An unknown anomaly discovered in the Cosmic Microwave Background (CMB) map—the residual signal from the earliest moments of the Universe—continues to be a subject of debate among scientists. This phenomenon, named the 'Axis of Evil' (Eixo do Mal), shows an unexpected alignment with the region occupied by the Solar System.
This discovery is related to measurements of the light left over from the Big Bang, obtained by space missions analyzing minor temperature fluctuations across the sky. The problem arose when researchers noticed that some of the largest patterns of this radiation seemed to follow a specific direction.
This case attracted attention because, according to modern cosmological models, the Universe should appear the same in all directions when observed on large scales. The possibility of a preferred orientation calls into question whether this effect is real or if it is due to observational limitations.
The CMB is a thermal signal filling the observable Universe and serves as a kind of chronicle of the first moments after the Big Bang. First detected in 1964, it became one of the key pieces of evidence supporting the model describing the origin and evolution of the cosmos.
The history of this mystery began with the discovery of the CMB in 1964 by physicists Arno Penzias and Robert Wilson. During observations with a radio telescope, they recorded a constant noise that did not depend on the direction the instrument was pointed. After ruling out terrestrial interference and even the presence of pigeons on the antenna, the pair concluded that the signal originated from a much more distant source. This phenomenon turned out to be radiation predicted as a consequence of the Big Bang, representing a thermal record of the early periods of the cosmos.
This discovery strengthened the Big Bang model because the observed radiation matched theoretical predictions. However, the same source of information that helped understand the origin of the Universe also revealed a number of unresolved questions, including the anomaly called the 'Axis of Evil'. This name appeared in 2005 when researchers analyzed large-scale structures on the relic radiation map and found a possible coincidence between certain patterns.
To study these small differences in temperature, astronomers divide the sky map into mathematical structures called multipoles. The dipole divides the observation into two hemispheres, while more complex patterns, such as the quadrupole and octopole, allow for the assessment of distributions in larger areas. According to the cosmological principle, these variations are expected to be distributed randomly, without any dominant special direction. Nevertheless, some studies indicate that the axes associated with the largest radiation patterns appeared to be aligned with each other.
The phenomenon became even more intriguing because this apparent direction coincides with the direction associated with our Solar System. Regions above and below this axis show small temperature differences on the CMB map. Researchers consider this coincidence unlikely, as the large-scale Universe should not reflect the position of any specific planetary system. Therefore, one hypothesis is that the effect may be related to how the data were collected or processed.
Another possibility considered by scientists is that structures close to our region might influence the separation between local signals and radiation that truly originated in the dawn of the Universe. Distinguishing these influences is a complex task. Currently, there is no consensus on the origin of this alignment. Scientists continue to investigate whether the axis represents a real feature of the cosmos, a result of observation methods, or interference caused by nearby phenomena. If the anomaly is confirmed in the future, it could pose a challenge to current cosmological models. For now, the so-called 'Axis of Evil' remains one of the most enigmatic features of observing the Universe.
A physicist has experimentally observed the emergence of time from a completely isolated quantum system by constructing what is called a 'mini-universe'. This experiment addresses the fundamental question of how time can exist if the universe lacks external references.
Giovanni Barontini, an experimental physicist at the University of Birmingham, published a new study on June 11th in the journal Physical Review Research. To conduct this unique experiment, he used a cloud of extremely cold atoms to configure his mini-universe. The system was isolated in such a way that, like the universe, there was no external element that could serve as a temporal reference.
Barontini proceeded by dividing the system into two parts and chose to neglect one of them, designated as the 'dark sector,' in order to prove that time could originate entirely internally within the system. The results provide the first practical examination of why the universe possesses the temporal dimension.
This work investigates a dilemma that has fascinated the physics community for almost six decades. The Wheeler-DeWitt equation, a cornerstone of quantum gravity—an area dedicated to reconciling Einstein's theory of gravity with quantum mechanics—models the universe as a closed set, without any external time parameter. This raises the question about the origin of our perception of time.
The relational theory of time suggests that time is not a primary property of reality, but rather something that arises from the internal interactions of the universe, where one part of the system acts as a clock for another. However, this hypothesis had never been directly verified in a laboratory environment.
Barontini's inspiration came from a personal observation: he saw his son playing with assembly kits, which made him think that the process was analogous to what occurs in his own laboratories, where they create small replicas of reality using Bose-Einstein condensates.
To simulate a self-sufficient universe, Barontini confined the condensate in a trap and separated it in half with a thin laser beam. He carefully monitored one half, called the 'bright sector,' while intentionally ignoring the other, the 'dark sector.'
The atoms in the bright sector oscillated periodically within the trap, passing through and returning across the barrier. Barontini named the moments when the atoms invaded the bright sector as 'Big Bang' and the moments of emptying as 'Big Crunch,' a term associated with a theory of the universe's final collapse.
Subsequently, he tracked the transfer of entropy—a metric of disorder or energy dispersion in the system—between the two halves during the passage of the atoms. Instead of relying on laboratory time to sequence the events, he established an 'entropic time,' a clock defined exclusively by the flow of entropy between the two halves of the system: time progressed when there was an exchange of entropy and stopped in its absence.
The most notable aspect for Barontini was the coherence with which all elements aligned. The internal entropic time organized the events in the bright sector in a predictable manner, mirroring the order observed in the experiment. This work constitutes a practical validation of concepts discussed in quantum cosmology and thermodynamics for decades. Although it is not a categorical statement that time is an illusion, it represents the first time such ideas have been subjected to a quantitative and direct test in a laboratory.
