza to reflect on the impact of this discovery and to discuss how future cosmologists can look back to 2024.
“Until this year, most expectations were in agreement, and dark energy was a stable phenomenon of the universe. However, 2024 was full of evidence that this may not be I’m not like that,” said García Peñaloza. “Many studies of the universe do not accept the existence of the universe, and instead, show promising results for dark energy to change over time.”
The power of darkness is becoming powerful!
The fact that dark energy could weaken, or change in any way, alarmed cosmologists. As García Peñaloza said, so far, observations have been consistent with the “equation of state” for the universe where the universe is constant, therefore, dark energy is constant in time.
García Peñaloza said that this disruption from that situation “opens a window” to models of the universe that include a time-varying form of dark energy. That would mean the permanent end of the universe and the emergence of “powerful dark forces.”
Another powerful theory of dark energy that was popularized by García Peñaloza even before the DESI results were available was the “early dark energy” (EDE) model. This theory revolves around the fact that, although dark forces rule the universe now, it wasn’t always like that.
Until about 4 to 5 billion years ago, matter dominated the universe, and before that, the radiation associated with the Big Bang was dominant. The EDE models suggest that dark energy did not come out of nowhere to start dominating the universe when it was between 9 and 10 billion years old; the forces of darkness had been there all along, playing an unforgettable role.
That means it’s dynamic and changing. Initial DESI data seems to support that idea.
Related: What is the Big Bang Theory?
Cosmologists will not be too sad to see the end of the universe, if it turns out that dark energy is really changing.
Predictions of the universe representing the “vacuum energy” of space made using the theory vary from expectations of this value by a magnitude of 10 to the power of 121 (ie 10 followed by 120 zeros).
It’s no wonder that the long universe has been a headache for cosmologists for decades and has been described as “the worst hypothesis in the history of physics.”
Let’s clear the lambda from the table too quickly, though. More information will be needed to overturn this model. And the data to do that is already on the way!
The DESI survey began operations at the Mayall Telescope atop Kitt Peak near Tucson, Arizona, in 2021, and is scheduled to run for five years, ending in 2026. from the first year of results.
To create a new concept of dark energy, scientists will need to see other data that suggest that this composition of the universe changes with time. Fortunately, DESI Year 2 and Year 3 scores are expected in Year 2025.
“Dark energy may be more consistent with DESI Year 1 observations than the universe,” said García Peñaloza. “What is said, it has not yet reached; it is only the details that like the dark energy like change. [phenomenon] than the usual cosmological candidate. Still, it’s fun.
“Maybe it’s too early to say that we solve this mystery, but I can say that we now know more about the behavior of this unknown compound.”
García Peñaloza explained what advances he expects in the science of dark energy in the coming year. DESI will be getting help in its mission to uncover the secrets of dark energy, he said, in the form of additional data from the Euclid telescope.
The European Space Agency’s (ESA’s) “dark energy probe” launched in July 2023, and since October of that year, has been wowing scientists with its amazing images of the universe. Next year, it may do the same with other hard points.
“First, Euclid will release the first data sets, which have been long awaited from the public. Also, other representatives of the universe on a large scale will publish their results that complement the latest discoveries -rao from the James Webb Space Telescope,” García Peñaloza. complete. “The most refined high-resolution simulations will continue to reveal new insights into what dark energy is and perhaps open up new unknown questions about the connection between darkness and other cosmic phenomena.”
Like the universe itself, our excitement for 2025 and the science it will provide is growing at a rapid pace!
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