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At least two mass extinction events in Earth's history were likely caused by the 'devastating' effects of nearby supernova explosions, a new study suggests. Researchers say these super-powerful blasts -- caused by the death of a massive star -- may have previously stripped our planet's atmosphere of its ozone, sparked acid rain and exposed life to harmful ultraviolet radiation from the Sun. They believe a supernova explosion close to Earth could be to blame for both the late Devonian and Ordovician extinction events, which occurred 372 and 445 million years ago respectively.

Scientists improved battery durability and energy density with a nano-spring coating.

Researchers have performed the first imaging of embryos using cameras designed for quantum measurements. The academics investigated how to best use ultrasensitive camera technology, including the latest generation of cameras that can count individual packets of light energy at each pixel, for life sciences.

Industrial waste gases, long seen as a major contributor to climate change, could soon be captured and repurposed into everyday household products such as shampoo, detergent, and even fuel.

Some of the world's most advanced AI systems struggle to tell the time and work out dates on calendars, a study suggests.

A modulator has now broken the terahertz mark. The ultrafast component efficiently transmits large volumes of data into the fiber-optic network in a short space of time.

A modulator has now broken the terahertz mark. The ultrafast component efficiently transmits large volumes of data into the fiber-optic network in a short space of time.

With today's data rates of only a few hundred megabytes per second, access to digital information remains relatively slow. Initial experiments have already shown a promising new strategy: Magnetic states can be read out by short current pulses, whereby recently discovered spintronic effects in purpose-built material systems could remove previous speed restrictions. Researchers are now providing proof of the feasibility of such ultrafast data sources. Instead of electrical pulses, they use ultrashort terahertz light pulses, thereby enabling the read-out of magnetic structures within picoseconds.

With today's data rates of only a few hundred megabytes per second, access to digital information remains relatively slow. Initial experiments have already shown a promising new strategy: Magnetic states can be read out by short current pulses, whereby recently discovered spintronic effects in purpose-built material systems could remove previous speed restrictions. Researchers are now providing proof of the feasibility of such ultrafast data sources. Instead of electrical pulses, they use ultrashort terahertz light pulses, thereby enabling the read-out of magnetic structures within picoseconds.

Researchers have discovered a handful of new CRISPR-Cas systems that could add to the capabilities of the already transformational gene editing and DNA manipulation toolbox. Of the new recruits, one system from bacteria commonly found in dairy cows shows particular promise for human health.

Here’s Richard Dawkins ostensibly discussing his new book (The Genetic Book of the Dead) with Steve Pinker, but of course you can’t confine a discussion between these two to a single book. Even from the beginning it ranges widely, in which Pinker discusses not only the epiphany that The Selfish Gene gave him, but levels some trenchant criticisms at Lewontin and Gould’s attacks on adaptationism, and (to my delight) at Gould’s theory of punctuated equilibrium, which never held any water save (perhaps) as the notion that fossil evolution proceeds at varying rates. (People often forget that the novel parts that Gould saw about punc. eq. was its mechanism not its speed: a mechanism that involved questionable propositions like leaping adaptive valleys, macromutations, and species selection (see here for a summary of my beefs with punc. eq., along with scientific references). I myself crossed swords with Gould about these issues, and have concluded that his greatest contribution to science was not any novel paleontological discoveries, but his popularization of evolution in his Natural History essays. (Even those were misleading when they discussed adaptation and punctuated equilibrium.)

Other things discussed: the ubiquity of selection, the nature and importance of epigenetics, the motivation for Richard writing several of his many books, and even “the meaning of life.”  I’ve listened to about 40 minutes of this discussion, but my tolerance for any podcast, even one with these big brains, is limited.  At 1:05:15 begins a Q&A session in which Steve reads audience questions written on cards.

Notice Steve’s cowboy boots, custom made by Lee Miller in Austin.

CubeSats have a lot of advantages. They are small, inexpensive, and easily reproducible. But those advantages also come with significant disadvantages - they have trouble linking into broader constellations that allow them to be more effective at their observational or communication tasks. A team from the University of Albany thinks they might have solved that problem by using a customized calibration algorithm to ensure the right CubeSats link up together.

Bones dating back 25,000 years suggest that humans lived in extremely icy conditions in Tibet, which were previously thought to be uninhabitable

What is really going on in the quantum double-slit experiment? The question raised in this post’s title seems to lie at the heart of the matter. In this experiment, which I recently reviewed here, particles of some sort are aimed, one at a time, at a wall with two slits, and their arrival is recorded on a screen behind the wall. As a parade of particles proceeds, one by one, past the wall, an interference pattern somehow appears, emerging gradually like a spectre on the screen.

Interference is a familiar effect, commonly seen in water waves and sound waves. If water waves passed through a pair of slits in a wall, interference would be observed and no one would be surprised. But here we have one particle passing through the wall at a time; it’s not at all the same thing. How can we explain the interference effect in this case?

It’s natural to imagine that somehow either

• each particle acts like a wave, goes through both slits, and interferes with itself, or
• the quantum wave function that describes each particle (or all the particles [?]) goes through both slits and interferes with itself.

So… which is it? Did the particle go through both slits, or did the wave function?

In 1920s quantum physics, there is a very simple answer to this question.

The answer is,…

“No.“

No — neither the particle nor the wave function [not its wavy pattern or its peak(s) or any other part of it] goes through the two slits.

• What!? Then how can there be interference?

That question I will answer in a later post, probably next week or the following. But first, let’s confront the title of this post in a simpler context, so that we can see clearly why — in 1920s quantum physics — the answer to its question is “neither one”.

The Double Door Experiment

Key to understanding the double-slit experiment is to simplify it down to its bare essence. Having a two-dimensional problem where particles are going through slits in a wall is more complicated than necessary. Instead, let’s take a one-dimensional problem that we’ve already looked at, where an object is in a superposition state of going to the left OR going to the right. We already saw that this object is not to be viewed as both going to the left AND going to the right. By setting up measurements on both sides, we saw that it can only be measured to be doing one or the other, and never both. Superposition is an OR, not an AND. And a true particle can only have one position at a time.

The Particle and the Doors: A First Look

In this context, let’s ask the question: can a particle simultaneously go through two doors on opposite sides of a room? This is the same question as the two-slit question, because I can turn one into the other using tubes behind the slits, as in Fig. 1.

Figure 1: An object can be in a superposition of passing through one slit OR the other; by attaching tubes to the slits we can obtain a superposition of the object going to the right OR to the left. The doors that lie ahead are marked in orange.

By sending a particle toward two slits, we can arrange for its wave function to be in the superposition state we want (Fig. 2)

Figure 2: The wave function of a single particle in a superposition of traveling to the left towards one door or traveling to the right towards the other door.

and then we can ask whether we can observe it going through both doors.

Well, in a recent post we put two balls in the same locations that we now want to place the doors, and we asked if a particle in this very same superposition state can hit both balls simultaneously. The answer was “no”. The same argument applies here; the particle cannot be observed to pass through both doors simultaneously. It can only go through one or the other.

Why? A particle, which has a position and a momentum (even if unknown to us), cannot have two positions. If it starts between the two doors, it can move through one door or the other, but it cannot do both, because then it would have two positions at once.

Maybe you’re not immediately convinced. If not, stay tuned, as I’ll come back to this again later.

The Wave Function and the Doors: A First Look

But for now, let’s turn to the other question arising from my post’s title. Why can’t the particle’s wave function move through both doors, just like a water wave or sound wave does?

Actually, since wave functions don’t move (they just describe particles that do) what we really want to know is slightly different. The initial wave function has a wavy pattern; does this wavy pattern go through both doors?

Certainly water waves and sound waves could go through both doors. They are waves in physical space. So are the doors (or slits) they they can pass through.

But the wave function is a wave in the space of possibilities, and not in physical space. Conversely, the doors do not exist in the space of probabilities; doors are physical objects. Therefore the wave function (and its wavy patterns) cannot pass through the doors at all!

The very idea is nonsensical, the sort of thing that René Magritte would have enjoyed painting. Having the wave function (or its pattern) pass through physical doors would be akin to you entering into Shakespeare’s Romeo and Juliet to save the lovers from their fates, or enjoying the taste of an apple painted by Rembrandt, or walking through a giant hole in a physicist’s argument. Physical space and the space of possibilities are conceptually different; they have distinct meanings. At best one space merely represents what is happening in the other. And so the objects that exist in one don’t exist as objects in the other. (Even when these spaces have the same shape, which sometimes they do, they represent different things, as indicated in the fact that they have different axes.)

To convince you further of these statements, let’s take a look at a simpler example. Consider a system where there is just a single door, but there are two particles. Let’s see why the wave function of these particles (and its wave pattern) can’t even pass through one door, much less two.

The Wave Function of Two Particles and a Single Door

We’ll put the door on the right in physical space. Superposition states aren’t needed here, so instead we’ll send both particles rightward toward the door, in simple wave-packet states. These two particles will be given the same near-definite momentum, but their poorly known positions are shifted apart, so that they are separated in physical space. In pre-quantum language, the set-up is shown in Fig. 3.

Figure 3: The pre-quantum picture of our system: two particles travel at the same speed to the right toward an open door (orange).

What wave function do we need to describe this? It’s simplest to put the two particles in wave packet states with near-definite momentum, somewhat separated in space but with similar motion. You might first think the wave function for such a system would roughly look like Fig. 4:

Figure 4: The wrong wave function! Even though it appears as though this wave function shows two particles, one trailing the other, similar to Fig. 3, it instead shows a single particle with definite speed but a superposition of two different locations (i.e. here OR there.)

But no! That’s a trap that’s super-easy to fall into; such a wave function describes one particle in a superposition of two locations, not two particles.

Instead, because the first particle has position x1 and the second has position x2 respectively, their wave function, a function that exists in the two dimensional space of possibilities with axes x1 and x2, takes the form ψ(x1,x2). If we start with x1 near 2 and x2 near 0, as in Fig. 3, then the wave function for these two particles looks like Fig. 5: it has a peak near x1=2 and x2=0. (The dashed black lines are just there to guide your eyes.) The peak indicates that x1 near 2 and x2 near 0 are the most probable values for the two particles’ positions.

Figure 5: The initial wave function of our system, with particle 1 located near x1=2 and particle 2 located near x2=0. The dashed lines are there to guide the eye. The vertical axis is the absolute value of the wave function, whose square at a certain point gives the probability for the corresponding possibility. The colors represent the wave function’s complex argument [or “phase”].

Now, where’s the door that we want to try to make the wave function go through? Great question. In physical space it is located at x=+4. Let’s now draw that door in the space of possibilities, whose axes are x1 and x2. How should we do that?

Think it over…

Unsure? Confused?

That’s fine; there’s no reason not to be confused the first time you think about it. Here’s the answer.

Particle 1 goes through the door when x1=+4, which is the vertical blue dashed line in Fig. 6. Meanwhile, particle 2 goes through it when x2=+4, so that’s the horizontal blue dashed line.

Figure 6: The door (or rather, the locations where the particles meet the door) in the space of possibilities. Particle 1 is located at the door if the two-particle system lies on the vertical blue line; particle 2 is located at the door if the system is on the horizontal blue line.

Does that look like a door to you? Certainly it doesn’t look like the door in physical space. And that’s because in the space of possibilities, the dashed lines are not a door, with mass and thickiness and a material make-up. Instead the lines represent a certain set of possibilities, namely that one of the particles is at the location of the physical door.

In fact, there’s a special point, the intersection at x1=x2=4 where the lines cross, that represents the possibility that both particles are simultaneously at the location of the door. No such intersection of lines exists in physical space. This is an intersection of two classes of possibilities, and such a thing can only exist in the space of possibilities.

The lines divide the space into four regions, representing four more general classes of possibilities, shown in Fig. 7. In the lower left region, both particles are to the left of the door. At far right, particle 1 is to the right of the door while particle 2 is to the left; the reverse is true in the upper left region. Finally, at upper right is the region where both particles are to the right of the door.

Figure 7: How the dashed lines divide the space of possibilities into four general regions, classified by where the two particles are located relative to the door.

The wave function’s pattern moves in the two dimensions that are spanned by the x1 and x2. axes. Both particles are moving to the right in physical space, at approximately the same speed. Consequently, the wave function, as it evolves, carries the most probable state of the system across three of the regions:

• initially both particles are to the left of the door
• then particle 1 is to the right of the door while particle 2 remains to the left
• and finally both particles are to the right of the door.

In pre-quantum physics the path traversed by the two-particle system would look like Fig. 8:

Figure 8: How the pre-quantum two-particle system of Fig. 3 crosses the space of possibilities. The system’s initial configuration is represented as the star. Over time, the first and then the second particle pass through the door. Compare to Fig. 7.

The wave function evolves as shown in Fig. 9, very similarly to Fig. 8.

Fig. 9: The absolute value of the wave function, with its argument (or phase) indicated by the colors. The blue dashed lines are those of Figs. 6-8, and the path of the peak is similar to that shown in Fig. 8.

Now, is the wave function going through the door? Again, there is no door here; there are simply lines that tell us when one particle is coincident with the door, as well as a point where both particles are coincident with the door. It’s true that the wavy pattern and the peak of the wave function (which indicates the possibilities where the system is most likely to be found are passing across the lines. But can we say the wave function (or its wavy pattern) passes through the lines?

No: moving through a door involves moving in physical space, along the x-axis, through a gap in a door frame. This is something the wave function does not — cannot — do.

The Wave Function of Two Particles and Two Doors

If you’re still not yet entirely convinced, consider what happens if we have two doors, one on each side. Let’s put our two particles each in a superposition state of moving leftward or moving rightward. Again we’ll set one particle off before the other, so that the first will reach the doors well before the second does.

Our pre-quantum view of such as system is that it now has four possibilities: particle 1 can be going right or left, and particle 2 can be going right or left, as shown in Fig. 10. Only the upper-right option appeared in Fig. 3.

Figure 10: Now with two doors and both particles in left/right superpositions, the four pre-quantum possibilities generalizing Fig. 3.

This requires a wave function that initially looks like Fig. 11, with four peaks, one for each general possibility sketched in Fig. 10.

Figure 11: The initial wave function has four peaks, corresponding to the four possibilities in Fig. 10; compare to Fig. 5.

But where are the two doors? They appear in the space of possibilities on four lines; in addition to the blue lines we had in Figs. 6-9, corresponding to particles 1 or 2 being at the righthand door, we now have two more, shown in green in Fig. 12, corresponding to one or the other particle being at the lefthand door.

Figure 12: The generalization of Fig. 6 to the case of two doors. The locations where the particles are at the left door are marked as green dashed lines; the blue dashed lines indicate where the particles are at the right door.

Notice the two intersections between the blue and green lines! What are these?! No such intersections between the doors can possibly occur in physical space. So this makes it even clearer that these lines cannot be identified with the doors.

What do these two intersections actually represent? The upper left intersection combines the possibility that particle 1 is at the left door and simultaneously particle 2 is at the right door. It’s the other way around at the lower right intersection.

Note there is no intersection, or any point at all, corresponding to particle 1 being at the left door and simultaneously being at the right door. Indeed, such a point would have x1=-4 AND x1=+4, which is impossible; every point in the space of possibilities has a unique value of x1.

How does the wave function behave over time? It behaves as shown in Fig. 13:

Figure 13: How the wave function of Fig. 10 evolves over time; each peak takes a path similar to that of Fig. 9.

What are the four peaks, and what are they doing? They correspond to the four possibilities shown in Fig. 10. Clockwise from the rightmost peak (which appeared in Fig. 9,)

1. particle 1 goes through the right door, followed by particle 2.
2. particle 1 goes through the right door, after which particle 2 goes through the left door.
3. particle 1 goes through the left door, followed by particle 2.
4. particle 1 goes through the left door, after which particle 2 goes through the right door.

You can tell which is which by looking at which colored line is crossed first, and which is crossed second, by each peak.

Any one of these four things may happen. Two, or more, may not. And not one of them includes the possibility that either particle goes through both doors simultaneously.

Variation on the Theme

As another instructive variation, suppose we send particles 1 and 2 off at exactly the same moment. Then the wave function, shown in Fig. 13, looks very similar to Fig. 12, except that every peak goes through an intersection of the dashed lines, because the two particles arrive at the doors simultaneously.

Figure 13: As in Fig. 12, but with the two balls no longer shifted relative to one another, so that they arrive simultaneously at one door or the other.

Again there are four possibilities,

1. both particles can arrive at the right door simultaneously,
2. both can arrive at the left door simultaneously,
3. particle 1 can arrive at the left door just as the particle 2 arrives at the right door
4. or vice versa.

And so it certainly is possible for particle 1 to go through the left door and particle 2 to go through the right door simultaneously. No problem with that.

However, it is simply impossible — illogical, in fact — for particle 1 to go through both doors simultaneously. There’s no spot in the space of possibilities that could even represent that inconsistent scenario.

Lessons for the Double Slit Experiment

The lesson? Many fascinating things happen in quantum physics once we have superpositions and multiple particles and multiple doors. But two things that cannot happen (in 1920’s quantum physics) include the following:

• No particle can go through two doors at once; it can have only one position at a time.
• No wave function, living as it does in the space of possibilities, can pass through any door in physical space.

The same applies for the two slits in the quantum double-slit experiment. One cannot make sense of that experiment without learning this lesson: from the viewpoint of 1920’s quantum physics, the interference effects do not arise from any object, whether particle or wave function or pattern in the wave function, physically moving through the physical slits in physical space.

So where do the interference effects come from? The wave function’s pattern can travel across regions of possibility space that are associated with the slits. We need to work out the consequences of this observation, and interpret it properly. Stay tuned to this channel; the answer is near at hand.

As I note in my new review of Francis Collins’s new book, The Road to Wisdom: On Truth, Science, Faith, and Trust, he’s a very good scientist and science administrator, but also a pious evangelical Christian (remember the frozen waterfalls that brought him to Jesus?).  Collins had previously written a book arguing that science and Christianity were not only compatible, but complementary ways of finding the truth, but now he’s produced another. As I say in my review of the new book in Quillette (click on screenshot below, or find my review archived here):

While much of the Road to Wisdom reprises the arguments of the earlier book, this new one takes things a bit further. Collins is deeply concerned about the divisions in American society highlighted by the last presidential election, by people’s inability to have constructive discussions with their opponents, and by our pervasive addiction to social media and its “fake news”; and he believes that accepting a harmony between religion and science will yield the wisdom that can mend America.

As the author of Faith Versus Fact: Why Science and Religion are Incompatible, I wouldn’t be expected to laud Collins’s thesis, and I didn’t.  You can read the review for yourself, but I spend a lot of time criticizing Collins’s claim that science combined with religion is the best way to find the “truths”to repair the deep divisions in America’s polity. Even if those divisions—Collins largely means Republicans vs. Democrats—can be repaired, saying that the way forward is combine the “truths” of science and religion is a deeply misguided claim.

I won’t go into details, but of course religion is simply not a way to discover truth, especially since Collins’s definition of “truth” is basically “facts about the world on which everyone agrees”: in other words, empirical truth. Religion can’t find such truths, as it lacks the methodology.  Note that Collins does not espouse Gould’s “Non-Overlapping Magisteria” claim that science and religion are compatible because they deal with completely different issues, with science alone getting the ambit of empirical truth. Gould’s claim, described in his 1999 book Rocks of Ages, was also misguided, and you can read my old TLS critique of it here.) No, Collins asserts that religion can find empirical truths. Sadly, he gives no examples where religion can beat science–just a bunch of questions that religion can supposedly answer (e.g., “How should I live my life?”).

I’ll give one more quote from my review:

What are the truths that religion can produce but science can’t? Collins’s list is unconvincing. It includes the “fact” of Jesus’s resurrection and the author’s unshakable belief that “Jesus died for me and was then literally raised from the dead.” In support of this claim, Collins cites N.T. Wright’s The Resurrection of the Son of God as compelling evidence for the Resurrection, which Collins claims is “historically well documented.” But when I worked my way through the entirety of Wright’s 817-page behemoth, I found that the “historical documentation” consists solely of what’s in the New Testament, tricked out with some rationalisation and exegesis. Neither Collins nor Wright provide independent, extra-Biblical evidence for the crucifixion and resurrection, much less for the Biblical assertion that upon Jesus’s death the Temple split in twain and many dead saints left their tombs and walked about Jerusalem like zombies. Absent solid evidence for these claims, they are little more than wishful thinking.

Other “truths” that one finds in religion are “moral truths”: the confusing set of rules that Collins labels the “Moral Law.” To him, the fact that our species even has morality constitutes further evidence for God, for Collins sees no way that either evolution or secular rationality could yield a codified ethics. That claim is belied by the long tradition of secular ethics developed by people like Baruch Spinoza, Peter Singer, Immanuel Kant, and John Rawls. While many faiths and societies aspire to common goals like “love, beauty, goodness, freedom, faith, and family,” this does not suggest the existence of a supernatural being.

Click below (or here):

Although it seems obvious to me that religion and science are incompatible insofar as both make empirical claims (granted, some of faith’s claims are hard to test), it’s not obvious to the many Americans who blithely get their vaccinations but then head to Church and recite the “truths” of the Nicene Creed. Sam Harris pointed this out in a piece he wrote opposing Collins’s appointment as NIH director:

It is widely claimed that there can be no conflict, in principle, between science and religion because many scientists are themselves “religious,” and some even believe in the God of Abraham and in the truth of ancient miracles. Even religious extremists value some of the products of science—antibiotics, computers, bombs, etc.—and these seeds of inquisitiveness, we are told, can be patiently nurtured in a way that offers no insult to religious faith.

This prayer of reconciliation goes by many names and now has many advocates. But it is based on a fallacy. The fact that some scientists do not detect any problem with religious faith merely proves that a juxtaposition of good ideas/methods and bad ones is possible. Is there a conflict between marriage and infidelity? The two regularly coincide. The fact that intellectual honesty can be confined to a ghetto—in a single brain, in an institution, in a culture—does not mean that there isn’t a perfect contradiction between reason and faith, or between the worldview of science taken as a whole and those advanced by the world’s “great,” and greatly discrepant, religions.

While I wouldn’t have opposed Collins’s appointment on the basis of his faith, I would have if he had shown any signs that his faith would affect his science. As it turned out, it didn’t: Collins left his religion at the door of the NIH.  But he continues to proselytize for both Christianity as the “true” faith and for a perfect harmony between science and religion.

In a patronizing New Yorker article (is that redundant?) about Collins and his book that I just discovered, I was sad to see another pal soften his views about Collins, science, and faith:

Steven Pinker, the Harvard psychologist who fiercely criticized Collins’s nomination on account of his “primitive, shamanistic, superstitious” religious views, told me in an e-mail that he had changed his mind about Collins, for two reasons. “One is the sheer competence and skill with which he’s directed the Institutes, blending scientific judgment with political acumen,” Pinker wrote. “The other is a newly appreciated imperative, in an age of increasing political polarization, toward making institutions of science trustworthy to a broad swath of the public, of diverse political orientations.” In a way, I thought, Pinker was saying that representation matters: science has an audience, and the right speaker can persuade all of that audience to listen. “A spokesperson for science who is not branded as a left-wing partisan is an asset for the wider acceptance of science across the political spectrum,” Pinker said. But Collins is more than a spokesperson for science. He is also a kind of representative, within the scientific community, of American communities that his peers sometimes fail to reach.

Pinker’s first point is right, and, as I said, I wouldn’t—and didn’t—oppose Collins’s nomination as NIH director.But the author then interprets Pinker as making the “Little People” argument: science will be accepted more broadly if scientists accept religion, even if those scientists don’t practice it. In other words, we have to avoid criticizing superstition if America is to fully embrace science.

But while there’s no need for scientists to bang on about religion when we’re teaching about or promoting science, no scientist should ever approve of a belief in unevidenced superstition, or of any system of such supterstition.  Yet that’s exactly what Collins does in his book, and it’s why the book is misguided, flatly wrong about accommodationism, and unenlightening.

New Scientist has used freedom of information laws to obtain the ChatGPT records of Peter Kyle, the UK's technology secretary, in what is believed to be a world-first use of such legislation

If you think about the human hand as a work of engineering, it is absolutely incredible. The level of fine motor control is extreme. It is responsive and precise. It has robust sensory feedback. It combines both rigid and soft components, so that it is able to grip and lift heavy objects and also cradle and manipulate soft or delicate objects. Trying to replicate this functionality with modern robotics have been challenging, to say the least. But engineers are making steady incremental progress.

I like to check it on how the technology is developing, especially when there appears to be a significant advance. There are two basic applications for robotic hands – for robots and for prosthetics for people who have lost their hand to disease or injury. For the latter we need not only advances in the robotics of the hand itself, but also in the brain-machine interface that controls the hand. Over the years we have seen improvements in this control, using implanted brain electrodes, scalp surface electrodes, and muscle electrodes.

We have also seen the incorporation of sensory feedback, which greatly enhances control. Without this feedback, users have to look at the limb they are trying to control. With sensory feedback, they don’t have to look at it, overall control is enhanced, and the robotic limb feels much more natural. Another recent addition to this technology has been the incorporation of AI, to enhance the learning of the system during training. The software that translates the electrical signals from the user into desired robotic movements is much faster and more accurate than without AI algorithms.

A team at Johns Hopkins is trying to take the robotic hand to the next level – A natural biomimetic prosthetic hand with neuromorphic tactile sensing for precise and compliant grasping. They are specifically trying to mimic a human hand, which is a good approach. Why second-guess millions of years of evolutionary tinkering? They call their system a “hybrid” robotic hand because it incorporates both rigid and soft components. Robotic hands with rigid parts can be strong, but have difficulty handling soft or delicate objects. Hands made of soft parts are good for soft objects, but tend to be weak. The hybrid approach makes sense, and mimics a human hand with internal bones covered in muscles and then soft skin. 

The other advance was to incorporate three independent layers of sensation. This also more closely mimics a human hand, which has both superficial and deep sensory receptors. This is necessary to distinguish what kind of object is being held, and to detect things like the object slipping in the grip. In humans, for example, one of the symptoms of carpal tunnel syndrome, which can impair sensation to the first four fingers of the hands, is that people will drop objects they are holding. With diminished sensory feedback, they don’t maintain the muscle tone necessary to maintain their grip on the object.

Similarly, prosthetics benefit from sensory feedback to control how much pressure to apply to a held object. They have to grip tightly enough to keep it from slipping, but not so tight that they crush or break the object. This means that the robotic limb needs to be able to detect the weight and firmness of the object it is holding. Having different layers of sensation allows for this. The superficial layer detects touch, while the progressively deeper layers will be activated with increasing grip strength. AI is also used to help interpret these signals, which in turn stimulate the users nerves to provide them with natural-feeling sensory feedback.

They report:

“Our innovative design capitalizes on the strengths of both soft and rigid robots, enabling the hybrid robotic hand to compliantly grasp numerous everyday objects of varying surface textures, weight, and compliance while differentiating them with 99.69% average classification accuracy. The hybrid robotic hand with multilayered tactile sensing achieved 98.38% average classification accuracy in a texture discrimination task, surpassing soft robotic and rigid prosthetic fingers. Controlled via electromyography, our transformative prosthetic hand allows individuals with upper-limb loss to grasp compliant objects with precise surface texture detection.”

Moving forward they plan to increase the number of sensory layers and to tweak the hybrid structure of soft and rigid components to more closely mimic a human hand. They also plan to incorporate more industrial-grade materials. The goal is to create a robotic prosthetic hand that can mimic the versatility and dexterity of a human hand, or at least come as close as possible.

Combined with advances in brain-machine interface technology and AI control, robotic prosthetic limb technology is rapidly progressing. It’s pretty exciting to watch.

The post Hybrid Bionic Hand first appeared on NeuroLogica Blog.

A mission to survey the results of a deliberate crash between an asteroid and a NASA spacecraft has taken stunning images of Mars and its moon Deimos

Located on a mountaintop in Chile, the nearly complete Vera C. Rubin Observatory will capture the Universe in incredible detail. This week saw another huge step for the observatory with the installation of the car sized - yes car sized - LSST camera onto the Simonyi Survey Telescope. The camera is the largest ever built, weighing in at over 3,000 kilograms with an impressive 3,200 megapixels. Coupled to the 8.4 metre optics of the Rubin will allow it to capture everything that happens in the southern sky, night after night.

To reduce the growing risk of intense wildfires, California is cutting and burning the areas that fuel them – but these efforts may be moving too slowly