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🤖 AI doesn't just help you write, it also shapes how you think
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🤖✍️ TECHNOLOGY AND PSYCHOLOGY AI doesn't just help you write, it also shapes how you think A Cornell Tech study published in Science Advances reveals that AI writing assistants crowd out our attitudes about social issues, even when we know they're biased midire.ar |
📰 TECHNOLOGY · PSYCHOLOGY · ARTIFICIAL INTELLIGENCE
AI doesn't just help you write: Cornell Tech study reveals it shapes how you think
⏱️ Estimated reading time: 9 minutes | 📅 Updated: September 2026
"Participants who used the biased assistant ended up incorporating that posture into their own attitudes, not realizing that a change had occurred."
Every time Gmail suggests you finish a sentence, every time Word's proofreader proposes a word, or every time a chatbot completes a paragraph for you, something other than text is passing from the machine to the person. A study published in March 2026 in the journal Science Advances, conducted by a team of researchers at Cornell Tech, found strong evidence that AI-based writing assistants don't just change how we write: they also displace what we think about social and political issues, without the person noticing it, and without explicit warnings being able to prevent it.
🔍 The Silent Influence of Autocomplete
The research, entitled "Biased AI Writing Assistants Shift Users' Attitudes on Societal Issues", was led by Sterling Williams-Ceci, a PhD candidate in information sciences at Cornell Tech, together with Maurice Jakesch, Advait Bhat, Kowe Kadoma, Lior Zalmanson and Professor Mor Naaman, with the participation of researchers from the University of Washington and Tel Aviv University.
The team designed writing assistants that offered deliberately biased autocomplete suggestions as participants drafted texts on topics of public debate. The central finding: The opinions of those who used the biased assistant tended to shift toward the stance implicit in those suggestions, and that change held up after the exercise, in subsequent surveys.
As Mor Naaman, professor of information science at Cornell Tech and senior author of the study, explained, the concern is not minor: language models not only produce neutral information, but can generate biased content depending on how they were trained or implemented, which opens the door for them to induce — unintentionally or deliberately — people to write and end up holding biased views.
🖼️ View image: Cornell Tech campus on Roosevelt Island, New York (Wikimedia Commons)
Credit: Wikimedia Commons — public domain/free license
🧪 Two experiments, more than 2,500 participants
To test the phenomenon, the team conducted two large-scale experiments with more than 2,500 volunteers. In the first, participants wrote a short essay on the use of standardized tests in education. One group received autocomplete suggestions that favored exams; another wrote without any assistance; and a third group simply received a list of arguments in favor, with no autocomplete built into writing.
The result made a key difference: those who used the biased assistant were later significantly more inclined to support standardized tests, while the group that only read a list of arguments changed their minds much less. That is, the mechanism is not simply exposure to a persuasive argument: it is the act of writing it oneself, with the help of the machine, that produces the scrolling.
The second experiment expanded the universe of topics to more polarizing issues: the death penalty, fracking, genetically modified organisms, and the right to vote for people with criminal records. In each case, the system was programmed to favor one position—liberal on the death penalty and GMOs, conservative on fracking, and ex-convict voting—and in all cases the same pattern was repeated: attitudes shifted toward the position suggested by the AI, regardless of the participant's previous political orientation.
⚠️ Not even explicit warnings managed to stop him
"We told people, before and after, to be careful, that AI was going to be biased. And nothing helped: their attitudes on the issues shifted the same."
Perhaps the most disturbing finding of the study is that even explicitly warning participants failed to reduce the system's influence. The researchers informed a portion of the volunteers, before or after the exercise, that the writing assistant was designed to offer biased suggestions. Even so, their attitudes continued to shift toward the position suggested by the algorithm.
This result contradicts some of the previous literature on misinformation, which had shown that warning people before exposing them to misleading information — or explaining it to them afterwards — can act as a kind of "cognitive vaccine." According to Williams-Ceci, the team expected that same defense mechanism to work here, and was surprised to find that it didn't.
The explanation proposed by the authors is rooted in a well-known principle of social psychology: our attitudes not only guide our actions, but can also be shaped by what we do. When a person writes arguments in favor of a position—even if they were not convinced at first—there is a natural tendency to gradually align their beliefs with what they have expressed in writing. The difference from traditional disinformation is subtle but decisive: autocomplete suggestions are not presented as external arguments to be critically evaluated, but as linguistic fragments that are integrated into the act of writing itself.
📊 The numbers of the study
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Fact |
Detail |
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Publication |
Science Advances, March 11, 2026 |
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Leading institution |
Cornell Tech (Cornell University) |
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Lead Author |
Sterling Williams-Ceci |
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Total participants |
More than 2,500, in two experiments |
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Attitude shift |
+0.44 points on a scale of 1 to 5 (95% CI: 0.21–0.67) |
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Topics evaluated |
Standardized Tests, Death Penalty, Fracking, GMOs, Ex-Con Voting |
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Effect of warnings |
Null: neither before nor after exercise did they reduce displacement |
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Financing |
National Science Foundation y German National Academic Foundation |
💬 The rise of autocomplete in everyday life
The phenomenon is not exotic or laboratory-like: autocomplete systems are already integrated into email, word processors, messaging platforms and, increasingly, social networks. Millions of people interact daily with these tools, which promise efficiency and convenience, capable of proposing complete sentences, summarizing ideas or composing entire messages.
This collaboration between humans and machines brings obvious benefits in speed and clarity, but it also opens up a new front of debate about the role of artificial intelligence in forming opinions. The paradox, they point out, is profound: technology designed to help us express ideas could end up participating in the formation of those same ideas. In this scenario, each autocomplete suggestion becomes a small intervention in the fabric of human thought.
🖼️ See image: Backlit keyboard, symbol of technology-mediated writing (Wikimedia Commons)
Credit: Wikimedia Commons — free license
🇦🇷 The discussion also reaches Argentina
The debate on the silent influence of AI is especially relevant in a country where the use of these tools is growing rapidly. According to Bumeran's "AI at Work" study, 57% of Argentine workers have already incorporated artificial intelligence into their daily tasks by mid-2026, two percentage points more than the previous year, and 99% of those who use it rated it as useful for their work.
In parallel, the global survey by KPMG together with the University of Melbourne – which surveys more than 48,000 people in 47 countries – placed Argentina among the emerging markets with the highest confidence in AI, well above the average for advanced economies. However, that same survey found that 70% of Argentines consider specific regulation necessary, and 87% call for laws and fact-checking mechanisms to combat disinformation: a tension that the Cornell Tech study illuminates from a different angle, less visible than fake news, but potentially more difficult to detect.
❓ Frequently Asked Questions
▪ What exactly did the Cornell Tech study find?
That AI writing assistants that offer biased autocomplete suggestions can shift writers' attitudes toward the stance implicit in those suggestions, including on topics of social and political debate, and that effect persists after the writing session.
▪ Do people realize that their opinion is changing?
No. According to the authors, the vast majority of participants, including those whose attitudes shifted most strongly, were not aware of the system's bias and the influence it had had on them.
▪ Does warning about system bias help avoid it?
The study shows that it does not: neither warning before the exercise nor explaining it afterwards reduced the shift in attitudes towards the position suggested by the AI.
▪ On what topics was the effect tested?
On standardized tests in education, the death penalty, fracking, genetically modified organisms (GMOs), and voting rights for people with criminal records.
▪ Where was the research published?
In the scientific journal Science Advances, on March 11, 2026, under the title "Biased AI Writing Assistants Shift Users' Attitudes on Societal Issues".
🧭 What lies ahead
The authors themselves stress that the problem is no longer hypothetical: just a few years ago, the possibility that an AI system was purposely biased sounded like science fiction; today it is a plausible scenario, openly discussed in the design of commercial products. If those biases are incorporated into tools used by millions of people—from a word processor proofreader to a customer service chatbot—the impact could extend far beyond the simple writing of an email or a school essay.
There are no persuasive speeches in between, no explicit propaganda: just a sentence that appears on the screen, inviting us to complete it. And in that daily gesture of accepting the suggestion, the boundary between what we think and what the machine proposes begins to blur.
📚 References
Williams-Ceci, S., Jakesch, M., Bhat, A., Kadoma, K., Zalmanson, L. y Naaman, M. (2026). Biased AI Writing Assistants Shift Users' Attitudes on Societal Issues. Science Advances. DOI: 10.1126/sciadv.adw5578.
Journalistic source: Muy Interesante — okdiario.com, article by Sergio Parra (12/03/2026)
Local data: Bumeran — "57% of Argentines already use AI in their work", iProfesional
Local data: KPMG / University of Melbourne — Forbes Argentina
"ZOMBIE" CELLS? Cells that activate a death signal, survive and help rebuild damaged tissue
- by
cronywell
SCIENCE · CELL BIOLOGY · REGENERATION
"ZOMBIE" CELLS?
Cells that activate a death signal, survive and help rebuild damaged tissue
Approximate reading time: 8–10 minutes · Updated: September 2026
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SEO Title |
"Zombie" cells? How some cells survive apoptosis and regenerate tissues |
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Meta Description |
Researchers discovered DARE and NARE cells that resist cell death and are involved in tissue regeneration after injury. |
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Suggested Slug |
cells-zombies-apoptosis-regeneration-tissues-dare-nare |
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Primary Keyword |
Zombie Cells |
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Keywords secundarias |
apoptosis, DARE cells, NARE cells, tissue regeneration, caspases, Dronc, cell resistance |
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Search intent |
Informative / scientific dissemination |
🧬 A story that seems like science fiction, but is born from experimental biology.
Research published in Nature Communications in December 2025 described two populations of epithelial cells that, in a model of Drosophila melanogaster —the fruit fly—, resist processes that normally lead to cell death and actively participate in regeneration after damage caused by ionizing radiation. The researchers named them DARE and NARE.
The news is usually summarized with the expression "zombie cells", but the term requires important precision: these cells are not the same "zombie cells" in the literature on cellular senescence. In this study, these are apoptosis-resistant cells that retain proliferative capacity and, in the case of DAREs, activate an initial signal of the apoptotic pathway without completing the death program.
🖼️ Recommended Scientific Images
The following images come from the Weizmann Institute of Science and show the epithelial tissue of the fly and the cells associated with the regeneration process. To respect provenance and rights of use, the document includes the absolute links to the original files.
🔗 Figure 1 — epithelial tissue before/after the damage (Weizmann Institute)
🔗 Image 2 — microscopic image associated with the study (Weizmann Institute)
🔗 Institutional page with context, authors and captions
🔬 The finding: cells that refuse to follow the script of death
Under normal conditions, apoptosis is one of the fundamental mechanisms by which an organism eliminates damaged, unnecessary, or potentially dangerous cells. The process is carefully regulated and depends on a family of enzymes called caspases. An initiating caspase activates a cascade that, if it progresses to the executing caspases, disassembles the cell in an orderly fashion.
The team led by Tslil Braun and Eli Arama of the Weizmann Institute of Science looked for precisely cells that had triggered an early signal of apoptosis but were still alive. To do this, they used genetic tools and a delayed sensor that identified cells in which the initiator caspase Dronc had been activated.
The result was the identification of DARE (Dronc-Activating Regeneration Enhancing) cells, capable of surviving an attack that causes apoptosis in many neighboring cells. After irradiation, these cells proliferated and contributed to tissue repair. The study indicates that their descendants managed to replace about half of the affected tissue in approximately 48 hours.
🧩 DARE and NARE: Two Populations, Different Functions
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Population |
Main feature |
Observed role |
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DARE |
Activates Dronc, but prevents the apoptotic cascade from reaching a full death. |
It boosts regeneration and can stimulate neighboring cells. |
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NARE |
It does not show activation of Dronc initiator caspase under the conditions studied. |
It participates in tissue repopulation and receives signals from DAREs. |
⚙️ How do they manage to survive?
The study provides a key piece of the mechanism. In DAREs, activation of Dronc does not automatically trigger the entire destructive cascade. The researchers implicated Myo1D, a molecular motor-associated protein, in the survival of these cells. Experimental evidence indicates that Myo1D helps keep the initiating caspase in a situation that prevents lethal activation of the executing caspases.
When the researchers silenced this protein, the DARE cells lost their ability to survive and tissue regeneration deteriorated. The finding is important because it shows that the same molecular machinery can participate in two apparently opposite outcomes: promoting cell death in a context and, under certain conditions, contributing to survival and repair.
🌱 When one cell dies activates the repair of others
Regeneration also does not occur in isolation. Cells that die after damage appear to emit signals capable of activating DAREs. From there, DAREs proliferate and promote the proliferation of nearby NARE cells.
The researchers also observed a negative feedback mechanism: DAREs stimulate the growth of NAREs, while NAREs produce signals that slow down the growth of DAREs. This circuit helps prevent a repair response from turning into uncontrolled growth.
In simple terms, tissue appears to use a combination of alarm, survival, expansion, and brake. Cell death is not just a loss: it can also become a signal that organizes reconstruction.
🛡️ The data that attracted the most attention: resistance in the descendants
The most striking aspect appears when the tissue is irradiated again. The researchers observed that, during the first hours of a second exposure, about half of the cells that had died during the first exposure died. In addition, the descendants of the DAREs were about seven times more resistant to cell death than the cells of the original tissue.
This does not mean that the cells have become "immortal". It means that, in the experimental model and under the conditions analyzed, the descendants of the DAREs showed much greater resistance to damage than the initial cells. That difference may be relevant to understanding how some tissues survive repeated aggressions.
The authors suggest that the mechanism could help to understand a known problem in oncology: some tumors that recur after treatment may have resistant populations. However, the study does not prove that this mechanism is, by itself, the explanation for the resistance of human tumors.
⚠️ "Zombie cells" doesn't mean the same thing in every study
Here is one of the main keys to correctly interpreting the news. In biology, "zombie cells" is often used as a popular expression for senescent cells: cells that stop dividing, remain metabolically active and can release molecules that modify the behavior of the tissue.
The DAREs and NAREs in the Weizmann Institute study should not be automatically confused with those senescent cells. In fact, independent work has shown that certain senescent cells can play beneficial roles during tissue repair, while other senescent populations can contribute to inflammation and disease. Cell biology is therefore much more nuanced than the picture of a simply "good" or "bad" cell.
In 2026, for example, a study published in Nature Cell Biology described a rapid senescence response in skin cells after an injury and found that this response is involved in repair. That work is relevant to the overall context of "cells that appear damaged but help repair," but it's not the same mechanism as the one described for DARE/NARE.
🧪 Was the discovery made in humans?
No. The central study was conducted using Drosophila melanogaster and, in particular, epithelial tissue related to wing development. This point is critical. Just because a molecular pathway exists in a model organism and can have equivalents in other animals does not mean that the same behavior has been demonstrated in humans.
The fruit fly is a widely used model in genetics and developmental biology because numerous cellular pathways are conserved between species. So the results can guide further research. But it still needs to be shown which equivalent cells exist in human tissues, how they are regulated, and whether they produce comparable benefits or risks.
🧠 Why may this finding be important for medicine?
The first possibility lies in regeneration. If it is possible to understand how cells survive intense damage and coordinate repair, new strategies could appear to improve healing or the recovery of certain tissues. The authors themselves suggest that these mechanisms could help to develop ways to accelerate regeneration after an injury.
The second possibility is in oncology. If a cell manages to avoid apoptosis after suffering genetic damage, that ability can be useful for healthy tissue that needs to be repaired, but it could also be problematic if a tumor cell uses similar mechanisms to escape treatment.
The third issue is therapeutic: the challenge is not simply to increase cell resistance. The goal would be to learn how to control when that resistance is beneficial and when it can promote abnormal growth. The research is still at a basic stage and is not a treatment available to patients.
🔭 A Shift in Perspective on Apoptosis
For a long time, apoptosis was primarily presented as the mechanism by which a cell "commits suicide" to protect the organism. Modern research has shown that caspases may have additional functions and that signaling associated with death may influence processes such as proliferation, repair, and response to damage.
The work of Braun and his colleagues adds a particularly interesting piece: some cells can activate a part of the apoptotic machinery and, without completing the death process, convert that signal into a regenerative advantage. The boundary between "death," "survival," and "repair" thus becomes much less rigid than simplified definitions suggest.
📌 What we know and what we don't know yet
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Current Evidence |
Open question |
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DARE and NARE were identified in Drosophila tissue after radiation. |
Are there equivalent populations with comparable functions in humans? |
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DARE can activate Dronc and prevent a complete apoptotic death. |
What factors determine whether a cell takes this path in different tissues? |
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DAREs drive regenerative proliferation, and NAREs also contribute. |
Can this circuit be manipulated without increasing the risk of abnormal growth? |
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The DARE descendants showed about seven times greater resistance. |
How long does that resistance last and how is it inherited or maintained? |
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The mechanism could provide clues about tumor resistance. |
Can it become a safe therapeutic target against human cancers? |
🧾 Conclusion
The term "zombie cells" is attractive to describe this discovery, but the scientific reality is even more interesting. The researchers identified DARE cells that, in a fruit fly model, activate a signal associated with apoptosis, survive an attack that kills other cells, proliferate, and help rebuild tissue. They also identified NARE cells that are involved in regeneration and a signal circuit that limits growth.
The fact that the descendants of DAREs were much more resistant to a second injury opens up a question of great interest to biology and medicine: how can a cell convert an experience of damage into a subsequent ability to survive? The answer could contribute both to improving tissue regeneration and to understanding why some cells, including certain cancer cells, manage to resist therapeutic aggressions.
For now, however, it is convenient to separate the evidence from the expectations. The finding is solid within the experimental model used, but it does not yet demonstrate a therapy for humans or allow us to affirm that there are "zombie cells" with identical behavior in our body.
📚 Scientific sources and absolute links
🔗 Nature Communications — original article, published December 4, 2025
🔗 Weizmann Institute of Science — Resurrected Tissue, 24 de diciembre de 2025
🔗 eLife / PMC — regeneration after necrosis and non-apoptotic caspase activity
🔗 Nature Cell Biology — rapid senescence during healing, 2026
🔗 PubMed — abstract of the study on rapid senescence and repair
Can we travel back in time?
- by
cronywell
SCIENTIFIC DISSEMINATION · PHYSICS AND COSMOLOGY
Can we travel back in time?
What relativity, wormholes, and quantum physics really say about crossing time
🕒 Estimated reading time: 11-12 minutes · ✍️ Writing for popular science
📅 Updated: September 2026
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🧭 In summary Traveling into the future is already a measured and proven reality: it is enough to move very fast or get close to an intense gravitational field. Traveling into the past, on the other hand, is still mathematically possible in some solutions of general relativity, but it comes up against physical, energetic and logical barriers that no experiment has managed to overcome. This report follows both paths with the most recent evidence. |
🚀 A dream as old as science fiction
From H. G. Wells to Back to the Future, the idea of getting on a machine and scrolling through the calendar has fascinated entire generations. But far from being just a narrative device, time travel has been, for more than a century, an object of serious study within theoretical physics. The question that is the title of this article does not admit a simple yes or no: the answer depends on which direction of time one wants to travel, forward or backward, and what nature is willing to admit.
To understand this, it is necessary to abandon the idea of time as a river that flows equally for everyone. Albert Einstein demonstrated, first with special relativity (1905) and then with general relativity (1915), that time is one more dimension, intertwined with space in a single fabric called space-time. And that fabric can be stretched, curved and, according to some mathematical solutions, even knotted in on itself.
⏩ Traveling to the future: the part that is already solved
If the goal is to get ahead in time, the scientific answer is blunt: yes, it is possible, and it has already happened. The phenomenon is called time dilation and has two variants that relativity predicts with mathematical precision.
Speed: The faster you move, the slower your watch moves forward
Special relativity states that time passes slower for a moving object than for an observer at rest. The effect is minuscule at everyday speeds, but it becomes measurable in orbit. Astronauts on the International Space Station (ISS), traveling at about 28,000 km/h, age a fraction of a second slower than those who remain on Earth.
🛰️ Cosmonaut Gennady Padalka, with more than 878 days accumulated in space, is today the person who has "travelled" the most into the future due to this effect: a fraction of a second ahead of the rest of humanity.
👬 The case of twins Scott and Mark Kelly — one of whom spent 340 consecutive days on the ISS — allowed NASA to directly compare the biological and temporal effects of long-duration spaceflight.
Gravity: the stronger the gravitational field, the slower the clock
General relativity adds a second ingredient: clocks located in a stronger gravitational field—near a massive planet or black hole—move more slowly than those farther away. That's why GPS satellites must correct their atomic clocks several times a day: without that adjustment, the positioning system would accumulate errors of several kilometers in a matter of hours.
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⚫ Date clave An object orbiting very close to a supermassive black hole, at the edge of its event horizon, could experience only a few years while the rest of the universe would elapse centuries or millennia. It is, in essence, the mechanism used by the movie Interstellar for its iconic giant tidal planet. |
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🖼️ Artist's concept of a spinning black hole, according to general relativity Credit: Event Horizon Telescope (EHT) Collaboration — public domain/scientific use |
⏪ Traveling to the Past: The Unresolved Great Frontier
The real challenge—and the one that fuels all science fiction—is the backward journey. Here, physics doesn't say "no" outright, but neither does it offer a practicable "yes." Einstein's equations admit, in theory, exotic solutions known as closed time curves (CTCs): trajectories in space-time that, always moving into the local future, end up returning to their own starting point.
Wormholes: shortcuts between two points in space-time
The best-known proposal is the Einstein-Rosen bridges, described mathematically in 1935 and renamed wormholes. In 1988, physicists Kip Thorne and Michael Morris refined the model and showed that if one of these tunnels could be kept open and traversed, and if its two ends were also moving relative to each other at different speeds or gravities, the mathematical result would be a real time machine.
The problem is not geometric, but physical: keeping a wormhole open would require exotic matter, a form of energy with negative density that has never been observed in useful quantities. As astrophysicist Eric Davis explained, although these tunnels could connect different moments in time, turning them into a functional travel machine would require a technological and energetic effort that today is far ahead of any human capacity. Kip Thorne himself has pointed out that the laws of physics will probably end up prohibiting a human being from physically crossing one of these structures.
At the beginning of 2025, a team from Conicet and the National University of La Plata (Argentina) published a theoretical model – in the journal The European Physical Journal C – that proposes a way to distinguish a rotating wormhole from a common black hole, based on the electromagnetic pattern it would generate. It would be the first method capable of providing indirect observational evidence on whether these objects really exist in the universe, although for the moment it remains a hypothesis pending data from telescopes.
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🖼️ Conceptual illustration of a walkable wormhole, according to the Morris–Thorne model Credit: public domain / informative representation |
Warp motors: the other side of the same coin
In 1994, the Mexican physicist Miguel Alcubierre proposed another solution to Einstein's equations: a ship could, in theory, move faster than light without violating relativity if, instead of accelerating itself, it contracts the space in front of it and expands it behind, wrapped in a bubble of curvature. Alcubierre himself and other physicists have pointed out that this type of configuration, combined with certain geometries, could also give rise to closed time curves, that is, they would open an indirect door to the past.
The obstacle, again, is energetic: Alcubierre's metric requires the same exotic matter of negative energy as wormholes, in quantities that in the original calculations were equivalent to the mass-energy of an entire planet. Subsequent studies, such as those of the physicist Harold White, have explored geometric variations that would drastically reduce this requirement, although they remain, for now, mathematical exercises without experimental verification.
🌀 The paradoxes that test logic
Even if the technology to open a closed time curve existed one day, a deeper problem would remain: causality. The most cited example is the grandfather paradox, formulated by the French writer René Barjavel in 1943: if someone travels to the past and prevents the meeting of his own grandparents, how could he be born to undertake that journey?
🔁 Novikov's principle of self-consistency: proposes that the universe only allows trips to the past that are logically consistent; any attempt to alter history would end, by the laws of physics themselves, generating the same result that has already occurred.
🌐 Interpretation of branching universes: suggests that a trip to the past does not modify "your" timeline, but creates a different parallel reality, thus avoiding logical contradiction.
🛡️ Chronological protection conjecture: the most cited position among physicists, proposed by Stephen Hawking in 1992.
Hawking argued that even if general relativity mathematically allows closed time curves, some additional physical mechanism—probably tied to quantum effects, such as vacuum polarization—would prevent them from forming on a macroscopic scale, thus preventing travel into the past and its paradoxes. His way of summarizing it became famous: he joked about the existence of a kind of "chronological protection agency" that keeps the universe safe from historians. As informal evidence in favor of his own conjecture, he pointed out that humanity has never been "overrun by hordes of tourists from the future."
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🔬 And what does quantum physics say? Researchers from universities such as the Complutense University of Madrid and the CSIC have proposed and executed simulations of closed time curves in quantum and classical systems controlled in the laboratory. These experiments do not allow real-time travel, but they do allow us to study in miniature how information and causality would behave if these curves existed, providing indirect clues about the validity of Hawking's conjecture. |
📊 Comparison: theoretical routes to time travel
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Mechanism |
Theoretical basis |
Current status |
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Temporal dilation (velocity) |
Special Relativity (1905) |
Tested and measured on the ISS and in particle accelerators |
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Temporal dilation (gravity) |
General Relativity (1915) |
Checked; corrects GPS system clocks daily |
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Walkable wormhole |
Einstein-Rosen bridge / Morris-Thorne model |
Mathematically valid; requires exotic matter never observed |
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Bending motor (Alcubierre) |
Solution of the Alcubierre metric (1994) |
Theoretical; it requires negative energy in quantities that are unattainable today |
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Closed time curves |
Exotic Solutions of Einstein's Field Equations |
Possibly blocked by Hawking's chronological protection conjecture |
🧩 So, can we travel back in time or not?
The honest and up-to-date answer is twofold. Into the future, yes: physics allows it, predicts it with accuracy and has already been verified in astronauts, satellites and experiments with high-precision atomic clocks. Into the past, the door remains ajar only on paper: equations do not prohibit it absolutely, but each proposed path – wormholes, warp engines, closed time curves – runs into the same wall, the need for exotic matter or energy that no one has ever detected, and with the suspicion, increasingly consolidated among theoretical physicists, that the universe itself has mechanisms to prevent paradoxes before they even form.
While science continues to polish these models—with new tools such as next-generation telescopes and quantum laboratory simulations—the truth is that we already live, in a literal sense, surrounded by time travelers: every GPS satellite and every astronaut who returns to Earth brings with it, on its internal clock, a few seconds stolen from the future.
❓ Frequently asked questions about time travel
Is there any evidence that you can travel to the past?
No experiment has ever detected a closed time curve or matter with enough negative energy to sustain it; for now it is a purely mathematical and theoretical field.
Do astronauts really travel in time?
Yes, in the strict sense of time dilation: they return to Earth a fraction of a second younger than they would have been if they had stayed on the ground, an effect measured with atomic clocks.
Why is "exotic matter" needed and what exactly is it?
It is a hypothetical type of matter with negative energy density, needed in wormhole and warp motor models to keep space-time stable. It has not been observed in nature in appreciable quantities.
What do physicists think today about the real possibility of traveling to the past?
The majority position remains aligned with Hawking's chronological protection conjecture: even if general relativity does not mathematically prohibit it, some additional physical principle—probably quantum—would prevent these structures from forming in practice.
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📚 Sources and references
🔗 Infobae — What are wormholes and why are they linked to time travel?
🔗 National Geographic — What is a wormhole
🔗 La República — South American Theoretical Model for Detecting Wormholes (Conicet / UNLP)
🔗 Wikipedia (EN) — Chronology protection conjecture (Stephen Hawking, 1992)
🔗 Physical Review D — Hawking, S. W., "Chronology protection conjecture" (1992)
🔗 Sky at Night Magazine — How Time Dilation Affects ISS Astronauts
🔗 PMC/NCBI — NASA Twins Study: Effects of Long-Duration Spaceflight
🔗 Hibridosyelectricos.com — Advances and challenges of the Alcubierre curvature motor
🔗 Meer — The Grandfather Paradox, Origin and Physical Explanation
A popular science article for information purposes. The theories described—wormholes, curvature motors, and closed time curves—correspond to mathematical models valid within general relativity, but none have been experimentally verified as of the date of this publication.
An AI that "talks cellular"
- by
cronywell
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🧬 🤖 SCIENCE AND TECHNOLOGY An AI that "talks cellular" This is IRIS, the model that deciphers the code of signals with which cells decide which tissue to become Fuente: National Geographic España · Estudio original: Nature Methods (Whitehead Institute / MIT) ⏱️ Estimated reading time: 8 minutes 📅 September 2026 |
🔬 AI & HEALTH
An AI that "talks cellular": this is how it predicts which tissue each cell will become
A team at the MIT-affiliated Whitehead Institute has developed IRIS, an artificial intelligence model capable of decoding the chemical language with which cells communicate during embryonic development. By analyzing a cell's gene activity, the system can reconstruct what signals it received and predict exactly which specific tissue — heart, lung, gut, muscle, or spinal cord — it will eventually become, according to National Geographic. The finding, published in Nature Methods, opens the door to large-scale mapping of how a body is built, cell by cell.
🖼️ View image: Human embryonic stem cells — Wikimedia Commons (Public domain/CC, Wikimedia Commons)
🗣️ The secret language of cells
When an embryo begins to develop from a small group of stem cells, these cells, which are in principle identical and have no defined function, begin to specialize: some will become neurons, others liver cells, others muscle fibers. That decision depends not on an isolated internal plan, but on an ongoing conversation: the cells send and receive chemical signals to and from their neighbors, which tell them where they are in the embryo, what stage of development they are in, and what they should become.
These messages travel through multi-step sequences called signaling pathways, authentic biochemical circuits that translate an external stimulus into very specific changes in genetic activity within the cell. Reconstructing this sequence of instructions – what signals a cell was exposed to and at what time – would allow us to understand in depth how tissues are formed and why, when this process fails, diseases appear.
The problem is that, until now, this reconstruction seemed almost impossible to scale. Science assumed that the effects of each signaling pathway varied greatly from one cell type to another, which forced each pathway to be mapped separately in each cell type: a very slow experimental work and, in practice, unmanageable for the whole of an organism.
🧩 The finding: a "fingerprint" common to all cells
The team led by Pulin Li, a researcher at the Whitehead Institute for Biomedical Research and professor of biology at MIT, along with graduate student Nicholas Hutchins, discovered something that changes the picture: each signaling pathway leaves a characteristic fingerprint, a distinctive pattern of genetic activity that reflects the specific signals that the cell received.
The decisive thing is that this fingerprint remains consistent between different cell types for the same signaling pathway. In other words, instead of mapping pathway by pathway and cell type by cell type, scientists can reconstruct the signaling history of many different cells from those shared fingerprints.
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"Think of speech recognition systems like Siri, which are trained primarily in English, but then use that training to recognize other languages. This is called transfer learning, and it's why IRIS can work on many different cell types." " — Pulin Li, Whitehead Institute / MIT |
⚙️ How IRIS works
IRIS is a neural network-based model: an artificial intelligence system designed to recognize patterns in complex data, similar to how the human brain detects regularities. The program examines a cell's overall gene activity and, from it, estimates which signaling pathways were active—"turned on"—at different points in development.
To train it, Li and Hutchins used an extensive experimental dataset that recorded how thousands of human embryonic stem cells responded to dozens of combinations of six major signaling pathways, at multiple stages of development. The result was a detailed atlas of how signal combinations shape cell behavior.
Then came the litmus test: The researchers applied IRIS to individual cells from mouse embryos during gastrulation, the stage when cells rapidly branch out to very different destinations. The model predicted precisely when and where certain signaling pathways would be activated in cells destined to be part of the heart, gut, muscle, and spinal cord.
|
Target Tissue |
Stage evaluated |
IRIS Result |
|
Heart |
Gastrulation (mouse embryo) |
Accurate prediction of the time and place of signal activation |
|
Intestine |
Gastrulation (mouse embryo) |
Accurate prediction of the time and place of signal activation |
|
Muscle |
Gastrulation (mouse embryo) |
Accurate prediction of the time and place of signal activation |
|
Spinal cord |
Gastrulation (mouse embryo) |
Accurate prediction of the time and place of signal activation |
|
Lung tissue |
Signaling pathway design to induce destiny |
Experimentally Confirmed in Mouse Embryos |
🖼️ View image: Embryonic gastrulation scheme — Wikimedia Commons (Pidalka44, Wikimedia Commons)
🫁 From Prediction to Lung: The Ultimate Test
The most telling experiment came when the team used IRIS to identify which signals would be needed to generate a key cell type in lung development. The model predicted that activating a specific signaling pathway would favor development into lung tissue. The researchers tested that prediction in mouse embryos, and the experimental results confirmed it.
By accurately identifying the signal combinations that drive lung cell development, the team can more reliably generate laboratory models—organoids, miniature three-dimensional structures that mimic real organs—that faithfully reproduce human lung tissue.
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"In these ways, IRIS is helping us decode the language that cells use to talk to each other, at a much faster speed than we could actually achieve through experiments. " — Nicholas Hutchins, Whitehead Institute |
💊 Why this matters for medicine
The finding, published in the journal Nature Methods, has very concrete implications beyond the developmental biology lab. Once scientists identify the pattern of signals that pushes a stem cell to become a specific cell type, they can artificially recreate those signals to direct the fate of stem cells in laboratory or clinical contexts.
Among the applications that the team highlights are:
• Engineering stem cells for regenerative medicine, guiding their differentiation towards the desired cell type with greater efficiency.
• More precise organoids, that is, three-dimensional models of organs used to study diseases and test drugs before reaching clinical trials.
• Models of lung diseases such as asthma, lung cancer, and pulmonary fibrosis, in which tissue scars often with no known cause.
• Design of regenerative treatments capable, in the future, of repairing damaged lung tissue.
The team notes that these improved models would allow not only a better understanding of why these diseases develop, but also use them as a testing platform for new therapies, with the ultimate goal of designing real regenerative treatments.
🌐 A field in full swing
IRIS joins a recent wave of artificial intelligence models that attempt, each from a different angle, to "read" cell behavior. In early 2026, researchers at Columbia University presented a method capable of accurately predicting gene activity within any human cell from gene expression data from millions of cells in normal tissues, also published in Nature.
Months later, an international consortium made up of the Stowers Institute for Medical Research, Helmholtz Munich, the Technical University of Munich and the University of Oxford presented RegVelo, an AI framework that simultaneously models cell dynamics and gene regulation to predict how cells make decisions about their fate, experimentally validated in zebrafish.
At the same time, other research teams have been developing models such as Sig2Fate, aimed at decoding cell fate from a snapshot of combinatorial signaling in human gastruloids. The common denominator of all this work is the same ambition: to turn traditionally descriptive developmental biology into a science capable of predicting in advance how a cell will behave in the face of a given stimulus.
Specialists in the intersection between artificial intelligence and biology, such as Microsoft researcher Ava Amini, have warned, however, that the path is not without obstacles: several existing models of cellular AI tend to predict only average values rather than actual biological differences, and their performance does not always improve with increasing volume of training data. IRIS, by relying on shared signaling fingerprints between cell types rather than exhaustive mapping, proposes a different way to get around this limitation.
❔ Frequently Asked Questions
❓ What exactly is IRIS?
It is an artificial intelligence model based on neural networks, developed at the Whitehead Institute (affiliated with MIT), which analyzes the gene activity of a cell to estimate which signaling pathways it received and at what point in development.
❓ How does IRIS predict which tissue a cell will become into?
The model detects "fingerprints" of genetic activity specific to each signaling pathway, which remain stable between different cell types. From these fingerprints, it reconstructs the history of signals that the cell received and, with this, predicts its tissue fate: heart, intestine, muscle, spinal cord or lung, among others.
❓ Where and when was the study published?
The results were published in the journal Nature Methods on September 8, 2026, in a study led by Pulin Li and Nicholas Hutchins, from the Whitehead Institute for Biomedical Research.
❓ What is the use of this advance in practice?
It allows for more precise design of protocols to guide stem cells to a desired cell type in the laboratory, improve the manufacture of organoids to study diseases such as asthma, lung cancer or pulmonary fibrosis, and lay the foundations for future regenerative treatments.
❓ Is it the first AI to try to decipher cellular fate?
No. It joins other recent developments, such as a Columbia University model for predicting cell gene activity and RegVelo, a framework developed by institutions such as the Stowers Institute, Helmholtz Munich, and the University of Oxford. What's new about IRIS is its ability to generalize between cell types through transfer learning.
🔮 What's next
The Whitehead Institute team says this approach opens up the possibility of comprehensively mapping the signaling histories of every cell within a mouse or human embryo on a scale that was previously unattainable. If that mapping comes to fruition, the promise is twofold: to understand in unprecedented detail how a handful of undifferentiated cells build an entire body, and to learn how to guide that process from the lab to repair what the disease breaks.
Ultrasound-cooled notebooks
- by
cronywell
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🔊 TECHNOLOGY · IFA BERLIN 2026 Ultrasound-cooled notebooks How AirJet solid-state chips, with membranes that vibrate at ultrasonic frequencies, are starting to replace traditional fans 🗓️ September 2026 ⏱️ Reading Time: 9 minutes midire.ar |
In the halls of IFA Berlin 2026, the most important consumer electronics fair in Europe, one of the most repeated findings of the specialized media had nothing to do with a brighter screen or a faster processor, but with something that is not seen: the system that keeps the computer cool from the inside. Several manufacturers, with Lenovo at the forefront, exhibited notebooks that completely dispense with traditional mechanical fans and instead use solid-state chips that expel air through membranes that vibrate at ultrasonic frequencies.
The technology is not a laboratory promise: it is called AirJet, it has been developed by the American firm Frore Systems since 2019 and has already been perfected for several generations. What changed in 2026 is that it stopped being a fair demonstration to begin to be integrated into real notebook concepts, with their own names and a date of approach to the market.
🖥️ What was shown at IFA 2026
Lenovo brought two prototypes to Berlin that illustrate where this technology is headed. The most talked-about one, presented under the name "Project AeroBlade" (also referred to in the fair's coverage as ThinkBook Aero), is a notebook weighing less than 830 grams and less than 10 millimeters thick that has absolutely no ventilation grille or conventional fan.
Inside, Lenovo installed four AirJet Mini modules from Frore Systems, each just 2.65 millimeters thick, which are responsible for extracting the heat generated by the processor. As explained by the company itself, this solid-state active cooling architecture – commercially called "Active Flow" – allows the performance of artificial intelligence workloads to be sustained, reduces noise to almost imperceptible levels and eliminates the entry of dust that traditionally enters through the grilles of conventional equipment.
• Less space, less weight: By not needing the volume of a centrifugal fan or its intake grilles, Lenovo was able to reduce the size of the motherboard and, consequently, the entire chassis of the computer.
• Direct collaboration with Frore Systems: Lenovo did not buy a generic component, but developed the thermal design together with the company that invented the technology, something that anticipates a deeper integration in the future.
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"Lenovo put this laptop on a diet: it has absolutely no vent or traditional fan." — Specialized coverage of the Lenovo ThinkBook Aero at IFA 2026 |
🔬 How Ultrasonic Cooling Really Works
Despite the name "ultrasound," the technology has nothing to do with cleaning jewelry or ultrasound: it relies on the piezoelectric effect, the same physical principle that allows a quartz crystal to modulate the frequency in a watch or an inkjet printhead to shoot microscopic droplets with complete precision.
Inside each AirJet chip is a set of microelectromechanical structures (MEMS) that include ultra-thin membranes. When an electric current is applied to them, these membranes vibrate at ultrasonic frequencies — above the range audible to the human ear — with displacements of just tens of microns. This repetitive motion turns each membrane into a kind of miniature suction and ejection pump.
• Cold air suction: The vibration generates a strong depression that draws ambient air through inlet holes located on the top of the chip.
• High-speed pulsating jets: this air is then expelled in the form of microjets that reach speeds close to 200 kilometers per hour, directly impacting a copper heatsink in contact with the processor.
• Ten-fold higher return pressure: According to data from Frore Systems, an AirJet module can generate up to 1,750 pascals of back pressure, about ten times more than a conventional mechanical fan, allowing it to force air through even through heatsinks with fins close together, something that a traditional fan does not achieve efficiently.
• Hot air outwards: finally, this air, already charged with heat, is expelled from the computer through a small exhaust duct, without the need for the large grilles that are usually seen on the sides of a conventional notebook.
With no moving parts such as a rotor or blades, Frore Systems describes AirJet as a "solid-state" cooling system: there are no bearings to wear out, there is no mechanical vibration and, because it does not require large openings for air intake, the assembly can be sealed with filters that directly block dust ingress, something that in traditional fan equipment is one of the main causes of thermal degradation over time.
📊 Traditional fan vs. AirJet: the comparison
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Feature |
Traditional fan |
Chip AirJet (Frore Systems) |
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Moving parts |
Rotor and blades |
None (solid state) |
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Typical thickness |
8-12 mm or more |
2.65 mm per module |
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High Load Noise |
Up to 40+ dBA |
21-24 dBA per module |
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Dust resistance |
Low (open grids) |
Alta (sellable, IP53-IP68) |
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Generated back pressure |
Reference (1x) |
Up to 10 times larger |
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Scalability |
One fan per zone |
Multiple Combinable Chips |
🌐 It's not the only bet: the solid-state cooling landscape
Frore Systems is, so far, the company with the largest commercial deployment in this category – its technology has already been seen before in Zotac mini PCs, in high-performance SSD storage accessories and in Qualcomm reference platforms – but it is not alone. Different firms are exploring variants of the same concept of "air without moving parts": some, such as xMEMS, are betting on piezoelectric membranes built directly on silicon; others are moving forward with ionic wind technologies based on electrical discharges (known as EHD or DBD plasma), which move air without any mechanical vibration.
That expanding ecosystem suggests that 2026 could be remembered as the year solid-state cooling ceased to be a fairground curiosity and began to become a real alternative for a portion of the market for ultra-thin notebooks and edge AI devices, which need to sustain constant processing loads without being able to resort to a thick chassis or a noisy fan.
⚡ Why this matters right now
The interest in these solutions is not accidental: it coincides with the rise of Copilot+ PCs and notebooks aimed at artificial intelligence, which integrate processors capable of running models locally and that, therefore, generate sustained heat peaks very different from those of a traditional office notebook. When a processor overheats, the chip itself automatically reduces its speed to protect itself – the phenomenon known as thermal throttling – which ends up directly hitting the performance that the user perceives.
For manufacturers, moreover, the promise of a fanless system opens the door to thinner and lighter designs without sacrificing power, something that until now used to be solved by limiting the performance of the processor in ultra-thin computers. It is, in short, the same tension that ultra-thin notebooks with passive cooling face today: to remain silent and compact, but without that meaning giving up performance under sustained load.
🧩 The challenges that still lie ahead
• Cooling scale: Each AirJet Mini module removes a few watts of heat, so high-performance teams need to combine multiple chips in parallel, impacting the total cost of the system.
• Manufacturing cost: As these are components made with lithography processes similar to those of a silicon chip, their cost per unit is still higher than that of a conventional mass-produced mechanical ventilator.
• Actual adoption in final products: much of what was shown at IFA 2026, such as Lenovo, still corresponds to prototypes or "concepts", not to models that are already on sale in stores.
📈 Technology, in numbers
|
Indicator |
Fact |
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AirJet Public Launch Year |
2023 (CES) |
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Thickness of an AirJet Mini module |
2.65-2.8 mm |
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Weight of an AirJet Mini module |
~11 grams |
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Generated back pressure |
Up to 1,750 pascals |
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Speed of micro air jets |
~200 km/h |
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Noise level of a module |
21-24 dBA |
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Weight of the Lenovo Project AeroBlade prototype |
< 830 grams |
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Grosor del prototipo Lenovo Project AeroBlade |
< 10 mm |
❓ Frequently Asked Questions
❓ What exactly is ultrasonic cooling in notebooks?
It's a solid-state cooling system, like Frore Systems' AirJet, that uses microelectromechanical membranes that vibrate at ultrasonic frequencies to generate jets of air, replacing the traditional mechanical fan.
❓ Does the notebook with this system make any noise?
Yes, but much lower than a conventional fan: AirJet modules operate between 21 and 24 decibels, compared to the more than 40 decibels that a traditional fan can reach under high load.
❓ Which brands showcased this technology at IFA 2026?
Lenovo was the most prominent, with the Project AeroBlade (fanless, using AirJet) and Project Swan concept prototypes, although Frore Systems' technology had already been integrated into other devices since 2023.
❓ Can you buy a notebook with ultrasonic cooling now?
The models shown at IFA 2026 are mostly concept prototypes; AirJet technology is commercially available in some mini PCs, storage accessories and reference platforms from 2023.
🖼️ Reference Images
The following images, available on Wikimedia Commons under free licenses, illustrate the context of the fair and the traditional refrigeration system that this technology seeks to replace:
🖼️ South entrance of the Messe Berlin exhibition centre during IFA 2018, the usual venue of the fair: commons.wikimedia.org/wiki/File:IFA_2018_%E2%80%93_hlavn%C3%AD_vstup_jih.jpg
🖼️ Operating diagram of a traditional notebook cooling system, with fan and heatpipes: commons.wikimedia.org/wiki/File:Diagram_-_How_a_laptop_cooling_system_works.png
🖼️ Heatsink and fan assembly typical of a previous generation notebook: commons.wikimedia.org/wiki/File:Laptop_Heatsink.jpg
🚀 THE "LAST DANCE" OF CLUSTER SATELLITES
- by
cronywell
Tango re-entered the Pacific and turned its destruction into a scientific laboratory
September 2, 2026 · Space Science · Space Security · Space Debris
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SEO Title |
Cluster's last dance: Tango re-entered over the Pacific and was observed from an airplane |
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Meta Description |
ESA completed the controlled re-entry of Tango, the last satellite of Cluster II. The ROSIE scientific flight recorded its destruction to improve space security. |
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Suggested Slug |
last-dance-satellites-cluster-tango-re-entry-controlled |
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Primary Keyword |
Tango satellite controlled re-entry |
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Keywords secundarias |
ESA, Cluster II, space debris, atmospheric reentry, ROSIE, Zero Debris, design for destruction |
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Reading Time |
≈ 8 minutes |
🌎 The end of a historic mission did not simply end with a satellite falling to Earth. On September 1, 2026, Tango – the fourth and last member of the Cluster II constellation – deliberately re-entered over a remote region of the South Pacific. The European Space Agency (ESA) also managed to observe the phenomenon from an aircraft equipped with a battery of scientific instruments. The goal: to transform the destruction of a spacecraft into useful data to design safer and more sustainable missions.
The manoeuvre closed a chapter of 26 years of Cluster activity and consolidated a strategy that ESA considers key to orbital sustainability: planning for the end of life of satellites with as much precision as their launch and operation. The campaign also made it possible to study in real conditions how a spacecraft heats up, fragments and disappears as it passes through the atmosphere. cite no — source integrated below
🔥 Tango: a planned farewell to the second
Tango (Cluster II FM-8) re-entered the Earth's atmosphere on 1 September 2026 at 21:30:31 UTC, equivalent to 23:30:31 CEST. It was the last of the four Cluster satellites to complete its re-entry. The accuracy achieved allowed the observation aircraft to take off from Tonga and reach the planned area of the South Pacific to record the event.
The operation was not an accidental crash. ESA had prepared a "directed re-entry" trajectory to take the satellite to a remote and sparsely populated ocean area. The aim was to reduce the risk on land while creating the conditions for exceptional scientific observation.
The ROSIE campaign managed to observe both Samba and Tango using 29 of the 30 instruments installed on board the aircraft. Scientists were able to follow each re-entry for about 50 seconds on average. In the case of Tango, even the pilot's maneuver contributed to keeping the satellite in the field of view for a few additional seconds.
🛰️ Cluster: 26 years looking at Earth's magnetic heart
Cluster was born to answer a fundamental question: how do the solar wind and the Earth's magnetosphere interact? The constellation was made up of four identical spacecraft—Rumba, Salsa, Samba, and Tango—that flew in formation to obtain three-dimensional measurements of the magnetic and plasma regions near our planet.
The four vehicles were launched in two pairs, on July 16 and August 9, 2000. Although its nominal operational life was only two years, the mission was repeatedly extended and ended up becoming one of the great veteran missions of European space science.
Each spacecraft carried 11 instruments dedicated to studying charged particles, electric fields, magnetic fields and waves. The combination of four identical platforms made it possible to simultaneously observe different points in space and reconstruct processes that a single spacecraft could not measure with the same precision.
🌞 Why was it important to study the magnetosphere?
The magnetosphere functions as a shield against the flow of particles and magnetic fields from the Sun. When the solar wind interacts with it, space weather phenomena can occur capable of affecting communications, navigation, satellites and power grids.
Cluster provided a three-dimensional perspective of processes occurring at very different scales, from small structures in the plasma to large regions of interaction between the solar wind and the Earth's magnetic environment. Its scientific legacy does not end with re-entry: the data accumulated during the mission will continue to be analyzed.
✈️ ROSIE: Turning a Destructive Re-Entry into an Experiment
The most novel part of the final chapter of Cluster was aerial observation. ROSIE—the re-entry observation campaign—brought a suite of cameras and sensors to a carefully calculated position to look at the phenomenon from below the trajectory.
A tracking camera makes it possible to determine where the object is located and how its fragmentation is evolving. Complementary cameras and sensors also look for information about the materials that appear during decay. This allows researchers to compare what actually happens with the predictions of re-entry models.
The experience with Salsa, which re-entered in September 2024, was decisive. That campaign revealed, among other things, differences of up to 20% between the predicted and observed atmospheric density, and suggested that fragmentation could begin somewhat earlier than indicated by certain models.
🌡️ What happens when a satellite enters the atmosphere?
A hypersonic re-entry subjects the vehicle to enormous aerodynamic and thermal loads. The air is violently compressed in front of the ship, the temperature rises, and the materials begin to heat, deform, melt, and vaporize. The structure loses integrity and the vehicle progressively fragments.
But the process is not as simple as "the satellite burns up." Some components can survive longer because they are protected by other parts of the structure. Dense materials or internal components can withstand even later stages of descent. That is precisely why real observations are so valuable in refining simulations.
The data from Tango and Samba complement the experiences of Salsa and Rumba and allow us to study re-entries from four similar satellites under different conditions. Controlled repetition reduces one of the great difficulties of this science: the scarcity of direct observations of the actual destruction of a spacecraft.
🌊 Why the South Pacific?
The choice of a remote area of the ocean responds to a basic safety principle: to minimise the risk to people, buildings and infrastructure. ESA adjusted the trajectories of Samba and Tango so that their re-entries would occur in a region that was sparsely populated and, at the same time, sufficiently accessible for a scientific aircraft operating from Tonga.
Orbital accuracy was especially important because the aircraft had to be in the right place, at the right time, and with the right orientation to observe a phenomenon that lasts only a few moments. The campaign combined orbital data, ground tracking, and telescopes to refine the predictions.
♻️ From "space junk" to sustainable design
Tango's re-entry has a reading that goes far beyond Cluster. Earth orbit is becoming increasingly congested and each mission must consider what will happen when its useful life ends.
ESA is promoting its "Zero Debris" approach, aimed at drastically reducing the generation of new debris in orbit and improving disposal strategies at the end of missions. Within this philosophy is the concept of "Design for Demise": designing satellites so that, during a re-entry, they disintegrate more completely and reduce the risk of components surviving to the surface.
There is also "Design for Removal", which seeks to ensure that future spacecraft incorporate interfaces and technologies that allow them to be actively removed if they cannot complete their disposal on their own. The logic is simple: the end of a mission should be part of the design from the beginning, not an improvised decision when fuel or systems are about to run out.
📊 The four finals of Cluster
|
Satellite |
Re-entry |
Result |
Scientific key |
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Sauce |
Sep 8. 2024 |
Directed re-entry |
First aerial observation campaign |
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Rumba |
Oct 22 2025 |
Directed re-entry |
Second experience and model tuning |
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Samba |
Aug 31. 2026 |
Directed re-entry |
ROSIE observation; more than 50 s of images |
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Tango |
1 Sep. 2026 |
Directed re-entry |
Last satellite; ROSIE campaign completed |
🔬 What data can change the future
The main utility of the campaign is not the spectacularity of the images, but the possibility of contrasting models with a real sequence of events. Knowing when intense heating begins, which components are separated first, which materials survive and how the fragments are distributed allows us to improve re-entry predictions.
That knowledge can help design satellites that are more completely destroyed as they pass through the atmosphere and more accurately calculate residual risk on the surface. It can also improve the planning tools used by operators and authorities to determine when and where a mission will end.
🔭 The next step: Draco
The Cluster experience will not be the end point of the investigation. ESA is preparing Draco, a re-entry mission planned for 2027 that will seek to record the phenomenon from inside the vehicle itself. According to ESA, Draco will have more than 200 sensors, four cameras and a capsule designed to preserve data during destruction.
The aim will be to complement external observations made from aircraft with an internal perspective: to measure exactly what happens to the structure and its components as the vehicle goes through the different stages of re-entry.
🧭 An ending that is also a warning
Tango's "last dance" sums up a transformation in the way we think about space missions. For decades, success was measured primarily by launch, scientific operation, and the amount of data obtained. Today there is a fourth inseparable dimension: how the mission ends.
Cluster showed that even the end of a veteran satellite can become science. Its four targeted re-entries show that safely retiring a spacecraft doesn't have to mean simply losing it: it can mean generating knowledge that reduces the risks of future generations of satellites.
Tango disappeared into the atmosphere, but its last journey left something that doesn't burn: data. And that data can help keep near-Earth space usable, safe, and sustainable.
📷 Official Images and Resources for the Article
The following official ESA pages contain the recommended images and audio-visual materials. They are included as absolute links for web publication and attribution:
Tango’s reentry recorded — ESA/ROSIE/University of Stuttgart (HEFDiG) · https://www.esa.int/ESA_Multimedia/Images/2026/09/Tango_s_reentry_recorded
Samba’s reentry recorded — ESA/ROSIE/University of Stuttgart (HEFDiG) · https://www.esa.int/ESA_Multimedia/Images/2026/09/Samba_s_reentry_recorded
Cluster II reentry ground tracks: Samba and Tango — ESA · https://www.esa.int/ESA_Multimedia/Images/2026/08/Cluster_II_reentry_ground_tracks_Samba_and_Tango
ROSIE: Cluster’s Samba and Tango Re-entry Observation Campaign — ESA Television · https://www.esa.int/esatv/Videos/2026/08/ROSIE_Cluster_s_Samba_and_Tango_Re-entry_Observation_Campaign
🔗 Sources and references
ESA — Cluster’s encore for reentry science a success (2 sep. 2026)
ESA — Samba’s fiery farewell recorded (1 sep. 2026)
ESA — Observing Samba and Tango’s reentries (28 ago. 2026)
ESA — Zero Debris technologies
© 2026 · Article prepared for editorial blog publication · Research based mainly on official ESA sources