Researchers from the University of Sheffield (England) have developed a new theory suggesting that the mysterious substance holding galaxies together may be in harmony with a hidden fifth dimension. The goal of this research is to help explain one of the greatest mysteries of modern science—the true nature of dark matter.
Dark matter has been studied by scientists for decades and inspires works of science fiction. For example, it appears as vortices capable of destroying planets in the film 'Star Trek,' or as 'dust' sustaining the multiverse in Philip Pullman's fantasy trilogy 'His Dark Materials.' Despite this, it remains one of the most unresolved problems in physics.
Although this substance has never been directly observed, scientists are confident in its existence due to its intense gravitational influence. It acts as an invisible 'cosmic glue,' ensuring the cohesion of galaxies, but its composition and properties remain unknown.
The hypothesis that this substance might exist in an additional and hidden dimension has been discussed in recent years. However, researchers from the University of Sheffield claim to have made a step forward with a new theoretical model. This study, published in the journal Physical Review D, offers an explanation for the behavior of dark matter and the difficulties in detecting it.
According to this model, dark matter exists in an extra dimension hidden near a force-carrying particle known as the dark photon. The theory posits that the specific geometry and shape of this dimension lead to the precise alignment of these particles' masses. This alignment generates a phenomenon called dark matter resonance, which researchers compare to the operation of a musical instrument vibrating strongly when reaching the correct note.
Dr. Yu-Dai Tsai, a senior researcher at Dorothy Hodgkin's Royal Society at the University of Sheffield, told Phys.org that dark matter resonance is already considered an important idea for understanding both its origin and detection methods. He noted: 'Dark matter resonance is already known as a powerful idea with the potential to change our understanding of how dark matter was produced in the early Universe and how we search for it today.'
According to the scientist, previous models treated this resonance merely as a pre-assumed hypothesis. Tsai added: 'But many previous models of resonant dark matter viewed the resonance as an assumption. This work provides a possible deeper origin for it: the resonance may stem directly from the geometry of hidden dimensions.'
Tsai also stated that this mechanism could explain why dark matter interacted much more intensely during fundamental periods of cosmic history, remaining practically undetectable today. He emphasized: 'This resonance can make dark matter interactions much stronger during critical epochs of cosmic history, such as in the early Universe. It is important that the model allows for these strong past interactions while explaining why dark matter seems so inert and difficult to detect today.'
The researchers also point out that although resonant dark matter and extra dimensions were studied separately in previous works, these models required extremely precise tuning of particle masses to function. The new study suggests that this alignment is not a coincidence nor dependent on manual adjustment, but arises naturally from the mathematical structure of the hidden dimension itself.
For Tsai, understanding this mysterious substance would mark a significant breakthrough for science. He stated: 'Understanding dark matter would be a profound breakthrough in humanity's knowledge of the cosmos and what it is made of.'
He added that the new model opens up new avenues for future research. 'Our study offers physicists new clear goals in the search for dark matter, while simultaneously linking two of the greatest ideas in fundamental physics: the mystery of dark matter and the existence of hidden dimensions.'
Beyond the implications for understanding the Universe, the researchers note that the search for dark matter stimulates the development of technologies with practical applications. These include ultra-sensitive detectors, cryogenic systems, low-noise electronics, and quantum measurement technologies, which can contribute to progress in fields such as medicine, computing, and global communications.
An international team of experts has created a new method capable of identifying videos manipulated by artificial intelligence, known as deepfakes, achieving an average accuracy rate exceeding 95%.
This methodology, developed by researchers from the University of Tokyo in Japan and the Max Planck Institute for Informatics in Germany, innovates by not focusing on visual flaws. Instead, the system analyzes whether the facial expressions presented correspond naturally to the audio spoken by the person.
The researchers report that this system managed to detect manipulations that escaped existing detectors, marking a significant advance in creating more efficient tools against falsified content.
Experts point out that generative AI already produces images and videos almost indistinguishable from real recordings to the human eye. Although this technology has beneficial uses, it also increases the risks of fraud, identity theft, and the spread of disinformation, making the development of reliable identification methods a priority in AI research.
The authors explain that current most accurate deepfake detectors generally use supervised learning, trained with vast databases of authentic and altered videos. However, this model can suffer from overfitting, learning specific characteristics of certain falsification methods and losing efficiency against new techniques.
In contrast, unsupervised methods are trained only with true videos, making them more resistant to new technologies but typically showing lower accuracy. The new proposed technique is the first unsupervised approach that manages to combine a high detection rate with robustness, surpassing current supervised methods.
Instead of looking for inconsistencies in pixels or other visual artifacts, the system concentrates its analysis on natural facial movements. It uses the FLAME model, common in facial animation and computer graphics, which describes facial expressions through 53 mathematical parameters.
During development, the researchers pre-trained the model with over 450 hours of public videos. With this material, the model learned to anticipate which facial movements would naturally be expected from a specific soundtrack. After this initial training, the system can be personalized for an individual using only about 60 seconds of video, functioning as a personalized deepfake detector.
In the analysis phase, the software compares the facial movements observed in the video with those predicted based on the speech. Noticeable differences between these two datasets are interpreted as strong signs of manipulation. Vladislav Golyanik stated that combining unsupervised learning with FLAME-based facial analysis gives the approach special resistance against new deepfake generation methods, as well as distortions such as noise or image compression.
In tests conducted by the team, the method achieved an average accuracy above 95% across several scientific reference datasets, surpassing the performance of state-of-the-art techniques. A considerable challenge was the evaluation on a dataset created by the researchers themselves, containing videos generated by Sora 2, OpenAI's video generation tool.
While previous detectors showed results close to chance, the new system correctly identified almost 95% of the manipulated videos. Despite these advances, the researchers warn that the technology still has limitations, as it requires extensive pre-training on powerful hardware and currently does not operate in real time.
In the 'Your Digital Right' section of Olhar Digital News, key legal issues in the technology sector are discussed on Thursday. Privacy and security consultant Leandro Alvarenga highlights major legal topics and answers readers' questions.
The question arises regarding the limits of applying artificial intelligence in a corporate environment. Former employees of Meta filed accusations against the company, claiming it uses an AI-based system.
These accusations have reignited the discussion about the legal and moral boundaries of using artificial intelligence in companies.
Astronomers have announced a historic achievement—the first direct detection of an atmosphere around a rocky planet located within its star's habitable zone. This breakthrough marks a significant step forward in the search for worlds potentially capable of supporting life.
The planet, named LHS 1140 b, is located approximately 48 light-years from Earth. According to the results of the new study, its atmosphere contains helium. In addition to being the first rocky planet with a directly detected atmosphere, it is also the first of its kind found in the so-called habitable zone—the region around a star where temperatures could allow for liquid water on the surface.
Researchers assert that among known exoplanets, LHS 1140 b possesses the greatest number of habitability indicators. The study's lead author, Collin Cherubim, told Space.com that the direct detection of helium in the atmosphere is unprecedented for rocky exoplanets, and its location in the habitable zone adds immense interest for astrobiology and the search for life.
LHS 1140 b is an exoplanet, meaning a planet outside our solar system. It was initially discovered by astronomer Jason Dittman's team in 2017, and he is also involved in the current research. According to Dittman, years of observation were required for scientists to confirm the presence of an atmosphere.
He noted that although the planet was found about ten years ago, the conclusion regarding the atmosphere was only reached now. Dittman emphasized that the planet has a solid surface and is composed of rock. Although the exact nature of this surface is not yet known, the team considers the presence of water on the planet highly probable.
LHS 1140 b orbits a red dwarf—a star smaller and cooler than the Sun. Despite the planet being significantly closer to its star than Earth is to the Sun, this distance is sufficient to maintain temperatures compatible with the 'Goldilocks zone,' which is considered suitable for the existence of liquid water. Researchers believe that the recently discovered atmosphere may help preserve these conditions.
Cherubim hypothesized that the planet likely contains a lot of water. He added that if the atmosphere provides a greenhouse effect, then the conditions we consider habitable on Earth are likely to exist there and could support liquid water.
Although LHS 1140 b is not an exact copy of Earth, researchers point out two similarities: its composition is a rocky planet, likely with an iron core, and it is now known to have an atmosphere; and its temperature is suitable for liquid water on the surface, which is one of the key requirements for life as we know it on Earth.
Among over six thousand identified exoplanets, the direct confirmation of an atmosphere on a rocky planet in the habitable zone is a unique moment. One of the main challenges is that LHS 1140 b orbits a red dwarf—the most common type of star in the Milky Way, which is about one-third the size of the Sun. These stars remain active for a long time, emitting powerful bursts of radiation, such as solar flares and coronal mass ejections. Typically, such radiation completely destroys the atmospheres of nearby planets, which raised doubts about the ability of rocky planets around red dwarfs to retain an atmosphere over long periods.
Cherubim noted that this discovery demonstrates that at least this rocky planet has managed to retain its atmosphere for billions of years, which is a 'well-founded and reliable way to say yes: atmospheres can survive on rocky exoplanets.' Scientists also suggest that other gases besides helium might be present in the atmosphere, some of which may have been lost in the past due to intense stellar radiation. However, since the star is about six billion years old—several billion years older than the phase of this intense activity—the team believes the planet will continue to retain its atmosphere. Dittman mentioned that while some helium slowly escapes into space, a similar process occurs with Earth's own atmosphere.
The confirmation of the atmosphere resulted from a theoretical prediction developed by Collin Cherubim during his doctoral dissertation. He explained that it all started with a mathematical model created to study the evolution of rocky planets, from which he made a very specific prediction about this planet.
The researcher decided to apply a method usually used to study gas giants to a rocky planet, which was an unprecedented step. The results fully aligned with his model prediction, allowing the scientific method cycle to be completed.
To test the hypothesis, the team used the Warm Infrared Echelle Spectrograph (WINERED), installed at the Magellan Observatory in Chile. During the same observations, they tracked the transit of LHS 1140 b and another planet in front of its star. Spectroscopic analysis allowed them to identify chemical signatures in the atmospheres of both worlds. While one did not yield results, LHS 1140 b demonstrated a direct and undeniable signal of helium's presence.
Despite the importance of the finding, researchers emphasize that it does not mean the planet is habitable. Cherubim clarified that he is not claiming there is life on the planet. In the team's view, future observations will allow for the detection of other gases in the atmosphere and the verification of water. Although new research may not confirm habitability or discover life forms, it will significantly expand knowledge about rocky planets of this type. Since LHS 1140 b is the first planet with these characteristics whose atmosphere has been confirmed, it represents an important step toward understanding the evolution of potentially habitable planets and may help answer one of humanity's oldest questions: are we alone in the Universe?
