The British "Guardian" reported that a latest study pointed out that even if extraterrestrial civilizations are really sending radio signals to the earth, these signals are likely to encounter "bad space weather" near their parent stars, thereby being severely disturbed, and eventually being quietly "lost contact" in our existing monitoring systems.
This research comes from the SETI Institute in Silicon Valley, which has long monitored the universe through radio telescopes, hoping to capture extremely narrow frequency spikes in the radio spectrum that are difficult to produce by natural celestial bodies as clues to "technosignatures." Researchers pointed out that stellar activities such as solar storms and plasma turbulence will have a "broadening" effect on these originally extremely narrow artificial signals, spreading their energy to a wider frequency band, making it difficult for conventional narrow-band searches to distinguish them from background noise.
Vishal Gajjar, the first author of the paper and a SETI astronomer, said that if the stellar environment near the planet emitting the signal fluctuates violently, the signal frequency will be stretched and smeared (smeared), and the peak intensity will decrease, easily falling below the detection threshold of the existing search algorithm. This may explain to a certain extent the long-term "radio silence" encountered in the "Technical Characteristic Search". The study, conducted by him and research assistant Grayce C Brown, has been published in The Astrophysical Journal.
The research team emphasizes that this conclusion reveals an important complication that has been overlooked in past search strategies: even if the alien emission source itself generates "ideal" extremely narrow-band signals, these signals may no longer maintain narrow-band characteristics when passing through the space of the local galaxy, especially the plasma environment close to the star. Plasma density disturbances in stellar winds and "explosive events" such as coronal mass ejections can change the spectrum shape of the signal at the beginning, weakening the probability of being recognized by the earth's monitoring system.
At a popular level, this means a situation that may seem like science fiction but is not entirely impossible: Alien civilizations may be trying to "talk" to us, but these messages have been scrambled beyond recognition by space storms as they travel through their own star systems. When they arrive on Earth, they are indistinguishable from cosmic noise, making them "inaudible" to humans.
To quantify this effect, the SETI team does not rely directly on distant stars. Instead, it first uses radio signals from spacecraft in the inner solar system to calibrate the impact of stellar activity on radio waves, and then extrapolates the resulting physical model to the environment around solar-like stars and more distant stars. Through this "from near to far" approach, they tried to more realistically restore the true appearance of signals from potential extraterrestrial emission sources after passing through the turbulent plasma environment around their parent stars.
Brown pointed out that the research results mean that the way to monitor the universe needs to be systematically adjusted. The traditional idea of only focusing on "extremely narrow-band spikes" cannot cover signals that have been broadened near the source. Future observation plans will not only carry out searches in higher frequency bands, but also need to incorporate modeling of the broadening effect of stellar activity into signal processing algorithms in order to better match the signal form that actually reaches the Earth, rather than staying in the textbook "ideal narrow band".
For decades, mankind has never stopped asking "are we alone in the universe?" and the debate surrounding unidentified flying objects (UFOs), now known as "unsolved anomalies" (UAPs), has also continued to heat up, spawning a large number of conspiracy theories and film and television works. In 2024, a former U.S. Department of Defense official even claimed during congressional testimony that government employees had been injured in contact with aliens, but this claim was not supported by substantial evidence. Earlier, David Grusch, a former intelligence official who was responsible for analyzing UAP, also claimed that the Pentagon had been secretly recovering and trying to "reverse engineer" crashed UAPs for a long time, which aroused widespread public attention.
However, Rep. Tim Burchett, the Tennessee Republican who leads the congressional UAP investigation team, publicly cooled down on Grush's claims, saying that there would be no "little green men" and flying saucers at the hearing, and that the public should not have high expectations. Ironically, Burchett himself has previously claimed that certain technologies mastered by the United States "violate existing laws of physics" and claimed that alien spacecraft have the ability to "turn humans into charcoal blocks."
Formal reports from the U.S. government in recent years have also continued to add fuel to the fire. A public report in 2024 showed that between May 2023 and June of the following year, more than 750 new UAP reports were reported, and some of these incidents still require further analysis and explanation. In the wider public sphere, former President Barack Obama once "half-jokingly" said in a podcast last year that aliens "are real". The next day, he hurriedly clarified through social media that he had not seen any evidence and that he had only gone too far in the atmosphere of the interview, rekindling discussions on the official position.
The political wrangling surrounding extraterrestrial topics also continues to ferment. Current U.S. President Donald Trump subsequently announced that he would authorize the declassification of all government files related to aliens, UFOs, and UAPs, saying that he might be able to help Obama "get out of trouble" by "declassifying documents." Trump told reporters aboard Air Force One that he was not sure whether extraterrestrials existed, but believed releasing the documents would help quell long-standing speculation.
In addition to all kinds of political noise and folk imagination, this new study by SETI attempts to explain "why we have not heard a clear response from alien civilizations" from a purely physical and celestial environment perspective. If the pessimistic answer in the past was "Maybe we are the only one in the universe," then this time, scientists have given another possibility: Maybe they have been talking, but the signal was rewritten into background noise that we cannot recognize when traveling through the storm-raging universe.