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Electric sparks are used for welding, powering electronics, killing germs or for igniting the fuel in some car engines. Despite their usefulness, they are hard to control in open space, they split into chaotic branches that tend to go towards the closest metallic objects. A recent study uncovers a way of transporting electricity through air by ultrasonic waves. The level of control of the electric sparks allows to guide the spark around obstacles, or to make it hit specific spots, even into non-conductive materials.

Electric sparks are used for welding, powering electronics, killing germs or for igniting the fuel in some car engines. Despite their usefulness, they are hard to control in open space, they split into chaotic branches that tend to go towards the closest metallic objects. A recent study uncovers a way of transporting electricity through air by ultrasonic waves. The level of control of the electric sparks allows to guide the spark around obstacles, or to make it hit specific spots, even into non-conductive materials.

Researchers created platinum-mixed metallic magnetic nanofilms that are 5x more efficient -- the ultimate energy-saving solution.

A team of international researchers has developed an innovative approach to uncover the secrets of dark matter in the cosmos. They are searching for dark matter using atomic clocks and cavity-stabilized lasers.

A team of international researchers has developed an innovative approach to uncover the secrets of dark matter in the cosmos. They are searching for dark matter using atomic clocks and cavity-stabilized lasers.

A team of physicists has developed a groundbreaking method for detecting congestive heart failure with greater ease and precision than previously thought possible. This multidisciplinary study, involving both cardiologists and computational physicists, builds on the team's earlier breakthroughs, for example, in predicting the risk of sudden cardiac death.

Researchers have developed an innovative method to improve next-generation wireless networks. Their approach ensures faster, more reliable connections by simplifying how large amounts of signal data are managed and using artificial intelligence to predict and correct errors. The findings promise significant benefits for high-speed travel, satellite communication, and disaster response applications.

Epoxy resins are coatings and adhesives used in a broad range of familiar applications, such as construction, engineering and manufacturing. However, they often present a challenge to recycle or dispose of responsibly. Now a team of researchers has developed a method to efficiently reclaim materials from a range of epoxy products for reuse by using a novel solid catalyst.

A new study focusing on Enceladus, a moon of Saturn, shows that the physics of alien oceans could prevent evidence of deep-sea life from reaching places where we can detect it.

In a new study, scientists show that a mix of policy measures, including both technological solutions and behavioral changes, can significantly reduce greenhouse gas (GHG) emissions from energy use in buildings and transport.

Astronomers have characterized the largest-ever early-Universe radio jet. Historically, such large radio jets have remained elusive in the distant Universe. With these observations, astronomers have valuable new insights into when the first jets formed in the Universe and how they impacted the evolution of galaxies.

The 1953 paper in Nature by Watson and Crick positing a structure for DNA is about one page long, while the Wilkins et al. and Franklin and Gosling papers in the same issue are about two pages each. Altogether, these five pages resulted in three Nobel Prizes (it might have been four had Franklin lived).

Sadly, such concision has fallen by the way now that ideology has invaded the journal. This new paper in Nature (below), a perspective that touts the scientific advantage to neurobiology of combining indigenous knowledge with modern science—the so-called “two eyed seeing” metaphor contrived by two First Nations elders in Canada 21 years ago—is 10.25 pages long, more than twice as long as the entire set of three DNA papers.  And yet it provides nothing even close to the earlier scientific advances.  That’s because, as you might have guessed, indigenous North Americans do not have a science of neurobiology, or ways of looking at the field that might be helpfully combined with what we already know.  What the authors tout at the outset isn’t substantiated in the rest of the paper.

Instead, the real point of the paper is that neuroscientists should treat indigenous peoples properly and ethically when involving them in neurobiological studies. In fact, the paper calls “Western” neuroscientists “settler colonialists,” which immediately tells you where this paper is coming from.  Now of course you must surely behave ethically if you are doing neuroscience, towards both animals and human subjects or participants, but this paper adds nothing to that already widespread view.  And it gives not a single example of how neuroscience itself has been or could be improved by incorporating indigenous perspectives.

The paper is a failure and Nature should be ashamed of wasting over ten pages—pages that could be devoted to good science—to say something that could occupy one paragraph.

Click below to read the paper, which is free with the legal Unpaywall app, or find the pdf here,

My heart is sinking as I realize that I have to discuss this “paper” after reading it twice, but let’s group its contentions under some headings (mine, though Nature‘s text is indented):

What is “two-eyed seeing”? 

This Perspective focuses on the integration of traditional Indigenous views with biomedical approaches to research and care for brain and mental health, and both the breadth of knowledge and intellectual humility that can result when the two are combined. We build upon the foundational framework of Two-Eyed Seeing1 to explore approaches to sharing sacred knowledge and recognize that many dual forms exist to serve a similar beneficial purpose. We offer an approach towards understanding how neuroscience has been influenced by colonization in the past and efforts undertaken to mitigate epistemic, social and environmental injustices in the future.

The principle of Two-Eyed Seeing or Etuaptmumk was conceived by Mi’kmaq Elders, Albert and Murdena Marshall, from Unama’ki (Cape Breton), Nova Scotia, Canada, in 20041 (Fig. 1). It is considered a gift of multiple perspectives, treasured by many Indigenous Peoples, which is enabled by learning to see from one eye with the strengths of Indigenous knowledge and ways of knowing, and from the other eye with the strengths of non-Indigenous knowledge and ways of knowing. It speaks not only to the importance of recognizing Indigenous knowledge as a distinct knowledge system alongside science, but also to the weaving of the Indigenous and Western world views. This integration has attained Canada-wide acceptance and is now widely considered an appropriate approach for researchers working with Indigenous communities.

It is, as you see, a push to incorporate indigenous “ways of knowing” into modern science—in this case neuroscience, though there’s precious little neuroscience in the paper. The paper coiuld have been written using nearly any area of science in which there are human subjects. And, in fact, we do have lots of papers about how biology, chemistry, and even physics can be improved by indigenous knowledge (“two-eyed seeing” is simply the Canadian version of that trope).

And as is so often the case in this kind of paper, there are simple, almost juvenile figures that don’t add anything to the text. The one below is from the paper. Note that modern science is called “Western”, a misnomer that is almost always used, and is meant to imply that the knowledge of the “West” is woefully incomplete.

Isn’t that edifying?

What is two-eyed seeing supposed to accomplish?  Some quotes:

Here we argue that the integration of Indigenous perspectives and knowledge is necessary to further deepen the understanding of the brain and to ensure sustainable development of research4 and clinical practices for brain health5,6 (Table 1 and Fig. 2). We recognize that, in some parts of the world, the term Indigenous is understood differently. We are guided by the United Nations Permanent Forum on Indigenous Issues that identifies Indigenous people as

[…] holders of unique languages, knowledge systems and beliefs and possess invaluable knowledge of practices for the sustainable management of natural resources. They have a special relation to and use of their traditional land. Their ancestral land has a fundamental importance for their collective physical and cultural survival as peoples. Indigenous peoples hold their own diverse concepts of development, based on their traditional values, visions, needs and priorities.

. . . There are many compelling reasons for neuroscientists who study the human brain and mind to engage with other ways of knowing and pursue active allyship, and few convincing reasons to not. Fundamentally, a willingness to engage meaningfully with a range of modes of thought, world views, methods of inquiry and means of communicating knowledge is a matter of intellectual and epistemic humility11. Epistemic humility is defined as “the ability to critically reflect on our ontological commitments, beliefs and belief systems, our biases, and our assumptions, and being willing to change or modify them”12. It shares features with interdisciplinary thinking within Western academic traditions, but it stands to be even more enlightening by providing entirely new approaches to understanding. Epistemic humility is an acknowledgement that all interactions with the world, including the practice of neuroscience, are influenced by mental frameworks, experiences and both unconscious and overt biases.

“Humility” and “allyship” are always red-flag words, and they it is supposed to apply entirely to the settler-colinialist scientists, not to indigenous people.

Why is “one eyed” modern science harmful?  Quotes:

Brain science has largely drawn on ontological and epistemological cultural ways of being and knowing, which are dominantly held in Western countries, such as those in North America and Europe. In cross-cultural neuroscience involving Indigenous people and communities, both epistemic and cultural humility call for an understanding of the history of colonialism, discrimination, injustice and harm caused under a false umbrella of science; critical examination of the origins of current and emerging scientific assessments; and consideration of the way culture shapes engagement between Western and Indigenous research, as well as care systems for brain and mental health.

. . . Why, then, is such engagement with Indigenous ways of knowing not more widespread in human neuroscience research and care? There would seem to be a litany of reasons: ongoing oppression and marginalization of Indigenous peoples in many societies and scientific communities, individual and systemic epistemic arrogance in which only the Western way of knowing is perceived to be of value, lack of knowledge of other knowledge systems, lack of relationships with Indigenous partners that has been fuelled in part by the exclusion and marginalization of Indigenous scholars in academia, challenges to identifying ways of decolonizing or Indigenizing a particular area of study and fear of consequences for making mistakes or causing offence9,15, among others.

. . . Given existing power imbalances, Western knowledge largely dominates the world in which Indigenous peoples reside and, as a result, there is often no choice as to whether to engage with it. In contrast, non-Indigenous peoples have the privilege to choose whether to engage with Indigenous knowledge systems. Although significant learning about Indigenous knowledge systems for settler colonialists remains, full reciprocity is not necessarily a requirement.

Here we see the singling out of power imbalances, the emphasis on colonialism, and the supposed denigration of valuable “indigenous knowledge systems” (which aren’t defined)—all  of which are part of Critical Social Justice ideology. But note the first sentence above: the implication that “two-eyed seeing” is supposed to actually improve brain science itself.

On neuroethics. In fact, the authors give no examples where it does that. Instead, the concentration of the paper is on “neuroethics”.  I talked to my colleague Peggy Mason, a neuroscientist here, about neuroethics, and she told me that it comes in two forms. The first one, which Peggy finds more interesting, is looking at ethical questions through the lens of neuroscience. One example is determinism, and in Robert Sapolsky’s new book Determined you can see how he uses neuroscience to arrive at his deterministic conclusions and their ethical implications.

The other form of neuroethics is the one used in this paper: how to ethically deal with animals and people used in neuroscience studies. These are, in effect, “reserach ethics”, and have been a subject of discussion in recent decades.  As the paper shows above, the real “revolution” in neuroscience touted in the title is simply the realization by those pesky settler-eolonialist neuroscientists that they must exercise sensitivity and empathy towards indigenous people (the implication is that they are uncomprehending and patronizing).

The next section shows the scientific vacuity of melding two types of knowledge: the real “two-eyed seeing” objective.

How has two-eyed seeing improved our understanding of neuroscience? No convincing examples are given in the paper, but here are a few game tries:

Historically, Indigenous peoples have been largely excluded from brain and mental health science, or included but never benefited from the scientific advancements. There are also ample examples, in the brain and mental health sciences and elsewhere, in which the cultural beliefs of Indigenous peoples were patently disrespected. A distinct example is the Havasupai Tribe case, where scientists at Arizona State University in the USA used blood samples they had collected from the Havasupai people to conduct unconsented research on schizophrenia, inbreeding and human population migration20. The Havasupai people, who have strong beliefs about blood and its relation to their sense of identity, spiritual connection and cultural cohesion, were advised that the blood samples were being collected for purposes of conducting diabetes research. The community filed two lawsuits against the university upon learning about the misuse of their blood samples for research questions they do not support.

In another stark example, results from an international genomics study on the genetic structure of ‘Indigenous peoples’ [sic] recruited in Namibia21 were compared to results of a study of the ‘Bantu-speaking people of southern Africa’22,23. The Namibian people were the Indigenous San (including the!Xun, Khwe and ‡Khomani) and Khoekhoe people who include the Nama and Griqua, first to be colonized in southern Africa21. Among numerous missteps in the research, published supplementary materials contained information entirely unrelated to genomics and other information about the San that was unconsented, private, pejorative and discriminatory.

These examples of violations of research ethics in neuroscience and genomics highlight the need for Two-Eyed Seeing to ensure individual and professional scientific integrity.

Neither of these are examples of improvements in understanding neuroscience via “two-eyed seeing”. One is about the proper and ethical way to collect blood from indigenous people; the other is about genetic differences between African populations.

Can we do better? How about an example from studies of mental health?

Other successful studies among the amaXhosa people in South Africa in 2020 exemplify the embodiment of cultural humility and trust-building. Gulsuner et al.29 and Campbell et al.30 demonstrated the importance of inviting people with lived experience of a mental health condition, brain and mental health professionals, members of the criminal justice system, local hospital staff as well as traditional and faith-based healers to provide education about severe mental illness and local psychosocial support structures to promote recovery. Through co-design, implementation and evaluation, the researchers assessed the effects of the co-created mental health community engagement in enhancing understanding of schizophrenia and neuropsychiatric genomics research as it pertains to this disorder30. They collaboratively presented mental health information and research in a culturally sensitive way, both respecting the local conceptualization of mental health and guarding against the possible harms of stigma31. They incorporated cultural practices, such as song, dance and prayer, with the guidance of key community leaders and amaXhosa people that included families affected by schizophrenia, to foster a process of multidirectional enlightenment and, in effect, Two-Eyed Seeing.

Again we see the emphasis on cultural sensitivity, which of course I agree with, but whether and how this method helped us understand how to cure schizophrenia and improve “neuropsychiatric genomics research” is not explained. There may be something there, but the authors fail to tell us what.

Finally, the authors relate the sad story of Lia Lee, a severely epileptic Hmong child in California whose treatment was difficult (she was in a vegetative state for 26 of her 30 years after her last seizure), for the doctors couldn’t communicate with the parents (see here and here) . Treatment was further impeded because the Hmong parents, who really loved Lia deeply, also believed that epilepsy was a sign that she was spiritually gifted, and so were conflicted and erratic in giving her the prescribed medication.  This is an example where some indigenous beliefs are harmful to treatment, just as in some cultures that mistreat people who are mentally ill because they think they are possessed by supernatural powers. Two-eyed seeing is not always good for patients!  From the paper:

Epilepsy serves as a poignant example of how a dual perspective can enrich the spirituality of health and wellbeing, and where collisions with biomedicine can lead to tragic consequences. One example can be taken from the book The Spirit Catches You and You Fall Down, in which author Anne Fadiman51 documents the story of Lia Lee, a Hmong child affected with Lennox–Gastaut syndrome. Lia’s parents attributed the symptoms of her seizures to the flight of her soul in response to a frightening noise—quab dab peg (the spirit catches you and you fall down; translated as epilepsy in Hmong–English dictionaries) and, although concerned, were reluctant to intervene because they viewed its symptoms as a form of spiritual giftedness. Lia’s doctors were faced with limited therapeutic choices, challenges of communication, and a general lack of cultural competence. Exacerbated by disconnects and failures of both traditional and Western healthcare, responsive options and years of effort were eclipsed in a perfect storm of mistrust and misunderstanding.

Since the 1990s when the book was written, closing gaps in health equity, reducing the marginalization of vulnerable and historically neglected populations such as Indigenous peoples and promoting individual and collective autonomy have become a focus in both neuroscience research and clinical care.

Fadiman’s book is read widely in medical schools, used to promote cultural sensitivity towards patients.  That’s fine (though it couldn’t have helped Lia), but again it doesn’t help us understand neuroscience itself.

What are some of the indigenous practices said to contribute to neuroscience?  Several are mentioned, but have nothing to do with neuroscience. Here’s one:

 . . . ,. there remains significant potential integrating Indigenous theories around the brain and mind. For example, while the Kulin nations conceptualize distinct philosophies of yulendj (knowledge/intelligence), toombadool (learning/teaching) and Ngarnga (understanding/comprehension), views of the mind and brain tend to not be static and individualistic, but holistic, dynamic and interwoven symbiotically within the broader environment. The durndurn (brain) is not just a singular organ, but a part of the body that contains some aspects of a murrup (spirit), within the pedagogy of a broader songline.

This concept of a songline is present across many Indigenous cultures35. Although songlines can present as dreaming stories, art, song and dance, their most common use is as a mnemonic. Such is the success of using songlines in memory that it has allowed oral history to accurately survive tens of thousands of years—with accuracy often setting precedent for scientific verification. The breadth of their use would allow the common person to memorize thousands of plants, animals, insects, navigation, astronomy, laws, geological features and genealogy. Whether conceived as songlines, Native American pilgrimage trails, Inca ceques or Polynesian ceremonial roads, all use similar Indigenous methods of memorization36. This aligns with modern neuroscience findings that emphasize the capacity of the brain for complex memory processes and the role of mnemonic techniques in enhancing memory retention. Moser, Moser and O’Keefe were awarded the 2014 Nobel Prize in Physiology or Medicine for research that grounded the relationship between memory and spatial awareness when establishing that entorhinal grid cells form a positioning system as a cognitive representation of the inhabited space. Elevated hippocampal activity when utilizing spatial learning encourages strong memorization through associative attachment, and these techniques are readily used by competitive memory champions. Two-Eyed Seeing songlines for the mind and brain build capacity in facilitating a respectful implementation of traditional memorization techniques in broader contemporary settings37.

Songs and word of mouth allow indigenous people to pass knowledge along. That’s fine, except that knowledge passed on this way may get distorted. Writing—the “settler-colonialist” way of preserving knowledge—is much better and more reliable. It also allows for mathematical and statistical analysis. Again, there is nothing in the two-eyed seeing that improves neuroscience, at least nothing I can see.

There’s a lot more in this long, tedious, and tendentious paper, but I won’t bore you. I do think it would make a great pedagogical tool for neuroscience students, who can evaluate the paper’s claims at the same time as discerning the ideological slant of the paper (as well as its intellectual vacuity).  We’ve come to a pretty pass when one of the world’s two best scientific journals publishes pabulum like this in the interest of sacralizing indigenous people. Yes, indigenous people can contribute knowledge (“justified true belief”) to the canons of science, but, as we’ve seen repeatedly, that knowledge is usually scanty, overblown, and largely irrelevant to modern science. But Social Justice has stuck its nose in the tent science, and papers like this are the result. . .

Genetic analysis suggests a form of mosquito found in urban subway systems evolved in the Middle East thousands of years ago

If you have the patience to repeatedly switch an egg between a hot and a colder pan, you'll be rewarded with an amazing taste and texture, say physicists

A remarkable plesiosaur fossil reveals that the extinct reptiles had scales like modern sea turtles, unlike the ichthyosaurs that lived during the same period

New research suggests an impact recently rattled Mars deeper than thought.

HiRISE images a recent impact crater in the Cerberus Fossae region, seen on March 4, 2021. Credit: NASA/MRO/HiRISE

Something really rang the Red Planet’s bell. Research involving two NASA missions—the Mars Reconnaissance Orbiter, and the late InSight lander—has shed light on meteorite impacts and the seismic signals they produce. In a crucial finding, these signals may penetrate deeper inside Mars than previously thought. This could change how we view the interior of Mars itself.

The interior of Mars, and InSight’s detection of impacts versus geologic activity. Credit: NASA/JPL-Caltech.

The study comes from two papers published this week in the journal of Geophysical Research Letters. The primary data comes from NASA’s InSight mission, the first dedicated geodesy mission to Mars. Insight landed in the Elysium Planitia region of Mars on November 26th, 2018, and carried the first ever dedicated seismometer to the Red Planet. During its four years of operation, Insight detected over 1,300 ‘marsquakes,’ until the mission’s end in 2022. Most were due to geologic activity, while a few were due to distant meteorite impacts. Occasionally, InSight would even see ‘land tides’ due to the passage of the moon Phobos overhead.

InSight uses its robotic arm to place a wind shield over the SEIS seismometer. Credit: NASA/JPL-Caltech. A Distant Mars Impact

As on Earth, the detection of seismic waves gives us the opportunity to probe the interior of Mars, providing clues as to the density, depth and thickness of the crust, mantle and core. To be sure, impacts have been correlated to seismic waves captured by InSight in the past. A fresh crater seen by NASA’s Mars Reconnaissance Orbiter (MRO) in 2022 was correlated to an impact in the Amazonis Planitia region. But this was the first time an impact in the quake-prone Cerberus Fossae area was linked to InSight detections. The find is especially intriguing, as the area is quarter of a world away from the InSight landing site, at 1,640 kilometers (1,019 miles) distant.

A wider context view of the Cerberus Fossae region on Mars, courtesy of Mars Odyssey. NASA/JPL-Caltech.

The discovery of the 21.5-meter (71 foot) crater about the length of a semi-truck immediately presented scientists with a mystery. The smoking gun impact crater was more distant than thought. Typically, the Martian crust was thought to have a dampening effect on distant impacts. This means that the impact-generated waves took a more direct route via a ‘seismic highway,’ through the deeper mantle of the planet itself.

This discovery has key implications for what we generally think about the interior of Mars. This may also imply that our understanding and model for the planet’s interior may be due for an overhaul.

“Composition of the crust and how seismic waves from impacts travel through them is one factor,” Andrew Good (NASA-JPL) told Universe Today. “No current plans for follow-on seismometers on Mars, but there is a seismometer planned for the Moon in the near future,” says Good, in reference to the Farside Seismic Suite planned for 2026.

A New View of the Interior of Mars?

InSight team member Costantinos Charalambous of Imperial College London explains the finding in more detail, in an email to Universe Today:

The detection of this impact changes our understanding of Mars’ interior, particularly its crust and upper mantle, both immediately and in the longer term. However, in the latter case, it will take further work to know quite how!

The immediate shift in our understanding is that many more of the seismic events we detected at InSight have penetrated much deeper into the planet than we thought. Previously, we had thought that the crust would trap most of the high-frequency seismic energy, guiding it around the planet from the point of impact to InSight’s seismometer. We thought any high-frequency energy that penetrated more deeply into the mantle was quickly lost. But it now appears the Martian mantle is much better at propagating this seismic energy than we thought, allowing it to travel more quickly and farther. This tells us that the mantle has a different elemental composition that previously assumed, likely with a lower iron oxide content than earlier models predicted.

Additionally, because this impact was detected in Cerberus Fossae – a region where many recorded marsquakes likely originate – it provides a unique opportunity to distinguish seismic signatures generated by seismic activity driven by deeper, internal (tectonic) forces versus shallower, external (impact) sources.

Therefore, in the longer term, we will be re-examining the data from seismic events that we had previously assumed didn’t penetrate deeper into Mars. This work is ongoing, but these findings suggest new features of Mars’ upper mantle that we are seeking to confirm. Watch this space!

MRO’s Hunt For Impacts

Just how researchers imaged the tiny crater is the amazing second part of the story. NASA’s venerable MRO generates tens of thousands of images of the surface of Mars. These come mainly via the spacecraft’s onboard Context Camera. For years, researchers have used a machine learning algorithm to sift through the images. This looks for fresh impact sites that do not appear in previous frames. These areas are in turn flagged for closer scrutiny with the mission’s 0.5-meter High-Resolution Imaging Science Experiment (HiRISE) camera. The AI program was developed by NASA’s Jet Propulsion Laboratory.

A crater cluster on Mars, one of the first spotted courtesy the MRO AI search program. Credit: NASA/JPL-Caltech/MSSS.

To date, the team has found 123 new craters within 3,000 kilometers (1,864 miles) of the InSight landing site. 49 of these (including the Cerberus Fossae impact) are potential matches with InSight seismology data.

“Done manually, this would be years of work,” says InSight team member Valentin Bickel (University of Bern, Switzerland) in a recent press release. “Using this tool, we went from tens of thousands of images to just a handful in a matter of days.”

InSight’s Legacy

InSight provided a wealth of seismology and geological information about Mars. The Seismic Experiment for Interior Structure (SEIS) instrument worked as planned. The Heat Flow and Physical Properties Package (HP^3) failed, however, to reach its target depth for returning useful science about the planet’s interior. Unfortunately, no dedicated follow on geology mission is set to head to Mars. This sort of exciting science will probably have to wait until the hoped for crewed missions of the 2030s.

InSight was a collaborative effort between NASA, the German Space Agency (DLR) and the French Space Agency (CNES). Other international partners also participated in the ground-breaking mission.

Still, it’s great to see missions like InSight still generating scientific results, long after they’ve fallen silent.

The post A Recent Impact on Mars Shook the Planet to Its Mantle appeared first on Universe Today.

A lidar scanner has a resolution so high it can image ridges and indentations of only 1 millimetre on objects hundreds of metres away – and capture objects as distant as 1 kilometre

When the electron, the first subatomic particle to be identified, was discovered in 1897, it was thought to be a tiny speck with electric charge, moving around on a path governed by the forces of electricity, magnetism and gravity. This was just as one would expect for any small object, given the incredibly successful approach to physics that had been initiated by Galileo and Newton and carried onward into the 19th century.

But this view didn’t last long. Less than 15 years later, physicists learned that an atom has a tiny nucleus with positive electric charge and most of an atom’s mass. This made it clear that something was deeply wrong, because if Newton’s and Maxwell’s laws applied, then all the electrons in an atom should have spiraled into the nucleus in less than a second.

From 1913 to 1925, physicists struggled toward struggled toward a new vision of the electron. They had great breakthroughs and initial successes in the late 1920s. But still, something was off. They did not really find what they were looking for until the end of the 1940s.

Most undergraduates in physics, philosophers who are interested in physics, and general readers mainly learn about quantum physics of the 1920s, that of Heisenberg, Born, Jordan and of Schrödinger. The methods developed at that time, often called “quantum mechanics” for historical reasons, represented the first attempt by physicists to make sense of the atomic, molecular, and subatomic world. Quantum mechanics is all you need to know if you just want to do chemistry, quantum computing, or most atomic physics. It forms the basis of many books about the applications of quantum physics, including those read by most non-experts. The strange puzzles of quantum physics, including the double-slit experiment that I reviewed recently, and many attempts to interpret or alter quantum physics, are often phrased using this 1920s-era approach.

What often seems to be forgotten is that 1920s quantum physics does not agree with data. It’s an approximation, and sometimes a very good one. But it is inconsistent with Einstein’s relativity principle, a cornerstone of the cosmos. This is in contrast to the math and concepts that replaced it, known as relativistic quantum field theory. Importantly, electrons in quantum field theory are very different from the electrons of the 1920s.

And so, when trying to make ultimate conceptual sense of the universe, we should always be careful to test our ideas using quantum field theory, not relying on the physics of the 1920s. Otherwise we risk developing an interpretation which is inconsistent with data, at a huge cost in wasted time. Meanwhile, when we do use the 1920s viewpoint, we should always remember its limitations, and question its implications.

Overview

Before I go into details, here’s an overview.

I have argued strongly in my book and on this blog that calling electrons “particles” is misleading, and one needs to remember this if one wants to understand them. One might instead consider calling them “wavicles“, a term itself from the 1920s that I find appropriate. You may not like this term, and I don’t insist that you adopt it. What’s important is that you understand the conceptual point that the term is intended to convey.

Most crucially, electrons as wavicles is an idea from quantum field theory, not from the 1920s (though a few people, like de Broglie, were on the right track.) In the viewpoint of 1920s quantum physics, electrons are not wavicles. They are particles. Quantum particles.

Before quantum physics, an electron was described as an object with a position and a velocity (or a momentum, which is the electron’s mass times its velocity), moving through the world along a precise path. But in 1920s quantum physics, an electron is described as a particle with a position or a momentum, or some compromise between the two; its path is not definite.

In Schrödinger’s viewpoint [and I emphasize that there are others — his approach is just the most familiar to non-experts], there is a quantum wave function (or more accurately, a quantum state) that tells us the probabilities for the particle’s behavior: where we might find it, and where it might be going.

A wave function must not be identified with the particle itself. No matter how many particles there are, there is only one wave function. Specifically, if there are two electrons, then a single quantum wave function tells us the probabilities for their joint behavior — for the behavior of the system of two electrons. The two electrons are not independent of one another; in quantum physics I can’t say what one’s behavior might be without worrying about what the other is doing. The wave function describes the two electrons, but it is not either one of them.

Then we get to quantum field theory of the late 1940s and beyond. Now we view an electron as a wave — as a ripple in a field, known as the electron field. The whole field, across all of space, has to be described by the wave function, not just the one electron. (In fact, that’s not right either: our wave function has to simultaneously describe all the universe’s fields.) This is very different conceptually from the ’20s; the electron is never an object with a precise position, and instead it is generally spread out.

So it’s really, really important to remember that it is relativistic quantum field theory that universally agrees with experiments, not the quantum physics of the ’20s. If we forget this, we risk drawing wrong conclusions from the latter. Moreover, it becomes impossible to understand what modern particle physicists are talking about, because our description of the physics of “particles” relies on relativistic quantum field theory.

The Electron Over Time

Let me now go into more detail, with hope of giving you some intuition for how things have changed from 1900 to 1925 to 1950.

1900: Electrons Before Quantum Physics A Simple Particle

Pre-quantum physics (such as one learns in a first-year undergraduate course) treats an electron as a particle with a definite position which changes in a definite way over time; it has a definite speed v which represents the rate of the change of its motion. The particle also has definite momentum p equal to its mass m times its speed v. Scientists call this a “classical particle”, because it’s what Isaac Newton himself, the founder of old-school (“classical”) physics would have meant by the word “particle”.

Figure 1: A classical particle (blue dot) moves across across physical space. At the moment shown, it is at position A, and its path takes it to the right with a definite velocity. Two Simple Particles

Two particles are just two of these objects. That’s obvious, right? [Seems as though it ought to be. But as we’ll see, quantum physics says that not only isn’t it obvious, it’s false.]

Figure 2: Two particles, each traveling independently on its own path. Particle 1 moves rapidly to the right and is located at A, while particle 2 moves slowly to the left and is located at B. Two Particles in the “Space of Possibilities”

But now I’m going to do something that may seem unnecessarily complicated — a bit mind-bending for no obvious purpose. I want to describe the motion of these two particles not in the physical space in which they individually move but instead in the space of possibilities for two-particle system, viewed as a whole.

Why? Well, in classical physics, it’s often useful, but it’s also unnecessary. I can tell you where the two particles are in physical space and be done with it. But it quantum physics I cannot. The two particles do not, in general, exist independently. The system must be viewed as a whole. So to understand how quantum physics works, we need to understand the space of possibilities for two classical particles.

This isn’t that hard, even if it’s unfamiliar. Instead of depicting the two particles as two independent dots at two locations A and B along the line shown in Fig. 2, I will instead depict the system by indicating a point in a two-dimensional plane, where

• the horizontal axis depicts where the first particle is located
• the vertical axis depicts where the second particle is located

To make sure that you remember that I am not depicting any one particle but rather the system of two particles, I have drawn what the system is doing at this moment as a star in this two-dimensional space of possibilities. Notice the star is located at A along the horizontal axis and at B along the vertical axis, indicating that one particle is at A and the other is at B.

Figure 3: Within the space of possibilities, the system shown in Fig. 2 is located at the star, where the horizontal axis (the position of particle 1) is at A and the vertical axis (the position of the particle 2) is at B. Over time the star is moving to the right and downward, as shown by the arrow, indicating that in physical space particle 1 moves to the right and the particle 2 to the left, as shown in Fig. 2.

Moreover, in contrast to the two arrows in physical space that I have drawn in Fig. 2, each one indicating the motion of the corresponding particle, I have drawn a single arrow in the space of possibilities, indicating how the system is changing over time. As you can see from Fig. 2,

• the first particle is moving from A to the right in physical space, which corresponds to rightward motion along the horizontal axis of Fig. 3;
• the second particle is moving from B to the left in physical space, which corresponds to downward motion along the vertical axis in Fig. 3;

and so the arrow indicating how the system is changing over time points downward and to the right. It points more to the right than downward, because the motion of the particle at A is faster than the motion of the particle at B.

Why didn’t I bother to make a version of Fig. 3 for the case of just one particle? That’s because for just one particle, physical space and the space of possibilities are the same, so the pictures would be identical.

I suggest you take some time to compare Figs. 2 and 3 until the relationship is clear. It’s an important conceptual step, without which even 1920s quantum physics can’t make sense.

If you’re having trouble with it, try this post, in which I gave another example, a bit more elaborate but with more supporting discussion.

1925: Electrons in 1920s Quantum Physics A Quantum Particle

1920s quantum physics, as one learns in an upper-level undergraduate course, treats an electron as a particle with position x and momentum p that are never simultaneously definite, and both are generally indefinite to a greater or lesser degree. The more definite the position, the less definite the momentum can be, and vice versa; that’s Heisenberg’s uncertainty principle applied to a particle. Since these properties of a particle are indefinite, quantum physics only tells us about their statistical likelihoods. A single electron is described by a wave function (or “state vector”) that gives us the probabilities of it having, at a particular moment in time, a specific location x0 or specific momentum p0. I’ll call this a “quantum particle”.

How can we depict this? For a single particle, it’s easy — so easy that it’s misleading, as we’ll see when we go to two particles. All we have to do is show what the wave function looks like; and the wave function [actually the square of the wave function] tells us about the probability of where we might find the particle. This is indicated in Fig. 4.

Figure 4: A quantum particle corresponding to Fig. 1. The probability of finding the particle at any particular position is given by the square of a wave function, here sketched in red (for wave crests) and blue (for wave troughs). Rather than the particle being at the location A, it may be somewhere (blue dot) near A , but it could be anywhere where the wave function is non-zero. We can’t say exactly where (hence the question mark) without actually measuring, which would change the wave function.

As I mentioned earlier, the case of one particle is special, because the space of possibilities is the same as physical space. That’s potentially misleading. So rather than think too hard about this picture, where there are many potentially misleading elements, let’s go to two particles, where things look much more complicated, but are actually much clearer once you understand them.

Two Quantum Particles

Always remember: it’s not one wave function per particle. It’s one wave function for each isolated system of particles. Two electrons are also described by a single wave function, one that gives us the probability of, say, electron 1 being at location A while electron 2 is simultaneously at location B. That function cannot be expressed in physical space! It can only be expressed in the space of possibilities, because it never tells us the probability of finding the first electron at position 1 independent of what electron 2 is doing.

In other words, there is no analogue of Fig. 2. Quantum physics is too subtle to be squeezed easily into a description in physical space. Instead, all we can look for is a generalization of Fig. 3.

And when we do, we might find something like what is shown in Fig. 5; in contrast to Fig. 4, where the wave function gives us a rough idea of where we may find a single particle, now the wave function gives us a rough idea of what the system of two particles may be doing — and more precisely, it gives us the probability for any one thing that the two particles, collectively, might be doing. Compare this figure to Fig. 2.

Figure 5: The probability of finding the two-particle system at any given point in the space of possibilities is given by the square of a wave function, shown again in red (wave crests) and blue (wave troughs). We don’t know if the positions of the two particles is as indicated by the star (hence the question mark), but the wave function does tell us the probability that this is the case, as well as the probability of all other possibilities.

In Fig. 2, we know what the system is doing; particle 1 is at position A and particle 2 is at position B, and we know how their positions are changing with time. In Fig. 5 we know the wave function and how it is changing with time, but the wave function only gives us probabilities for where the particles might be found — namely that they are near position A and position B, respectively, but exactly can’t be known known until we measure, at which point the wave function will change dramatically, and all information about the particles’ motions will be lost. Nor, even though roughly that they are headed right and left respectively, we can’t know exactly where they are going unless we measure their momenta, again changing the wave function dramatically, and all information about the particles’ positions will be lost.

And again, if this is too hard to follow, try this post, in which I gave another example, a bit more complicated but with more supporting discussion.

1950: Electrons in Modern Quantum Field Theory

1940s-1950s relativistic quantum field theory, as a future particle physicist typically learns in graduate school, treats electrons as wave-like objects — as ripples in the electron field.

[[[NOTA BENE: I wrote “the ElectrON field”, not “the electrIC field”. The electrIC field is something altogether different!!!]

The electron field (like any cosmic field) is found everywhere in physical space.

(Be very careful not to confuse a field, defined in physical space, with a wave function, which is defined on the space of possibilities, a much larger, abstract space. The universe has many fields in its physical space, but only one wave function across the abstract space of all its possibilities.)

In quantum field theory, an electron has a definite mass, but as a ripple, it can be given any shape, and it is always undergoing rapid vibration, even when stationary. It does not have a position x, unlike the particles found in 1920s quantum field theory, though it can (very briefly) be shaped into a rather localized object. It cannot be divided into pieces, even if its shape is very broadly spread out. Nevertheless it is possible to create or destroy electrons one at a time (along with either a positron [the electron’s anti-particle] or an anti-neutrino.) This rather odd object is what I would mean by a “wavicle”; it is a particulate, indivisible, gentle wave.

Meanwhile, there is a wave function for the whole field (really for all the cosmic fields at once), and so that whole notion is vastly more complicated than in 1920s physics. In particular, the space of possibilities, where the wave function is defined, is the space of all possible shapes for the field! This is a gigantic space, because it takes an infinite amount of information to specify a field’s shape. (After all, you have to tell me what the field’s strength is at each point in space, and there are an infinite number of such points.) That means that the space of possibilities now has an infinite number of dimensions! So the wave function is a function of an infinite number of variables, making it completely impossible to draw, generally useless for calculations, and far beyond what any human brain can envision.

It’s almost impossible to figure out how to convey all this in a picture. Below is my best attempt, and it’s not one I’m very proud of. Someday I may think of something better.

Figure 6: In quantum field theory — in contrast to “classical” field theory — we generally do not know the shape of the field (its strength, or “value”, shown on the vertical axis, at each location in physical space, drawn as the horizontal axis.) Instead, the range of possible shapes is described by a wave function, not directly shown. One possible shape for a somewhat localized electron, roughly centered around the position A, is shown (with a question mark to remind you that we do not know the actual shape.) The blue blur is an attempt to vaguely represent a wave function for this single electron that allows for other shapes, but with most of those shapes somewhat resembling the shape shown and thus localized roughly around the position A. [Yeah, this is pretty bad.]

I’ve drawn the single electron in physical space, and indicated one possible shape for the field representing this electron, along with a blur and a question mark to emphasize that we don’t generally know the shape for the field — analogous to the fact that when I drew one electron in Fig. 4, there was a blur and question mark that indicated that we don’t generally know the position of the particle in 1920s quantum physics.

[There actually is a way to draw what a single, isolated particle’s wave function looks like in a space of possibilities, but you have to scramble that space in a clever way, far beyond what I can explain right now. We’ll see it later this year.]

Ugh. Writing about quantum physics, even about non-controversial issues, is really hard. The only thing I can confidently hope to have conveyed here is that there is a very big difference between electrons as they were understood and described in 1920’s quantum physics and electrons as they are described in modern quantum field theory. If we get stuck in the 1920’s, the math and concepts that we apply to puzzles like the double slit experiment and “spooky action at a distance” are never going to be quite right.

As for what’s wrong with Figure 6, there are so many things, some incidental, some fundamental:

• The picture I’ve drawn would be somewhat accurate for a Higgs boson as a ripple in the Higgs field. But an electron is a fermion, not a boson, and trying to draw the ripple without being misleading is kind of impossible.
• The electron field is given by a complex numbers, and in fact more than one, so drawing it as though it has a shape like the one shown in Fig. 6 is an oversimplification.
• At best, Fig. 6 sketches how an electron would look if it didn’t experience any forces. But because electrons are electrically charged and do experience electric and magnetic forces, we can’t just show the electron field without showing the electromagnetic field too; the wave function for an electron deeply involves both. That gets super-complicated.
• The wave function is suggested by a vague blur, but in fact it always has more structure than can be depicted here.
• And there are probably more issues, as I’m sure some readers will point out. Go ahead and do so; it’s better to state all the flaws out loud.

What about two electrons — two ripples in the electron field? This is currently beyond my abilities to sketch. Even ignoring the effects of electric and magnetic forces, describing two electrons in quantum field theory in a picture like Fig. 6 seems truly impossible. For one thing, because electrons are precisely identical in quantum field theory, there are always correlations between the two electrons that cannot be avoided — they can never be independent, in the way that two classical electrons are. (In fact this correlation even affects Fig. 5; I ignored this issue to keep things simpler.) So they really cannot be depicted in physical space. But the space of possibilities is far too enormous for any depiction (unless we do some serious rescrambling — again, something for later in the year, and even then it will only work for bosons.)

And what should you take away from this? Some things about quantum physics can be understood using 1920’s language, but not the nature of electrons and other elementary “particles”. When we try to extract profound lessons from quantum physics without using quantum field theory, we have to be very careful to make sure that those lessons still apply when we try to bring them to the cosmos we really live in — a cosmos for which 1920’s quantum physics proved just as imperfect, though still useful, as the older laws of Newton and Maxwell.

The risk of asteroid 2024 YR4 hitting Earth seems to be creeping up as astronomers gather more data, but does that mean we should be scrambling to prepare for an impact in 2032?

When it comes to vaccines: “If it exists we resist.” 

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