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Most AI diagnostic tools are black boxes, but the approach allows doctors and patients to understand how the computer reached a diagnosis.

Keeping work surfaces clean during meat processing is a challenge, and now researchers deliver key insights into a solution that could change the current practice altogether: Instead of working to prevent bacteria buildup, they created surfaces that stop bacteria from attaching in the first place. Using lasers to etch and alter the surface of the metal, the team was able to create micro- or nanoscale textures that make it difficult for microbial cells to attach to the surface. The technique, known as laser-induced surface texturing, also alters the metal's water-repellent properties.

Air travel produces around 2.5% of all global CO2 emissions, and despite decades of effort in developing alternative fuels or more efficient aircraft designs, that number hasn’t budged much. However, NASA, also the US’s Aeronautics administration, has kept plugging away at trying to build a more sustainable future for air travel. Recently, they supported another step in that direction by providing an Institute for Advanced Concepts (NIAC) grant to Phillip Ansell of the University of Illinois Urbana-Champaign to develop a hybrid hydrogen-based aircraft engine.

The grant focuses on developing the Hydrogen Hybrid Power for Aviation Sustainable Systems (Hy2PASS) engine, a hybrid engine that uses a fuel cell and a gas turbine to power an aircraft. Hybrid systems have been tried before, but Hy2PASS’s secret sauce is its use of air handling.

In hybrid aircraft systems, there’s typically a fuel cell and a gas turbine. The fuel cell takes hydrogen as an input and creates electrical energy as output. In a typical hybrid system, this electrical energy would power a compressor, whose output was directly coupled to turning the turbine. However, in Hy2PASS, the compressor itself is decoupled from the turbine, though it still supplies oxygen to it. It then also supplies oxygen to the fuel cell’s cathode, allowing for its continued operation.

AI generated video on the Hy2PASS system.

This method has a few advantages, but the most significant one is the dramatic increase in efficiency it allows. The waste heat created at that mechanical connection is eliminated by uncoupling the compressor directly from the turbine. Also, it allows the compressor to be run at different pressures, allowing an algorithm to optimize its speed while ignoring the necessary speed of the turbine.

Additionally, the emissions from the entire system are essentially just water. So, this hybrid system effectively eliminates the emissions created by this kind of hybrid engine altogether. So, in theory, at least, this type of propulsion system would be the holy grail that NASA and the rest of the aviation industry have been seeking for years.

There’s still a long way to go to make this system a reality. The Phase I NIAC grant will focus on proving the system’s concept. Importantly, it will also require an understanding of another aircraft system and “mission trajectory optimization” to minimize the energy requirements of any future use case for the system. That sounds like there would be some limitations for how the system might be used in practice, though fleshing that out as part of Phase I seems a reasonable use case.

Interview with Dr. Ansell, the PI on the Hy2PASS project.

If the project is successful, and given Dr. Ansell’s track record of consistently meeting NASA design objectives, that seems a good bet. It is possible that someday soon, a hydrogen-powered aircraft could be in the air again. And this time, it will be a key player in eliminating emissions from one of the most important industries in the world.

Learn More:
NASA – Hydrogen Hybrid Power for Aviation Sustainable Systems (Hy2PASS)
UT – Multimode Propulsion Could Revolutionize How We Launch Things to Space
UT – Reaction Engines Goes Into Bankruptcy, Taking the Hypersonic SABRE Engine With it
UT – NASA is Working on Electric Airplanes

Lead Image:
Artist’s concept of the Hy2PASS engine
Credit – NASA / Phillip Ansell

The post A Hybrid Hydrogen Drive Train Could Eliminate Aircraft Emissions appeared first on Universe Today.

The frozen remains of animals like mammoths, wolves and cave lions offer the most detailed picture yet of the last glacial period

Jon Lovett is identified by Wikipedia as

. . . .  an American podcaster, comedian, journalist, and former speechwriter. Lovett is a co-founder of Crooked Media, along with Jon Favreau and Tommy Vietor. All three formerly worked together as White House staffers during the Obama administration. Lovett is a regular host of the Crooked Media podcasts Pod Save America and Lovett or Leave It. As a speechwriter, he worked for both President Barack Obama and Hillary Clinton when she was a United States senator and a 2008 presidential candidate.

And of course you know who Bill Maher is.  In the ten-minute talk argument below, Lovett and Maher discuss issues of kids with gender dysphoria, including these questions:

a.) Can schools hide a child’s desire to transition sex roles from the parents?

b.) Are there social influences that can promote children to want to change gender roles beyond “feeling like you’re in the wrong body.”

c.) Can the government be allowed to ban “gender-affirming care”?

d) Are children dying (presumably by suicide) because they aren’t allowed to transition?

Lovett actually comes off worse here, mainly because he’s spouting Biden-era dogma about sex and making statements that are scientifically dubious. However, I have to call out Maher near the beginning when he says “Obviously sex is more complicated than just two sexes.”  Yes, sex is complicated, but there are just two sexes. This is the mistake I discussed the other day.

Maher also conflates gender dysphoria with sexual attraction. But in the main, Maher makes some good points, and above all emphasizes that these are questions to be debated, not quashed by “progressives” who slander everyone trying to discuss them as “transphob” or “bigots”.

Maher calls the social conditioning of gender-dysphoric kids “entrapment”, which he defines as “suggesting that people do something that they are not going to do,” or “Putting an idea in someone’s head that wouldn’t be there otherwise.” (In this case, the idea is that the child/adolescent is trapped in the wrong body.)

Lovett, in contrast denies the prevalence of social influence on transitioning, while Maher takes Abigail Shrier’s view that many (but not all) children who decide they are in the wrong body are pushed to transition by peers, doctors, and teachers.  As he says, premature transitioning is medically dangerous and perhaps superfluous, not to mention an issue that can hurt Democrats who support it out of virtue signaling. Maher: “To take that risk at that age, before you know shit about anything. . . ”

Lovett makes the familiar but incorrect argument that without gender-affirming care, many kids would die.  He draws an analogy with cardiology, in which heart surgeons sometimes screw up during surgery and their patients die. But that’s a bogus argument because heart surgeons operate (and patients consent) if the consequences of not having surgery are dire. The difference is that we have enough experience to know the risks and benefits of heart surgery.

But this is not the case for gender dysphoria. Withholding hormones and surgery from kids who are dysphoric does not as often touted, leead to depression and death. (“Do you want a dead son or a live daughter?, some say.)  Yet studies show that about 80% of gender-dysphoric children who are not driven to take hormones and surgery resolve as gay (no medical dangers there!) or even cis.  That is a strong argument against the kind of “gender-affirming care” that puts dysphoric kids on a one-way escalator leading first to puberty blockers and then to hormone treatment and/or surgery.

Maher also seems to know more about the recent science than does Lovett, mentioning the ten-year Olson-Kennedy study showing that puberty blockers, touted by ideologues like Lovett as essential to saving lives, do not in fact improve the well being of gender-dysphoric childrene. From the NYT:

The doctor, Johanna Olson-Kennedy, began the study in 2015 as part of a broader, multimillion-dollar federal project on transgender youth. She and colleagues recruited 95 children from across the country and gave them puberty blockers, which stave off the permanent physical changes — like breasts or a deepening voice — that could exacerbate their gender distress, known as dysphoria.

The researchers followed the children for two years to see if the treatments improved their mental health. An older Dutch study had found that puberty blockers improved well-being, results that inspired clinics around the world to regularly prescribe the medications as part of what is now called gender-affirming care.

But the American trial did not find a similar trend, Dr. Olson-Kennedy said in a wide-ranging interview. Puberty blockers did not lead to mental health improvements, she said, most likely because the children were already doing well when the study began.

“They’re in really good shape when they come in, and they’re in really good shape after two years,” said Dr. Olson-Kennedy, who runs the country’s largest youth gender clinic at the Children’s Hospital of Los Angeles.

Although we the American taxpayers funded this study through the NIH, the results have not yet been released. Why? Because they don’t support the dogma that puberty blockers save lives. Also from the NYT:

In the nine years since the study was funded by the National Institutes of Health, and as medical care for this small group of adolescents became a searing issue in American politics, Dr. Olson-Kennedy’s team has not published the data. Asked why, she said the findings might fuel the kind of political attacks that have led to bans of the youth gender treatments in more than 20 states, one of which will soon be considered by the Supreme Court.

“I do not want our work to be weaponized,” she said. “It has to be exactly on point, clear and concise. And that takes time.”

This is shameful. To suppress important data because they “might fuel political attacks” or go against “progressive” ideology is totally unethical.  Maher knows about that study, as do many of us; but apparently Lovett either does not or deliberately ignores it.

Maher also makes the point that insistence on possibly harmful medical intervention without knowing its long-term effects is a stand that can—and probably has—harmed Democrats. (Yes, some Republicans take this stand because they really don’t want trans people around, but you can take that stand for the right reasons, too.)

Maher’s point, with which I agree completely, is that you don’t go ahead with possibly harmful medical treatment until you know what the harms actually are. 

Without further ado, here is the debate, which is mildly acrimonious:

Grey squirrels can actually come in black morphs, which are doing well in one US city because they're less likely to become roadkill

Varda, a US firm planning to manufacture pharmaceuticals in low Earth orbit, is expecting its second test capsule to return to Earth this week

We have two contributors today, each with a few photos. Once again I’ll ask readers to send in their wildlife photos, as, save for Robert Lang’s Brazil pictures, we’re at an end.  Readers’ captions are indented, and you can enlarge the photos by clicking on them.

Our first trio is from Sharon Diehl in Colorado:

Bald Eagle (Haliaeetus leucocephalus)  Pair atop Transform Tower #199, Wally Toevs Pond, Walden Wildlife Habitat, Boulder, Colorado. I have photographed this mated pair for years at Walden Wildlife Habitat, where they hang out atop the transform towers that overlook Wally Toevs Pond. They aren’t always successful breeders, but they keep at it, together year after year. Red-tailed Hawk (Buteo jamaicensis)  hunting at my backyard bird feeders–where, alas, it caught a bird–at least it was a Starling. I know the raptors have to eat, too: Downy Woodpecker (Dryobates pubescens) on the Hornbeam tree I believe, waiting for the flicker to leave the suet feeder–my backyard, Boulder, Colorado:

. . . and more eagles from Mark Shifman

Obviously I’m not a biologist and these are backyard bird photos. This series is a bald eagle on the Cumberland River.

Researchers study enigmatic asteroid Kamo’oalewa, as China’s first asteroid sample return mission moves toward launch.

China is about to get in to the asteroid sample return game. The CNSA (China National Space Administration) has recently announced that its Tianwen-2 mission has arrived at the Xichang Space Center. The mission will launch this May, on a Long March 3B rocket with the agency’s first solar system exploration mission of the year.

The mission was originally named ZhengHe, after a 15th century explorer. Tianwen-2 is a follow-on to China’s Tianwen-1, the nation’s first successful Mars orbiter-lander mission. Set to launch this coming May, Tianwen-2 will perform an ambitious first: not only will it explore asteroid 469219 Kamo’oalewa, but it will head onward to Comet 311P/PanSTARRS, in a first-ever asteroid-comet exploration mission for the agency.

A Tantalizing Worldlet

Certainly, asteroid Kamo’oalewa is an intriguing space rock. An Apollo Group Near Earth Asteroid, Kamo’oalewa is a rare quasi-satellite of the Earth. Discovered on the night of April 27th, 2016 from the Haleakala Observatory, the asteroid received the provisional designation 2016 HO3. The formal name means ‘oscillating fragment’ in the Hawaiian language. The asteroid currently fluctuates from being a quasi-satellite and horseshoe orbit between the Sun-Earth L1-L2 and L4-L5 Lagrange points, respectively. One day—perhaps a 100 million of years or so in the future—Kamo’oalewa may ultimately strike the Earth or the Moon.

A reddish object, Kamo’oalewa is either an S- or L-type asteroid, about 40 to 100-meters in size. The asteroid also bears a striking spectral resemblance to Apollo 14 and Luna 24 soil returns, suggesting it may in fact be ejecta from the impact that formed the Giordano Bruno crater on the Moon. The farside crater is thought to be about 4 million years old.

Giordano Bruno crater on the lunar farside. Credit: NASA/LRO Following Asteroid Kamo’alewa

A recent study out of the European Space Agency’s Near-Earth Objects Coordination Centre (NEOCC) entitled Astrometry, Orbit Determination and Thermal Inertia of the Tianwen-2 Target Asteroid (469219) Kamo’oalewa is looking to better understand the tiny world ahead of the mission’s arrival. Specifically, the study looks to refine the orbit of the asteroid, and understand how the Yarkovsky and YORP (Yarkovsky-O’Keefe-Radzievskii-Paddack) effects act on the orbit and rotation of the asteroid over time. The Yarovsky Effect is the result of how sunlight alters the path of small asteroids over time, as they absorb solar energy and re-emit it as heat. YORP is a similar phenomena, but includes the scattering of sunlight due to the shape and surface structure of the asteroid. Kamo’oalewa is a fast rotator, spinning on its axis once every 27 minutes. This will add to the challenge of grabbing a sample.

“We observed Kamo’oalewa and precisely measured its position in the sky,” lead researcher on the study Marco Fenucci (ESA/ESRIN/NEO Coordination Centre) told Universe Today. “Thanks to these new measurements, we were able to determine the Yarkovsky effect with a signal-to-noise ratio of 14, and the overall accuracy of the orbit was improved.”

Our best view yet of asteroid Kamo’oalewa. Credit: ESA/NEOCC/Loiano Astronomical Station

The study used current observations from the Calar Alto Observatory in Spain and Loiano Astronomical Station based in Italy, as well as pre-discovery observations found in the Sloan Digital Sky Survey (SDSS) from 2004. These were especially challenging for the team to incorporate, as SDSS used a unique drift scan method to complete images. Also, an NEO asteroid like Kamo’oalewa has a relatively fast proper motion against the starry background. These two factors presented a challenge to pinning the asteroid’s time and location down in earlier images.

An Enigmatic World

“Thanks to the accurate measurement of the Yarkovsky effect on Kamo’oalewa, we were able to estimate the surface thermal inertia,” says Fenucci. “Our best estimate indicates that the thermal inertia is smaller than that of Bennu and Ryugu (the target for JAXA’s Hayabusa2 mission). A low value of thermal inertia is usually due to the presence of regolith on the surface of the asteroid. The presence of regolith was not expected on such fast rotators.”

Certainly, the tiny world is worthy of further scrutiny. Any information will be handy leading up the Tianwen-2’s arrival. Like NASA’s OSIRIS-REx, which sampled asteroid 101955 Bennu in 2020, Tianwen-2 will use a touch-and-go sample technique, in addition to an anchor-and-attach method to acquire its samples of asteroid Kamo’oalewa.

“Kamo’oalewa will be the smallest asteroid visited by a spacecraft, and also the one with the shortest rotation period,” says Fenucci. “In terms of composition, the spectrum is similar to that of S-type asteroids, for example, Itokawa or Eros.” The reddish aspect of the asteroid in the visible-to-near infrared part of the spectrum, however, remains a mystery. “This is a typical feature of lunar regolith,” says Fenucci. “However, this particular feature can also be caused by space weathering. The Tianwen-2 mission should give an answer to the question of the origin of Kamo’oalewa.”

Tianwen-2 Mission Timeline

Currently rendezvous with the asteroid is set for 2026, with a departure in 2027. The CNSA team hopes to nab about 100 grams of Kamo’oalewa, about the mass of medium-sized apple. After that, the mission will dispatch its return capsule on Earth flyby in late 2027. Then, it will head onward to explore periodic comet 311/P PanSTARRS. The mission will reach the comet in 2034.

The Tianwen-2 spacecraft to carry out a sample-return targeting near-Earth asteroid 469219 Kamo?oalewa has arrived at Xichang spaceport. Launch date not revealed, but expected around May. english.news.cn/20250220/d95…

[image or embed]

— Andrew Jones (@andrewjonesspace.bsky.social) February 20, 2025 at 6:08 AM

China has certainly taken a prudent, incremental path to space exploration. CNSA’s Chang’e program has returned samples of the lunar near and far side. Tianwen-1 was successful at Mars, scoring a combination orbiter, lander and rover on the Red Planet, all in one mission. China also has long term plans to combine these proven techniques in a Mars sample return mission of their own. This could launch as early as 2028.

It will be exciting to see asteroid Kamo’oalewa up close, as Tianwen-2 attempts to unravel the origin story for this elusive world.

The post China’s Tianwen-2 Is About to Launch. Here’s What We Know About Its Target Kamo’oalewa appeared first on Universe Today.

In my last post, I looked at how 1920’s quantum physics (“Quantum Mechanics”, or QM) conceives of a particle with definite momentum and completely uncertain position. I also began the process of exploring how Quantum Field Theory (QFT) views the same object. I’m going to assume you’ve read that post, though I’ll quickly review some of its main points.

In that post, I invented a simple type of particle called a Bohron that moves around in a physical space in the shape of a one-dimensional line, the x-axis.

• I discussed the wave function in QM corresponding to a Bohron of definite momentum P1, and depicted that function Ψ(x1) (where x1 is the Bohron’s position) in last post’s Fig. 3.
• In QFT, on the other hand, the Bohron is a ripple in the Bohron field, which is a function B(x) that gives a real number for each point x in physical space. That function has the form shown in last post’s Fig. 4.

We then looked at the broad implications of these differences between QM and QFT. But one thing is glaringly missing: we haven’t yet discussed the wave function in QFT for a Bohron of definite momentum P1. That’s what we’ll do today.

The QFT Wave Function

Wave functions tell us the probabilities for various possibilities — specifically, for all the possible ways in which a physical system can be arranged. (That set of all possibilities is called “the space of possibilities“.)

This is a tricky enough idea even when we just have a system of a few particles; for example, if we have N particles moving on a line, then the space of possibilities is an N-dimensional space. In QFT, wave functions can be extremely complicated, because the space of possibilities for a field is infinite dimensional, even when physical space is just a one-dimensional line. Specifically, for any particular shape s(x) that we choose, the wave function for the field is Ψ[s(x)] — a complex number for every function s(x). Its absolute-value-squared is proportional to the probability that the field B(x) takes on that particular shape s(x).

Since there are an infinite number of classes of possible shapes, Ψ in QFT is a function of an infinite number of variables. Said another way, the space of possibilities has an infinite number of dimensions. Ugh! That’s both impossible to draw and impossible to visualize. What are we to do?

Simplifying the Question

By restricting our attention dramatically, we can make some progress. Instead of trying to find the wave function for all possible shapes, let’s try to understand a simplified wave function that ignores most possible shapes but gives us the probabilities for shapes that look like those in Fig. 5 (a variant of Fig. 4 of the last post). This is the simple wavy shape that corresponds to the fixed momentum P1:

where A, the amplitude for this simple wave, can be anything we like. Here’s what that shape looks like for A=1:

Figure 5: The shape A cos(P1 x) for A=1.

If we do this, the wave function for this set of possible shapes is just a function of A; it tells us the probability that A=1 vs. A=-2 vs. A=3.2 vs. A=-4.57, etc. In other words, we’re going to write a restricted wave function Ψ[A] that doesn’t give us all the information we could possibly want about the field, but does tell us the probability for the Bohron field B(x) to take on the shape A cos(P1 x).

This restriction to Ψ[A] is surprisingly useful. That’s because, in comparing the state containing one Bohron with momentum P1 to a state with no Bohrons anywhere — the “vacuum state”, as it is called — the only thing that changes in the wave function is the part of the wave function that is proportional to Ψ[A].

In other words, if we tried to keep all the other information in the wave function, involving all the other possible shapes, we’d be wasting time, because all of that stuff is going to be the same whether there’s a Bohron with momentum P1 present or not.

To properly understand and appreciate Ψ[A] in the presence of a Bohron with momentum P1, we should first explore Ψ[A] in the vacuum state. Once we know the probabilities for A in the absence of a Bohron, we’ll be able to recognize what has changed in the presence of a Bohron.

The Zero Bohron (“Vacuum”) State

In the last post, we examined what the QM wave function looks like that describes a single Bohron with definite momentum (see Fig. 3 of that post). But what is the QM wave function for the vacuum state, the state that has no Bohrons in it?

The answer: it’s a meaningless question. QM is a theory of objects that have positions in space (or other simple properties.) If there are no objects in the theory, then there’s… well… no QM, no wave function, and nothing to discuss.

[You might complain that the Bohron field itself should be thought of as an “object” — but aside from the fact that this is questionable (is air pressure an object?), the QM of a field is QFT, so taking this route would just prove my point.]

In QFT, by contrast, the “vacuum state” is perfectly meaningful and has a wave function. The full vacuum state wave function Ψ[s(x)] is too complicated for us to talk about today. But again, if we keep our focus on the special shapes that look like cos[P1 x], we can easily write the vacuum state’s wave function for that shape’s amplitude, Ψ[A].

Understanding the Vacuum State’s Wave Function

You might have thought, naively, that if a field contains no “particles”, then the field would just be zero; that is, it would have 100% probability to take the form B(x)=0, and 0% probability to have any other shape. This would mean that Ψ[A] would be non-zero only for A=0, forming a spike as shown in Fig. 6. Here, employing a visualization method I use often, I’m showing the wave function’s real part in red and its imaginary part in blue; its absolute-value squared, in black, is mostly hidden behind the red curve.

Figure 6: A naive guess for the vacuum state of the Bohron field would have B(x) = 0 and therefore A=0. But this state would have enormously high energy and would rapidly spread to large values of A.

We’ve seen a similar-looking wave function before in the context of QM. A particle with a definite position also has a wave function in the form of a spike. But as we saw, it doesn’t stay that way: thanks to Heisenberg’s uncertainty principle, the spike instantly spreads out with a speed that reflects the state’s very high energy.

The same issue would afflict the vacuum state of a QFT if its wave function looked like Fig. 6. Just as there’s an uncertainty principle in QM that relates position and motion (changes in position), there’s an uncertainty principle in QFT that relates A and changes in A (and more generally relates B(x) and changes in B(x).) A state with a definite value of position immediately spreads out with a huge amount of energy, and the same is true for a state with a definite value of A; the shape of Ψ[A] in Fig. 6 will immediately spread out dramatically.

In short, a state that momentarily has B(x) = 0, and in particular A=0, won’t remain in this form. Not only will it change rapidly, it will do so with enormous energy. That does not sound healthy for a supposed vacuum state — the state with no Bohrons in it — which ought to be stable and have low energy.

The field’s actual vacuum state therefore has a spread of values for A — and in fact it is a Gaussian wave packet centered around A=0. In QM we have encountered Gaussian wave packets that give a spread-out position; here, in QFT, we need a packet for a spread-out amplitude, shown in Fig. 7 using the representation in which we show the real part, imaginary part, and absolute-value squared of the wave function. In Fig. 7a I’ve made the A-axis horizontal; I’ve then replotted exactly the same thing in Fig. 7b with the A axis vertical, which turns out to be useful as we’ll see in just a moment.

Figure 7a: The real part (red), imaginary part (blue, and zero) and absolute-value-squared of Ψ[A] (the wave function for the amplitude of the shape in Fig. 5) for the vacuum state. Figure 7b: Same as Fig. 7a, turned sideways for better intuition.

Another way to represent this same wave function involves plotting points at a grid of values for A, with each point drawn in gray-scale that reflects the square of the wave function |Ψ(A)|2, as in Fig. 8. Note that the most probable value for A is zero, but it’s also quite likely to be somewhat away from zero.

Figure 8: The value of |Ψ(A)|2 for the vacuum state, expressed in gray-scale, for a grid of choices of A. Note the most probable value of A is zero.

But now we’re going to go a step further, because what we’re really interested in is not the wave function for A but the wave function for the Bohron field. We want to know how that field B(x) is behaving in the vacuum state. To gain intuition for the vacuum state wave function in terms of the Bohron field (remembering that we’ve restricted ourselves to the shape cos[P1 x] shown in Fig. 5), we’ll generalize Fig. 8: instead of one dot for each value of A, we’ll plot the whole shape A cos[P1 x] for a grid of choices of A, using gray-scale that’s proportional to |Ψ(A)|2. This is shown in Fig. 9; in a sense, it is a combination of Fig. 8 with Fig. 5.

Figure 9: For a grid of values of A, the shape Acos[P1 x] is drawn in gray-scale that reflects the magnitude of |Ψ(A)|2, and thus the probability for that value of A. This picture gives us intuition for the probabilities for the shape of the field B(x) in the vacuum state. The Bohron field is generally not zero in this state, even though the possible shapes of B(x) are centered around B(x) = 0.

Remember, this is not showing the probability for the position of a particle, or even that of a “particle”. It is showing the probability in the vacuum state for the field B(x) to take on a certain shape, albeit restricted to shapes proportional to cos[P1 x]. We can see that the most likely value of A is zero, but there is a substantial spread around zero that causes the field’s value to be uncertain.

In the vacuum state, what’s true for a shape with momentum P1 would be true also for any and all shapes of the form cos[P x] for any possible momentum P. In principle, we could combine all of those shapes, for all of the different momenta, together in a much more complicated version of Fig. 9. However, that would make the picture completely unreadable, so I won’t try to do that — although I’ll do something intermediate, with multiple values of P, in later posts.

Oh, and I mustn’t forget to flash a warning: everything I’ve just told you and will tell you for the rest of this post is limited to a child’s version of QFT. I’m only describing what the vacuum state looks like for a “free” (i.e. non-interacting) Bohron field. This field doesn’t do anything except send individual “particles” around that never change or interact with each other. If you want to know more about truly interesting QFTs, such as the ones in the real world — well, expect some things to be recognizable from today’s post, but much of this will, yet again, have to be revisited.

The One-Bohron State

Now that we know the nature of the wave function for the vacuum state, at least when restricted to shapes proportional to cos[P1 x], how does this change in the presence of a single Bohron of momentum P1?

The answer is quite simple: the wave function Ψ(A) changes from to (up to an overall constant of no interest to us here.) Depicting this state in analogy to what we did for the vacuum state in Figs. 7b, 8 and 9, we find Figs. 10, 11 and 12.

Figure 10: As in Fig. 7, but for the one-Bohron state. Note the probability for A=0 is now zero, and the probability (black curve) peaks at non-zero positive and negative values of A. Figure 10: As in Fig. 8, but for the one-Bohron state. Figure 10: As in Fig. 9, but for the one-Bohron state. Note the probability for B(x)=0 is zero in the one-Bohron state with momentum P1, in contrast to the vacuum state.

Notice that the one-Bohron state is clearly distinguishable from the vacuum state; most notably the probability for A=0 is now zero, and its spread is larger, with the most likely values for A now non-zero.

There’s one more difference between these states, which I won’t attempt to prove to you at the moment. The vacuum state doesn’t show any motion; that’s not surprising, because there are no Bohrons there to do any moving. But the one-Bohron state, with its Bohron of definite momentum, will display signs of a definite speed and direction. You should imagine all the wiggles in Fig. 12 moving steadily to the right as time goes by, whereas Fig. 9 is static.

Well, that’s it. That’s what the QFT wave function for a one-Bohron state of definite momentum P1 looks like — when we ignore the additional complexity that comes from the shapes for other possible momenta P, on the grounds that their behavior is the same in this state as it is in the vacuum state.

A Summary of Today’s Steps

That’s more than enough for today, so let me emphasize some key points here. Compare and contrast:

• In QM:
  • The Bohron with definite momentum is a particle with a position, though that position is unknown.
  • The wave function for the Bohron, spread out across the space of the Bohron’s possible positions x1, has a wavelength with respect to x1.
• In QFT:
  • The Bohron “particle” (i.e. wavicle) is intrinsically spread out across physical space [the horizontal x-axis in Figs. 9 and 12] and the Bohron itself has a wavelength with respect to x.
  • Meanwhile the wave function, spread out across the space of possible amplitudes A (the vertical axis in Figs. 7a, 8, 10 and 11) does not contain simply packaged information about how the activity in the Bohron field is spread out across physical space x; both the vacuum state and one-Bohron states are spread out, but you can’t just read off that fact from Figs. 8 and 11.
  • And note that the wave function has nothing simple to say about the position of the Bohron; after all the spread-out “particle” doesn’t even have a clearly defined position!

Just to make sure this is clear, let me say this again slightly differently. While in QM, the Bohron particle with definite momentum has an unknown position, in QFT, the Bohron “particle” with definite momentum does not even have a position, because it is intrinsically spread out. The QFT wave function says nothing about our uncertainty about the Bohron’s location; that uncertainty is already captured in the fact that the real (not complex!) function B(x) is proportional to a cosine function. Indeed physical space, and its coordinate x, don’t even appear directly in Ψ(A). Instead the QFT wave function, in the restricted form we’ve considered, only tells us the probability that B(x) = A cos[P1 x] for a particular value of A — and that those probabilities are different when there is a single Bohron present (Fig. 12) compared to when there is none (Fig. 9).

I hope you can now start to see why I don’t find the word particle helpful in describing a QFT Bohron. The Bohron does have some limited particle-like qualities, most notably its indivisibility, and we’ll explore those soon. But you might already understand why I prefer wavicle.

We are far from done with QFT; this is just the beginning of our explorations. There are many follow-up questions to address, such as

• Can we put our QFT Bohron into a wave packet state similar to last post’s Fig. 2? What would that look like?
• Do these differences between QM and QFT have implications for how we think about experiments, such as the double-slit experiment or Bell’s particle-pair experiment?
• What do QFT wave functions look like if there are two “particles” rather than just one? There are several cases, all of them interesting.
• How do measurements work, and how are they different, in QM versus QFT?
• What about fields more complicated than the Bohron field, such as the electron field or the electromagnetic field?

We’ll deal with these one by one over the coming days and weeks; stay tuned.

This catchphrase has become popular with comedians. Is that in line with its true origin?

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The chaos and cruelty of its abrupt deconstruction are self-evident and already demonstrable

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In 2007, astronomers discovered the Cosmic Horseshoe, a gravitationally lensed system of galaxies about five-and-a-half billion light-years away. The foreground galaxy’s mass magnifies and distorts the image of a distant background galaxy whose light has travelled for billions of years before reaching us. The foreground and background galaxies are in such perfect alignment that they create an Einstein Ring.

New research into the Cosmic Horseshoe reveals the presence of an Ultra-Massive Black Hole (UMBH) in the foreground galaxy with a staggering 36 billion solar masses.

There’s no strict definition of a UMBH, but the term is often used to describe a supermassive black hole (SMBH) with more than 5 billion solar masses. SMBHs weren’t “discovered” in the traditional sense of the word. Rather, over time, their existence became clear. Also, over time, more and more massive ones were measured. There’s a growing need for a name for the most massive ones, and that’s how the term “Ultra-Massive Black Hole” originated.

The discovery of the enormously massive black hole in the Cosmic Horseshoe is presented in new research. It’s titled “Unveiling a 36 Billion Solar Mass Black Hole at the Centre of the Cosmic
Horseshoe Gravitational Lens,” and the lead author is Carlos Melo-Carneiro from the Instituto de Física, Universidade Federal do Rio Grande do Sul in Brazil. The paper is available at arxiv.org.

There was a revolution in physics in the late 19th/early 20th century as relativity superseded Newtonian physics and propelled our understanding of the Universe to the next level. It became clear that space and time were intertwined rather than separate and that massive objects could warp spacetime. Even light wasn’t immune, and Einstein gave the idea of black holes—which dated back to John Michell’s ‘dark stars’—a coherent mathematical foundation. In 1936, Einstein predicted gravitational lensing, though he didn’t live long enough to enjoy the visual proof we enjoy today.

Now, we know of thousands of gravitational lenses, and they’ve become one of astronomers’ naturally occurring tools. They exist because of their enormous black holes.

The lensing foreground galaxy in the Cosmic Horseshoe is named LRG 3-757. It’s a particular type of rare galaxy called a Luminous Red Galaxy (LRG), which are extremely bright in infrared. LRG 3-757 is also extremely massive, about 100 times more massive than the Milky Way and is one of the most massive galaxies ever observed. Now we know that one of the most massive black holes ever detected occupies the center of this enormous galaxy.

“Supermassive black holes (SMBHs) are found at the centre of every massive galaxy, with their masses tightly connected to their host galaxies through a co-evolution over cosmic time,” the authors write in their paper.

Astronomers don’t find stellar-mass black holes at the heart of massive galaxies and they don’t find SMBHs at the heart of dwarf galaxies. There’s an established link between SMBHs and their host galaxies, especially massive ellipticals like LRG 3-757. This study strengthens that link.

The research focuses on what’s called the MBH-sigmae Relation. It’s the relationship between an SMBH’s mass and the velocity dispersion of the stars in the galactic bulge. Velocity dispersion (sigmae) is a measurement of the speed of the stars and how much they vary around the average speed. The higher the velocity dispersion, the faster and more randomly the stars move.

When astronomers examine galaxies, they find that the more massive the SMBH, the greater the velocity dispersion. The relationship suggests a deep link between the evolution of galaxies and the growth of SMBHs. The correlation between an SMBH’s mass and its galaxy’s velocity dispersion is so tight that astronomers can get a good estimate of the SMBH’s mass by measuring the velocity dispersion.

However, the UMBH in the Cosmic Horseshoe is more massive than the MBH-sigma e Relation suggests.

“It is expected that the most massive galaxies in the Universe, such as brightest cluster galaxies (BCGs), host the most massive SMBHs,” the authors write. Astronomers have found many UMBHs in these galaxies, including LRG 3-757. “Nonetheless, the significance of these UMBHs lies in the fact that
many of them deviate from the standard linear MBH?sigmae relation” the researchers explain.

LRG 3-757 deviates significantly from the correlation. “Our findings place the Cosmic Horseshoe ~1.5 sigma above the MBH?sigmae relation, supporting an emerging trend observed in BGCs and other massive galaxies,” the authors write. “This suggests a steeper MBH?sigmae relationship at the highest masses, potentially driven by a different co-evolution of SMBHs and their host galaxies.”

This figure from the research shows the relationship between the SMBH mass and the host effective
velocity dispersion. The black solid line represents the relation from previous research in 2016, with dashed and dotted lines showing the 1 sigma and 3 sigma scatter, respectively. Horseshoe is labelled and clearly deviates from established relationship. The other galaxies labelled nearby also contain UMBHs that deviate significantly. Image Credit: Melo-Carneiro et al. 2025.

What’s behind this decoupling of the MBH?sigmae relation in massive galaxies? Some stars might have been removed from the galaxy in past mergers, affecting the velocity dispersion.

LRG 3-757 could be part of a fossil group, according to the authors. “The lens of the Horseshoe is unique in that is at ? = 0.44 and that has no comparably massive companion galaxies — it is likely a fossil group,” they write.

Fossil groups are large galaxy groups that feature extremely large galaxies in their centers, often LRGs. Fossil groups and LRGs represent a late stage of evolution in galaxies where activity has slowed. Few stars form in LRGs so they’re “red and dead.” There’s also little to no interaction between galaxies.

“Fossil groups, as remnants of early galaxy mergers, may follow distinct evolutionary pathways compared to local galaxies, potentially explaining the high BH mass,” the authors write.

LRG 3-757 could’ve experienced what’s called “scouring.” Scouring can occur when two extremely massive galaxies merge and affects the velocity dispersion of stars in the galaxy’s center. “In this process, the
binary SMBHs dynamically expel stars from the central regions of the merged galaxy, effectively reducing the stellar velocity dispersion while leaving the SMBH mass largely unchanged,” the authors explain.

Another possibility is black hole/AGN feedback. When black holes are actively feeding they’re called Active Galactic Nuclei. Powerful jets and outflows from AGN can quench star formation and possibly alter the central structure of the galaxy. That could decouple the growth of the SMBH from the velocity dispersion.

Artist view of an active supermassive black hole and its powerful jets. Image Credit: ESO/L. Calçada

“A third scenario posits that such UMBH could be remnants of extremely luminous quasars, which experienced rapid SMBH accretion episodes in the early Universe,” the authors write.

The researchers say that more observations and better models are needed “to explain the scatter in the ?BH ? sigma e relation at its upper end.”

More observations are on the way thanks to the Euclid mission. “The Euclid mission is expected to discover hundreds of thousands of lenses over the next five years,” the authors write in their conclusion. The Extremely Large Telescope (ELT) will also contribute by allowing more detailed dynamical studies of the velocity dispersion.

“This new era of discovery promises to deepen our understanding of galaxy evolution and the interplay between baryonic and DM components,” the authors conclude.

The post One of the Most Massive Black Holes in the Universe Lurks at the Center of the Cosmic Horsehoe appeared first on Universe Today.