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VLM writes:

For about a century, quantum mechanics, QM, has required the use of complex numbers, but according to a recently published peer reviewed paper in PRL, given a large amount of mathematical fooling around, it's possible to do QM solely with real numbers. That's very unexpected and very cool and the future is going to be very interesting!

https://arxiv.org/abs/2503.17307

https://journals.aps.org/prl/abstract/10.1103/4k13-sdjh

There's been an effort in recent years to formulate quantum mechanics without complex numbers, slowly chipping away at existing QM theory. This paper solves the last remaining problem, and now AFAIK the entire QM system works, or is compatible, or at least not disproven yet, when doing QM calcs using only real number space. The conclusion of the abstract kind of says it all "Thus, we argue that real-valued quantum mechanics cannot be falsified, and therefore the use of complex numbers is a matter of convenience."

I read, or tried to read the paper, back in March last year when the free preprint was uploaded to arxiv and I see it successfully made it through peer review and was published in PRL three weeks ago. AFAIK, nobody has successfully shot it down in the last three weeks, so this interesting project is likely to be successfully completed. Apparently, they have done it!

Effects:

This is one of those accomplishments like when a century ago they proved 1+1=2 solely using set theory. That specific example is not immediately useful, a century later, and note that set theory accomplishment from the 1910s is still pretty useless IRL, but the point of the effort was that they successfully connected two "very large theories" that were not supposed to be connectable. It's not supposed to be possible to QM without complex numbers. A somewhat more famous and wildly profitable theory unification would be when the separate theory of electrical fields and theory of magnetic fields were connected (see Maxwell, etc) I'd say the theory of electromagnetism has had quite an effect on the world since it was discovered... The accomplishment in the paper will probably has an impact in between the two examples above.

Trivially, textbooks will need to be updated such that QM does not have a mandatory inherent requirement for complex numbers, although the formulation is simpler if you use them. Sort of like you don't have to use logarithms to multiply numbers, but it sure is easier to manufacture slide rules if you use logarithms to multiply numbers...

I always found it philosophically distasteful that the most accurate model we have for subatomic particles IRL, requires imaginary sqrt(-1) math. It only took a century to prove it does not. The main paper itself is only about five pages and seems pretty clear, its the dozen page long appendix thats mathematically a bit of a beast to get thru.

There will probably be an unpredictable effect on unification theories. I'd sure be excited to hear a news story in a year or two about some dude who has been sitting on an experimental pet string theory or loop quantum gravity or some other misc theory for years (decades?) that would unify gravity and QM into one theory that "was obviously wrong because it required a QM expressible without complex numbers" well its 2026 and we got one of those now, so really big things might happen really soon. Or maybe not.

Original Submission

Arthur T Knackerbracket writes:

A new dental robot is being developed that could reduce the number of visits needed to receive a dental crown:

A new dental robot is in development at the University of Basel in Switzerland to help with tooth drilling. It's called the MIR, or Miniature Intraoral Robot, and its bite-sized design allows it to fit inside a patient's mouth.

The aim is to speed up the process of fitting a new crown when tooth decay is discovered. Today, a patient with tooth decay needs multiple follow-up appointments to prepare the tooth for the new crown, including fitting a temporary crown. With the MIR, a dentist could scan the patient's mouth and order a new crown during the first appointment, reducing the number of visits required.

The robot's larger components, including the motor and controls, are kept outside the mouth and connected to the robot via cables and a drive shaft. It's similar to the process used in cars to transfer motion from the motor to the wheels.

The dental robot attaches directly to the patient's teeth.

The robot is mounted to a custom-fitted dental splint, which attaches to the teeth. If the patient moves their head, the robot moves with it.

So far it's been tested on fake ceramic teeth in a fake patient's mouth but it's not yet ready to be used on a human. The team plans to add sensors and a camera so the robot can keep track of its position, even during a power outage.

To see the robot in action, check out the video in this article.

Original Submission

Arthur T Knackerbracket writes:

A final humiliation for Australia's Securities Exchange and its attempts to run a bourse on distributed ledgers:

The attempt by Australia's Securities Exchange (ASX) to replace its core trading platform with a blockchain-based system has ended with an A$20.5 million fine ($14.2 million/£10.6 million), further humiliation after the project flopped.

The ASX runs a platform called the Clearing House Electronic Subregister System (CHESS) to process and track trades on its exchange. In 2017, the ASX decided to replace CHESS, citing difficulties maintaining the application, which the bourse coded in COBOL and ran in OpenVMS on Itanium processors.

The ASX is a listed company so its own shares trade on CHESS.

The organization decided to replace CHESS with blockchain-based architecture. As explained in its 2019 annual report [PDF], the ASX believed its decision would help it "develop new services that improve the efficiency and standardisation of processes, reduce operational risk, and create new opportunities for growth and innovation."

That optimism was utterly misplaced because the project foundered and missed deadline after deadline.

But in February 2022, the ASX issued a statement [PDF] in which it described the project as "progressing well, with the fully integrated industry test environment open and operating successfully."

In the months that followed, the organization issued a string of statements about difficulties with the project and expected deployment delays. The ASX ended up abandoning the project.

In 2024, financial regulator the Australian Securities and Investments Commission (ASIC) sued, alleging that claim all was well with the CHESS replacement was a misleading statement. The regulator argued that as both the market operator, and a listed company itself, any misleading statements from ASX had the potential to undermine confidence in the entire Australian securities market.

ASX and ASIC settled the matter in June, and the bourse admitted [PDF] to having misled investors.

Arthur T Knackerbracket writes:

The agency is giving autonomous vehicle makers until the end of July to figure out a solution:

The US Department of Transportation's National Highway Traffic Safety Administration (NHTSA) is demanding action from autonomous car makers after identifying "a clear pattern of driverless AVs interfering with law enforcement and other first responders" over the past months. Jonathan Morrison, the agency's administrator, wrote a letter addressing the developers and issuing a call to action. Emergency situations are not rare or "edge cases," he wrote, so he wants AV developers and operators focus their resources on fixing the issue immediately.

While the NHTSA didn't give specific examples, there have been news about self-driving vehicles getting in the way of ambulances and fire trucks, like in the image above, for years. After a deadly shooting at a bar in Austin, Texas in March, a Waymo vehicle blocked an ambulance that was responding to the incident. While an officer was able to manually drive the Waymo robotaxi out of the way, it cost them a few minutes to resolve the problem.

According to Wired, emergency first responder leaders told regulators during a meeting in March that they were becoming frustrated at the behavior of autonomous vehicles on the streets. They said they've had to spend time during emergencies resolving problems with frozen or stuck cars. Officials from San Francisco and Austin, where Waymo's robotaxi service has been in operation for a while now, said the company's vehicles have been getting worse. They've apparently been seeing "backsliding" in the AVs' performance, with the vehicles now committing more traffic violations.

Arthur T Knackerbracket writes:

Doctors find grey fluid and dead, metallic flesh inside poisoned woman's hip:

A 56-year-old woman was admitted to a hospital with an array of alarming symptoms that were only getting worse. For eight weeks, she had a painful "pins and needles" feeling that started in both of her feet and then began working its way up her legs. By the time she arrived at the hospital, she was unable to feel her feet on the ground. She frequently stumbled and clutched at walls to stay up. But the tingling numbness was moving into her hands, too. Then came neurological symptoms. She told her doctors about short-term memory problems and difficulty concentrating. She was irritable and had no appetite. She was experiencing heart palpitations, too.

According to a case report this week in the New England Journal of Medicine, her doctors looked through her medical history for clues, finding nothing that immediately stood out. She had high blood pressure, a history of anxiety and depression, and hypothyroidism (an underactive thyroid). They did notice that, although she had managed the thyroid problem for more than a decade at the same dose of medication, she had been switched four weeks earlier to a stronger dose. But the dosage change didn't immediately raise any red flags.

She also had a history of hip problems. Twenty years before, she had a hip replacement that stemmed from an injury she sustained in a car crash ten years before that. While more than 90 percent of hip replacements last at least 30 years, the woman's started failing her after 19.

The year before her current condition, the hip prosthesis had become dislocated. At the time, doctors were able to put it back into position without surgery, but she continued to have pain and problems walking. Imaging also indicated that the lining in the hip socket was failing. So about three months before her alarming symptoms developed, she had surgery at a different medical facility to replace parts of her artificial hip joint, a surgery described as a hip "revision."

[...] At that point, the records from her hip revision came in. The report clarified that 20 years ago, the woman had received a titanium and ceramic hip joint. Specifically, the joint included a titanium shell (acetabular shell) that fit into the hip bone, a ceramic liner in that shell, then a ceramic ball (femoral head) on the top of a titanium stem (femoral stem) that extended into her thigh bone (femur). Over time, the ceramic liner in the acetabular shell shattered, and the ceramic femoral head began directly moving against the titanium shell.

During the hip revision, a surgical team replaced the destroyed ceramic liner with one made of polyethylene. They also replaced the ceramic femoral head with a cobalt–chromium alloy one. The original titanium acetabular shell and femoral stem were kept in place. The report noted that the team had to do extensive cleaning of the woman's hip to try to clear out all the fragments of the wrecked ceramic liner that had scattered in the joint and surrounding tissue.

After seeing the report, the woman's doctors immediately understood the problem: She had severe cobalt poisoning.

mrpg writes:

https://www.science.org/content/article/key-arctic-science-outpost-finds-itself-tangled-geopolitical-web

[...] The tensions stymieing the UNIS geologists reflect broader changes unfolding across Svalbard, a jagged, ice-cloaked archipelago consisting of nine larger islands and thousands of islets perched between mainland Europe and the North Pole. For centuries the islands, encompassing an area roughly the size of Latvia, were a no-man's land, inhabited mainly by reindeer and polar bears whose ancestors arrived on drifting pack ice. Today, Svalbard has fewer than 3000 human residents but is home to scientific facilities operated by more than a dozen countries, including China, India, and Russia. Many are clustered at Ny-Ålesund, a research outpost on the largest island, Spitsbergen, that Norway promotes as a symbol of collaborative Arctic science.

Researchers have long journeyed to Svalbard to study everything from glaciers to the northern lights. But in recent years the archipelago has become especially important to science because it provides a front-row seat to some of the fastest warming on Earth; since 1991 the region's mean annual air temperatures have risen at roughly seven times the global rate—and twice the Arctic average.

Even as climate change boosts Svalbard's scientific value, however, rising geopolitical tensions in the Arctic are making research more difficult. In its National Threat Assessment for this year, Norway's Police Security Service warned that Svalbard is "especially exposed" to Russian spying, and that "China will try to use research as a gateway to Norwegian territory in the High North."

Original Submission

Arthur T Knackerbracket writes:

Modula-based source code resurfaces after nearly four decades:

For the first time, the source code of KSOS, backed by the US Department of Defense in the late 1970s and 1980s, is available to the public in the archives of The Unix Heritage Society (TUHS).

TUHS volunteers preserve the historical source code and documentation of the original UNIX – or as much of it as is left. A few days ago, in an email to its mailing list, TUHS founder Warren Toomey announced the addition of KSOS to the collection.

"KSOS was the US Department of Defense (DoD) Kernelized Secure Operating System (KSOS, formerly called Secure UNIX). KSOS is intended to provide a provably secure operating system for larger minicomputers," he wrote.

Despite its age, KSOS sounds surprisingly modern. It was a Unix-compatible OS, implemented in a type-safe programming language, Modula, rather than C. Modula was the late great Niklaus Wirth's successor to Pascal and, in turn, the forerunner to Modula-2 – which we described when it was added to the GNU Compiler Collection in 2022. KSOS was designed to be formally verifiable, so that it could be trusted for use in highly secure systems. It ran on commodity hardware, and its development was sponsored by the US DOD.

Very few OS kernels have been formally verified, and one of the best-known modern examples is the seL4 microkernel, as used in the Ironclad OS we covered last year, and also in the new QSOE RISC-V RTOS. KSOS isn't some cutting-edge experimental new Rust effort, like the Asterinas project we described last year or the even newer Maestro project.

What became KSOS started in 1978 at Ford Aerospace (yes, that Ford). On the team were Peter Neumann, who later ran the RISKS Digest – The Register was quoting him in 2004 – and Tom Perrine, who described it and its modern relevance in a 2002 article for the USENIX journal ;login:. It's titled "The Kernelized Secure Operating system (KSOS)" [PDF], and at only three and a bit pages long, it's well worth a read. Even then, 24 years ago, projects were struggling to reinvent things KSOS did successfully a couple of decades earlier. That's even more true today. To learn more about how KSOS worked, there's a 1978 Executive Summary [PDF] – which, despite its title, runs to 15 pages. Clearly, executives back then had longer attention spans.

Perrine gave a talk about KSOS at DEF CON 20 in 2012, which you can watch on YouTube.

"mrpg" writes:

Scientists discover the deep sleep circuit that builds muscle, burns fat, and boosts the brain:

A good night's sleep does far more than leave you feeling refreshed. It also triggers the release of growth hormone, a key hormone that helps build muscle and bone, burn fat, and support healthy growth. That's why athletes value quality sleep for recovery, and why teenagers need enough sleep to reach their full height potential.

Scientists have long known that growth hormone levels rise during sleep, especially during the deep, non-REM stage. What has remained unclear is exactly how the brain controls this process.

Now, researchers at the University of California, Berkeley have uncovered the brain circuitry responsible for regulating growth hormone during sleep. Their study, published in the journal Cell , also reveals a previously unknown feedback system that helps keep growth hormone levels in balance.

The discovery offers new insight into the close relationship between sleep and hormone regulation. It could eventually guide new treatments for sleep disorders linked to metabolic diseases such as diabetes, as well as neurodegenerative conditions including Parkinson's and Alzheimer's disease.

"People know that growth hormone release is tightly related to sleep, but only through drawing blood and checking growth hormone levels during sleep," said study first author Xinlu Ding, a postdoctoral fellow in UC Berkeley's Department of Neuroscience and the Helen Wills Neuroscience Institute. "We're actually directly recording neural activity in mice to see what's going on. We are providing a basic circuit to work on in the future to develop different treatments."

Because growth hormone also helps regulate glucose and fat metabolism, consistently poor sleep may increase the risk of obesity, diabetes, and cardiovascular disease.

The nerve cells that coordinate growth hormone release are located deep within the hypothalamus, an ancient brain region found across mammals. These include growth hormone-releasing hormone (GHRH) neurons, along with two different types of somatostatin neurons.

Once growth hormone is released, it activates neurons in the locus coeruleus, a brainstem region involved in alertness, attention, thinking, and responding to new experiences. Problems affecting the locus coeruleus have been linked to numerous neurological and psychiatric disorders.

"Understanding the neural circuit for growth hormone release could eventually point toward new hormonal therapies to improve sleep quality or restore normal growth hormone balance," said Daniel Silverman, a UC Berkeley postdoctoral fellow and study co-author. "There are some experimental gene therapies where you target a specific cell type. This circuit could be a novel handle to try to dial back the excitability of the locus coeruleus, which hasn't been talked about before."

Freeman writes:

https://arstechnica.com/ai/2026/07/we-cannot-choose-to-become-idiots-the-ai-cheating-scandal-roiling-brown-university/

Ivy League college students are, by definition, intelligent. They don't need to use generative AI to cheat on exams; they could just learn the material. But they also tend to be competitive, ambitious, and overscheduled, so AI can look like an easy shortcut that makes more time in their lives for things that can't be done by a chatbot.
[...]
A recent survey of Princeton students found that 29.9 percent admitted to cheating with AI on at least one exam or assignment.
[...]
In just the last week, Serrano—who was born in Spain—has told his story to El País and Inside Higher Ed, which have both run significant pieces on the scandal.

The story that Serrano told them begins in December 2025, when a gunman attacked Brown's campus and killed two people
[...]
Shaken by the experience, Serrano decided that his spring 2026 section of the quite difficult ECON 1170 would allow take-home exams for both the midterm and the final. Suddenly, the course received an influx of students.
[...]
"Historically the average grade in the midterm of this course has ranged between 65 and 80 [percent], and this exam was harder than the exams I wrote in the past, because... take-home is an opportunity to challenge the class a little bit more, given that you're giving the students unlimited time."

Beyond the numbers, many of the answers, even when correct, felt slightly off. They had a "very convoluted style," Serrano said. When he and his grad students ran the exam questions through ChatGPT, they received similar results.
[...]
He emailed his class, telling them, "I am not declaring [the midterm] void for now. I am going to give the class a chance to prove me wrong. That is, if the distribution of the final exam is roughly similar to the distribution of the midterm, I will count the midterm. Otherwise, which is of course what I expect to happen, I will declare the midterm void and reweigh the final accordingly."

Eighteen students suddenly dropped the course, while nine others didn't even attend the final exam. Of those 27 students, El País noted, "22 had scored a perfect 100 in the midterm exam."

Rich writes:

Chip maker Qualcomm has announced it will acquire software company Modular for $3.9bn in an all share transaction. (https://www.qualcomm.com/news/releases/2026/06/qualcomm-to-acquire-modular) Modular was founded by Chris Lattner, who is best known for the LLVM compiler backend and the invention of the Swift language from Apple. Modular develops a new language called "Mojo", which looks like Python, provides safety guarantees like Rust, and compiles down to highly efficient code to utilize massive parallelism. Mojo targets not only classic CPUs, but can also generate GPU shaders, to cover the full AI stack. It is assumed that Qualcomm will use Modular's offerings to attack Nvidia's proprietary Cuda system to gain traction in the datacenter space.

If all goes to plan, and the Qualcomm stock rises to AI bubble levels, Lattner will become the latest tech billionaire through software work alone. If not, he'll just walk away with a few hundred millions. Respect.

Original Submission

Arthur T Knackerbracket writes:

Ban lands three weeks after Anthropic accused Alibaba's Qwen lab of running the largest known distillation attack on Claude:

Employees have reportedly been instructed to adopt Qoder, Alibaba's in-house AI coding platform, as the replacement. According to reports from Chinese outlets citing company insiders, the directive reportedly goes further than Claude Code itself, as staff have allegedly been told to uninstall all Anthropic products, including the Sonnet, Opus, and Fable model families. The move is the latest escalation in a feud that ignited last month, when Anthropic accused operators linked to Alibaba's Qwen AI lab of running the largest known model distillation attack against Claude.

What elevated the discovery from routine telemetry to scandal was the exfiltration method. Rather than sending an overt signal, the tool allegedly encoded its findings steganographically, tweaking the date format and swapping a punctuation character in the system prompt sent back to Anthropic's servers — invisible to the user, but machine-parseable on Anthropic's end. The Reddit author called the covert transmission of system and proxy data "a fundamental violation of user trust," saying they simply wanted transparency from Anthropic.

Anthropic has not issued a formal statement, but Thariq Shihipar, an engineer on the Claude Code team, addressed the findings on X, describing the mechanism as "an experiment we launched in March" intended to prevent account abuse by unauthorized resellers and to protect against distillation. Shihipar said the team had been meaning to remove the code for a while, and that the pull request stripping it out was merged on July 1, the day after the Reddit post.

The timing of Alibaba’s Claude ban fits right into the wider rift between the Chinese tech giant and the U.S. artificial intelligence frontrunner. On June 10, Anthropic sent a letter to leaders of the U.S. Senate Banking Committee accusing operators affiliated with Alibaba's Qwen lab of using nearly 25,000 fraudulent accounts to generate 28.8 million exchanges with Claude between April 22 and June 5, in what it characterized as an industrial-scale attempt to distill the model's software engineering and reasoning capabilities. Distillation, training a smaller model on the outputs of a more capable one, sits in a legal and ethical gray zone that the industry has yet to resolve. Alibaba has denied wrongdoing and has not addressed the allegations in detail.

looorg writes:

https://www.windowslatest.com/2026/07/04/ex-microsoft-engineer-rebuilds-notepad-in-2-5kb-using-nothing-but-stuff-windows-already-had/
https://github.com/PlummersSoftwareLLC/TinyRetroPad

As if you needed more evidence of what is wrong with modern programming. Or scale creep in modern software. But you can still write small and efficient if you know how or want to.

Dave Plummer, the retired Microsoft engineer who built Task Manager and helped ship Space Cadet Pinball, has recreated Notepad in roughly 2.5 kilobytes.

Modern Notepad has spent the last couple of years turning into a case study in feature creep. The notepad.exe on a typical Windows 11 install comes in at around 352KB, with an install size closer to 808KB, because that exe is really a stub pointing at a UWP and WinUI app adding up to roughly 5MB on disk. The original XP-era Notepad was about 65KB in total.

While not the worst monstrosity of the current windows iteration. From 2.5k to whatever we should call modern notepad with all it's "features".

Original Submission

"mrpg" writes:

Record-breaking ocean drilling reveals why Japan's 2011 tsunami was so deadly:

Researchers have uncovered a hidden feature beneath the Pacific Ocean that helps explain why Japan's devastating 2011 earthquake and tsunami became so destructive. The discovery also offers new clues that could improve forecasts of future megaquakes and tsunamis.

A new study found that a thin layer of soft, clay-rich sediment beneath the Japan Trench played a critical role in the disaster. Located just below the seafloor, this unusually weak layer allowed the fault to rupture all the way to the trench during the 2011 "megathrust" earthquake. As a result, the seafloor shifted by an extraordinary 130 to 200 feet, helping generate the massive tsunami.

"That's equivalent to the entire area between Los Angeles and San Francisco moving 130 to 200 feet in just six minutes," said Christine Regalla, an associate professor in Northern Arizona University's School of Earth and Sustainability and a co-author of the study. "We've never seen anything like that in the time we've been observing earthquakes. Based on what we understood, we didn't think that could happen."

The research, led by Regalla and more than a dozen scientists from around the world, was published in Science .

Most large earthquakes begin much deeper below Earth's surface. Regalla explained that when tectonic plates shift, the rupture that produces an earthquake usually occurs far underground. For example, the rupture that caused the 6.8 magnitude Nisqually earthquake in the Pacific Northwest in 2001 started about 32 miles beneath the seafloor.

The 2011 Japan earthquake was very different. The rupture reached only about 15 miles below the seafloor, allowing the fault to break much closer to the ocean bottom. The resulting magnitude 9.1 earthquake triggered one of the deadliest natural disasters in modern Japanese history, killing nearly 20,000 people and causing more than $200 billion in damage.

To understand why this happened, researchers traveled to the western Pacific aboard the research vessel Chikyu . They drilled about 26,000 feet into the ocean floor, recovered sediment samples, and analyzed the material. Guinness World Records recognized the expedition as the deepest scientific ocean drilling project ever completed.

Freeman writes:

https://arstechnica.com/gaming/2026/07/bethesda-id-software-reportedly-hit-hard-by-microsoft-layoffs/

In announcing plans for 3,200 layoffs across the Xbox division yesterday, CEO Asha Sharma focused on discussing cuts to the Xbox platform team and redundant layers of middle management.
[...]
Apogee and 3D Realms founder Scott Miller—who helped publish some of id's earliest games—wrote on social media yesterday of "insider reports" that a majority of id had been laid off, "including most (if not all) coders." And last night, veteran programmer Michael Maynard—whose credits at id Software date back to 2011's Rage—wrote on LinkedIn that he was among the "roughly 50%" of the id team that was let go Monday.
[...]
Id co-founder John Romero wrote in a social media thread about his sorrow over the layoffs, saying that the people behind the current incarnation of the company "have done a great job" maintaining its legacy. "Doom, Quake, and Wolfenstein are not easy names to carry on, especially in today's industry," he wrote. "The last few games showed real care, skill and respect for what those worlds mean to people." Romero also urged Microsoft to preserve the code and documents associated with the current version of id, as Romero says he has for the incarnation he helped lead until 1996.
[...]
Meanwhile, IGN obtained an email from Bethesda President Jill Braff to staffers expressing "sincere gratitude" to "a number of our colleagues" that were impacted by the layoffs. IGN says employees at Bethesda studios were "hit particularly hard" by the layoffs, while remaining staffers are "facing an uncertain future" as Microsoft said it is planning to lay off 1,600 more employees throughout this fiscal year (in addition to 1,600 let go yesterday).
[...]
could be bad news for newer franchises like Starfield and for The Elder Scrolls Online, with the latter game losing as much as half of its developers, according to a Kotaku report.

Original Submission

A recent article in Tech Review, https://www.technologyreview.com/2026/06/12/1138833/inside-interoception-brain-body or: https://archive.is/kGwUQ
discusses new work on understanding the data that the body sends to the brain--and it's a lot more than was commonly thought...

Our senses take in information at a staggering rate—roughly 11 million bits flood in every second from our skin, eyes, ears, and more. [...] Only a sliver reaches our conscious awareness. Researchers estimate that our conscious minds can process roughly 10 to 60 bits of information per second, about the rate at which you're reading this sentence. That's a ratio of about one conscious bit to hundreds of thousands of unconscious bits.
[...]
What you are aware of: Your stomach growling when you're hungry. Your palms sweating before you speak in public. The breath you just took, if you pay attention to it. Even your heartbeat, which some people can sense from the inside without feeling their pulse in their wrist.
Scientists have a word for how we sense ourselves from the inside: interoception.

After a page or so of discussion about different signal types that are now being mapped, the article switches to developing an understanding how the sensing is done. In particular the sense of physical force or pressure--

In the 1990s, as a postdoc at the University of California, San Francisco, he [Ardem Patapoutian] became fascinated with our sense of touch—the last of the five major senses not yet understood at the molecular level. The lung stretch signal that Liberles's vagus neurons [discussed in the link] carry to the brain? No one had ever figured out how that signal began.
"How do you feel the embrace of a loved one? How do your fingers distinguish one texture of hair from another?" Patapoutian invites us to wonder in his 2021 Nobel Prize lecture. The problem: Most cellular communication works through chemistry. But mechanical force offers no molecule to bind. How does the body translate physical pressure into the electrochemical language that neurons speak?
Scientists knew that the answer had to be an ion channel—a protein gate embedded in cell membranes that opens to let electrically charged particles into the cell. But tracking down the one responsible for touch turned out to be absurdly difficult. Ion channels are a hundred thousandth the size of a cell, invisible to ordinary microscopes. Worse, they don't resemble each other. You can't recognize one by its shape or its sequence of amino acids. Even with one right in front of you, nothing would tell you it was there.
[...] Patapoutian decided to try an unusual approach. He'd try to find cells that showed sensitivity to touch and destroy their internal genetic blueprint one gene at a time—hunting for the move that would make the cell go numb. It was tedious, expensive, and possibly a dead end. "A lot of people made fun of us," he says.