The largest cosmic map may upend dark energy and prove Einstein wrong

• For decades, astronomers have been puzzling over dark energy and why it drives our universe apart.
• New data from the largest 3D map of our universe suggests we may be wrong about dark energy.
• Dark energy was thought to be an unchanging force, but it may not be so constant, after all.

Scientists have built the largest 3D map of our universe yet, and it comes with some interesting surprises.

“So far, we see basic agreement with our best model of the universe, but we also see some potentially interesting differences,” Michael Levy said in a statement issued by Lawrence Berkeley National Laboratory on Thursday.

Levy is the director of the dark energy analysis instrument, DESI, which produced the new map. The instrument consists of 5,000 small robots attached to a telescope in Arizona that collect light from different phases of the universe.

Astronomers use DESI to look back in time, billions of years ago, to understand how the universe changed and evolved. One of the driving forces behind this development is also one of the biggest mysteries of our time in physics: dark energy.

Dark energy is the name astronomers give to the unknown force that drives our universe to expand faster and faster as time passes. But since its discovery in 1998, dark energy has eluded scientists, who know little about what it is or why it behaves the way it does.

DESI's detailed map can change that. This suggests that dark energy may be very different from what scientists think, shaking a fundamental pillar of our understanding of the universe.

Dark energy may not be Einstein's constant after all

Dark energy, as we now understand it, is terrifying to think about because it means that our universe is expanding faster and faster until one day galaxies will move away from us so fast that their specks of light will disappear in the night sky. Existence.

This is the future we are headed to if dark energy continues at the rate it is going. Until Thursday, this is what many astronomers believed: that dark energy is a constant, unchanging force.

That's why astronomers thought dark energy could be the same as Albert Einstein's “cosmological constant,” which was an extension of his theory of general relativity. Einstein abandoned the idea as his “biggest mistake” in the 1930s, astrophysicist Ethan Segal said He explainsBut the persistent dark energy would have cleared him.

However, this mysterious force might not be so constant, after all.

Preliminary estimates from new DESI data suggest that dark energy may evolve and weaken. This is the new discovery announced by scientists at a meeting of the American Physical Society this week.

“If this is true, it will be the first real evidence we've had about the nature of dark energy in 25 years,” Adam Ries, a Nobel Prize winner for co-discovering dark energy, told Quanta magazine.

For now, this is just a hint. Quanta stated that the data is not strong enough to confirm or claim a discovery. But the hint is tempting.

“The idea that dark energy changes is very natural,” Paul Steinhardt, a cosmologist at Princeton University, told the magazine. If it were constant, “it would be the only form of energy that we know of that is completely constant in space and time.”

If subsequent data confirm these early hints of unstable dark energy, it would change what we know about the composition of the universe and its future. It will also bring scientists closer to solving the mystery of the accelerating expansion of the universe.

“If this holds up, it could light the way to a new and perhaps deeper understanding of the universe,” Rees said. “The next few years should be very revealing.”

“The Golden Age of Cosmology”

DESI measured the most distant part of the universe 8 to 11 billion years ago with record precision.

Other major observatories for mapping the universe will take to the skies in the coming years. The Vera C. Rubin Observatory is about to be outfitted with the world's largest digital camera, which will allow it to map the entire southern sky over the course of a decade, including more than 20 billion galaxies.

The European Space Agency's Euclid telescope is already in space, where its mission is to study dark energy. NASA's Nancy Grace Roman Space Telescope is expected to launch in 2027 and conduct its own investigation into the issue.

For its part, DESI aims to map 37 million galaxies by the end of its survey.

“We are in the golden age of cosmology, with large-scale surveys about to begin, and new techniques being developed to make optimal use of these data sets,” said Arnaud Di Mattia, a researcher at the French Center for Alternative and Atomic Energy. Energy Commission (CEA) and co-leader of the DESI team that interprets its cosmological data, said in the press release.

“We're all really excited to see if the new data will confirm the features we saw in our first-year sample and build a better understanding of the dynamics of our universe,” Mattea said.