As humanity struggles to understand dark energy, the mysterious force causing the accelerating expansion of the universe, scientists are starting to wonder about something quite futuristic. Can computers do more? Well, initial results from a team that used artificial intelligence (AI) techniques to infer the effects of dark energy with unparalleled accuracy may hint at the answer. N: Yes.
The team, led by University College London scientist Niall Jeffrey, will work with the Dark Energy Survey Collaboration to create a supercomputer simulation of the universe using measurements of visible and dark matter. did. Dark energy helps push the universe in all directions, but dark matter is a mysterious form of matter that is invisible because it does not interact with light.
After creating the cosmological simulation, the crew used AI to extract an accurate map of the universe that covers the past seven billion years and shows the effects of dark energy. The research team’s resulting data represent a staggering 100 million galaxies spanning about 25% of the sky in Earth’s southern hemisphere. Without AI, many more observations would have been needed to create such a map using this data, which represents his first three years of observations from the Dark Energy Survey. This finding helps validate which models of cosmic evolution are viable when combined with dark energy dynamics, but rules out other models that may not.
“By using this AI approach, we ended up doubling the accuracy of dark energy measurements compared to using traditional methods to learn about dark energy from these data maps.” Jeffrey told Space.com. “Using standard methods, we would need four times as much data.
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“If we wanted to achieve this level of precision and understanding of dark energy without AI, we would need to collect the same data three more times in different parts of the sky, which equates to 300 more mappings,” Jeffrey said. added. A million galaxies. ”
dark energy problem
Dark energy is synonymous with a mysterious force that accelerates the expansion of the universe, pushing distant galaxies away from the Milky Way and galaxies from each other, faster and faster over time.
The current period of “cosmic inflation” is separate from the period that followed the birth of the universe after the Big Bang. It appears to have started after the initial expansion slowed and stopped.
Imagine asking your child to give you a push on a swing. After the initial force is applied, the swing slows down, but without pressing again, the swing suddenly starts moving again instead of stopping. That in itself is very strange, but there’s really more to it than that. Also, the swing suddenly begins to accelerate after resuming movement, increasing in height and speed. This is similar to what happens in space, where instead of swinging back and forth, the universe is bubbling outward.
You probably want to understand what was applying the extra “push” and causing the acceleration. Scientists feel the same way about dark energy, whatever it is, which appears to be putting additional cosmic pressure on the very fabric of the universe.
This desire is further complicated by the fact that dark energy makes up about 70% of the universe’s energy and matter budget, even though we don’t know what it is. Taking into account dark matter, which accounts for 25% of this budget and cannot be made from atoms we know well, such as the atoms that make up stars, planets, the moon, neutron stars, our bodies, and the cat next door. When we put it in, we only consider one element. In fact, about 5% of the entire universe is visibly accessible.
“We don’t really understand what dark energy is. It’s one of those weird things. It’s the energy inside the universe that’s trying to push everything away from each other as the expansion of the universe continues to accelerate. It’s just a word we use to describe a kind of extra power,’” Jeffrey said. “The Dark Energy Survey is trying to understand what dark energy is. The main thing we’re trying to do is ask the question: Is it a cosmological constant?”
The cosmological constant, represented by the Greek letter lambda, has a very long history with cosmologists. Albert Einstein first introduced the theory in 1915 to ensure that the equations of his revolutionary theory of gravity, General Relativity, supported what was known as a “static universe.”
However, this concept was called into question when Edwin Hubble’s observations of distant galaxies showed that the universe was expanding and was therefore expanding. do not have static. Einstein is said to have thrown the cosmological constant into the scientific trash, calling it his “greatest failure.”
But in 1998, two separate teams of astronomers observed distant supernovae and discovered that the universe was not only expanding, but appeared to be expanding at an accelerating rate. Dark energy was invented to explain the force behind this acceleration, and the cosmological constant was fished out of a virtual trash can.
Now, the cosmological constant lambda represents the vacuum energy in the background of the universe, and acts like an “anti-gravity” force that promotes the expansion of the universe. At present, the cosmological constant is the strongest evidence for dark energy.
“Compared to standard methods using the same dark matter map, we found that our results were thoroughly refined and are still consistent with the dark energy explained by the cosmological constant.” said Jeffrey. “Therefore, this result excludes some of the physical models of dark energy.”
However, this does not mean that the mystery of dark energy, or the headache that the cosmological constant represents, is alleviated.
“The worst prediction in the history of physics”
The cosmological constant remains a major problem for scientists.
That’s because observations of distant objects suggest a lambda value that is 120 orders of magnitude (10 followed by 119 zeros) smaller than what quantum physics predicts. There is a good reason why the cosmological constant has been described by some scientists as “the worst theoretical prediction in the history of physics.”
Jeffrey makes it clear. Although the team is pleased with these results, the study still cannot explain the wide gap between theory and observation.
“The difference is so large that it shows that our quantum mechanical theory is wrong,” he continued. “What these results tell us is what equations and what physical models explain how the universe expands, how gravity works, and how it pulls together everything that is made of matter in the universe. .”
The research team’s results also suggest that general relativity is the correct recipe for gravity, but do not rule out other gravity models that could explain the observed dark energy effects. Can not.
“At first glance, these results alone are consistent with general relativity, but there is still a lot of room for adjustment, as other theories about how dark energy and gravity work can also be considered,” Jeffrey said. he said.
This research uses AI to evaluate simulated models of the universe to find important patterns that humans might miss, thereby demonstrating the utility of looking for important dark energy clues. It’s proven.
“When you use these techniques, you get results as if you had taken that data three more times, which is pretty amazing,” Jeffrey says.
The UCL researchers point out that carrying out these studies will require a very specific form of AI that is well trained in discovering patterns in the universe. Cosmologists can’t simply feed space-based simulations into an AI system like they can type questions into ChatGPT and expect results.
“The problem with ChatGPT is that if you don’t know something, you just make it up,” he said. “What we want to know is when we know something and when we don’t know something. So we want to make sure that people interested in research that combines science and AI get reliable results. I think we still need a lot of growth.”
The Dark Energy Survey is expected to provide another six years of data, which, when combined with observations from the Euclid Telescope, launched in July 2023, should provide even more information about the large-scale structure of the universe. . This will help scientists refine cosmological models and create more accurate simulations of the universe, which could ultimately lead to answers to the dark energy puzzle.
“That means the simulated universes we generate are very realistic. In some ways, they could be more realistic than what we were able to achieve with old-fashioned methods. ” Jeffrey concluded. “It’s not just about accuracy, it’s about believing in these results and considering them trustworthy.”
The team’s research is available as a preprint on the paper repository arXiv.
