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Time loops have long been the stuff of science fiction. Now, using the rules of quantum mechanics, we have a way to effectively transport a particle back in time – here’s how

One of the reasons Claudine Gay didn’t come off so well in the Congressional hearings was that Harvard had no concrete policy on free speech, and thus applied it unevenly, in an almost hypocritical fashion.  Further, it was unclear what the university’s own stand was on issues like genocide.  Were they officially against it, or did calls for genocide of the Jews constitute free speech? In this case Gay answered using Constitutional principles, and her answer, “it depends,” was technically correct.

But the whole mess, including the involvement of MIT and Penn, could have been avoided had these universities adopted two policies that we have at the University of Chicago: the Principles of Free Expression (in effect, First-Amendment-like freedom of speech), and institutional neutrality, as embodied in our Kalven Report. This report mandates that, with very few exceptions, neither the University itself nor its units, including departments and centers, can make official pronouncements on moral, political, or ideological issues. (The exceptions include rare issues that affect the very working of the University itself.)

Indeed, in his Boston Globe article, “A five-point plan to save Harvard from itself,” Steve Pinker’s first two points were free speech and institutional neutrality:

Universities should adopt a clear and conspicuous policy on academic freedom. It might start with the First Amendment, which binds public universities and which has been refined over the decades with carefully justified exceptions.

and

. . . university pronouncements are an invitation to rancor and distraction. Inevitably there will be constituencies who feel a statement is too strong, too weak, too late, or wrongheaded. The resulting apologies and backtracking compromise the reputation of the university and interfere with the task of administering it. For this reason a stated policy of institutional neutrality would be a godsend to university administrators. Such a policy would still allow them to comment on issues that directly affect university business, just like any institution.

I’m not sure what Harvard is doing about its free-speech policy, but I was glad to hear that an eight-person committee has recommended that the school adopt a policy of institutional neutrality. They’ve confected a provisional policy that you can read by clicking on the link below. It hasn’t been formally adopted yet, but some version surely will be.

This policy is an obvious attempt to copy Chicago’s Kalven report, and two of its creators publicized the Harvard policy in a NYT op-ed, an archived version of which you can read by clicking on the archived headline below.

The problem with the Harvard policy lies not in its specifics above, but how it appears to be interpreted by the creators/op-ed writers, who seem to misunderstand the principle of institutional neutrality, try to diss our Kalven Report (perhaps to say, “Hey, Harvard has its own report, and a better one”), and then suggest that Harvard’s policy can in some cases be applied in a non-neutral way. In other words, what we get is a decent policy whose authors (at least two of them) have described for the public as a dog’s breakfast. This does not bode well for any future “institutional neutrality” of Harvard.

Click below to read the archived op-ed, which might have been called of “Harvard’s Very Own Kalven Report.”

Now I’m a big fan of universities adopting institutional neutrality. It would, as Pinker pointed out, save them a lot of trouble and buttress free speech as well. And the official report at the top is pretty good at that. It’s the NYT article, which might reflect how the report is interpreted in action, that seems problematic.

One of the big problems of the NYT piece is its claim that Chicago’s Kalven report wasn’t really institutionally neutral because it embodies the values of a university, and supporting those values is not “institutional neutrality.” I quote from Feldman and Simmons (their words are indented):

This policy might remind some readers of the Kalven Report, a prominent statement of the value of academic “institutional neutrality” issued in 1967 by a University of Chicago committee chaired by the First Amendment scholar Harry Kalven Jr. But while our policy has some important things in common with the Kalven Report, which insisted that the university remain silently neutral on political and social issues, ours rests on different principles and has some different implications.

The principle behind our policy isn’t neutrality. Rather, our policy commits the university to an important set of values that drive the intellectual pursuit of truth: open inquiry, reasoned debate, divergent viewpoints and expertise. An institution committed to these values isn’t neutral, and shouldn’t be. It has to fight for its values, particularly when they are under attack, as they are now. Speaking publicly is one of the tools a university can use in that fight.

This is arrant misinterpretation of the Kalven Report, which of course is not value free; it’s based on assuming the overweening value of free speech and open discussion in a university’s search for truth. Indeed, it’s hard to conceive of a university that isn’t based on those values. Greg Mayer, in an email to me, expressed this faulty comparison very well when writing me about a new interview with Feldman and Simmons in the Harvard Gazette:

[Feldman and Simmons] strain mightily, and unsuccessfully in my opinion, to distinguish what they propose from the Kalven report. Kalven never said the university has no values, just that those values are seldom relevant to current affairs or politics, and thus current affairs or politics will seldom be fit matters for the university to take a stand. There might be disagreement about exactly when the university’s values are implicated, but Kalven does not advocate a value-free university. Far from it, the ability to have open debate without an institutional thumb on the scale, as advocated by Kalven, is one of the most central values of the university.

The second problem is that Feldman and Simmons’s op-ed raises several issues that do seem political, and at best tangentially relevant to the mission of a university, be it Harvard or Chicago. This makes me worry that “Harvard’s Kalven” will be applied erratically.  Here are a couple:

In brief, the report says that university leaders can and should speak out publicly to promote and protect the core function of the university, which is to create an environment suitable for pursuing truth through research, scholarship and teaching. If, for example, Donald Trump presses forward with his announced plan to take “billions and billions of dollars” from large university endowments to create an “American Academy” — a free, online school that would provide an “alternative” to current institutions — Harvard’s leadership can and should express its objections to this terrible idea.

This plan, almost certain not to be enacted, seems just a way to diss Trump. I doubt he can take billions of dollars from University endowments, and only if this plan looks like it actually might happen should the University express an opinion about it.  Here’s another dubious case:

Take the use of affirmative action to achieve diversity in higher education admissions. Harvard argued in defense of this idea in the Supreme Court on several occasions — starting in 1978, when the court’s controlling opinion allowing diversity in admissions relied extensively on a brief that Harvard filed, through 2023, when the court rejected the use of race in diversity-based admissions. Harvard’s advocacy all along was far from neutral and would arguably have violated the Kalven principles. On our principles, however, Harvard was justified in speaking out forcefully in support of the method it long used to admit students, because admissions is a core function of the university.

Again, Harvard trumps Chicago! Well, yes, admissions is a core function of the university, and so is the elimination of bigotry, bias and harassment. But it’s stretching the meaning of Kalven to say that affirmative action is something that should be endorsed because it’s a vital part of the functioning of a university. That is a debatable question, not a given principle essential for a university to function as it should.

Affirmative action, at least when instantiated as race-based hiring or admissions preferences, is a debatable topic, not a moral given. At Chicago, as in all schools, race-based admissions has now been made illegal (at least when used explicitly), and our Shils Report explicitly mandates that hiring and promotion must be based solely on research, teaching, service, and contribution to the intellectual community.  There have been attempts here to use ethnicity as part of the hiring, I’m told, and I’m trying to find out if that happened, and if so whether it violated the Shils report. Official endorsement of affirmative action, or of certain tenets of DEI, regardless of whether they’re enacted sub rosa within the University, would not generally fall under Kalven. On the other hand, the University did endorse the continuing of DACA, for we would have lost students we already admitted were DACA rescinded. Less arguably, that hurts the working of the university. This shows that not all issues are clear cut.

Finally, there’s the contentious issue of divestment, a can that the new report (and NYT article) pretty much kicks down the road.

In formulating its recommendation, our faculty working group struggled with some challenges that don’t have great solutions. For example, we didn’t address, much less solve, the hard problem of when the university should or shouldn’t divest its endowment funds from a given portfolio. The Kalven Report claimed that a decision to divest is a statement in itself and so the university shouldn’t do it. In contrast, we saw divestment as an action rather than a statement the university makes. We therefore treated it as outside our mandate, even though symbolic meaning can be attached to it, just as it can to other actions (including investing in the first place). Our report encourages the university to explain its actions and decisions on investment and divestment — much as Harvard’s President Larry Bacow did in 2021 when the university decided to reduce its investments in fossil fuels, and much as President Derek Bok did when the university didn’t divest from South Africa in the 1980s — but that’s all.

The idea that divestment or investment are actions rather than statements is rather disingenuous; they are certainly regarded as statements by opponents of various investments (to mention a recent one, Israel). The University of Chicago’s policy is not to divulge investments nor to respond to those who call for divestments, a policy that’s held since at least the Vietnam War.

Yet although the Harvard statement doesn’t get into the mire of investment, it does urge the university to take positions on it: “explain its actions and decisions on investment and divestment.”  What is that but a justification of how a University allocates its money? Indeed, disinvestment from fossil fuels is a political “statement”. You might think it’s a good idea, but some people don’t.

In the end, I heartily approve of Harvard’s official proposal, but think that the NYT article is misguided—a recipe for a mushy policy on institutional neutrality. Sure, that kind of neutrality is not always clear-cut, but Feldman and Simmons’s interpretation leaves too many stumps sticking out.

UPDATE: My colleague Brian Leiter also has a note and brief analysis of “Harvard’s Kalven” on his Leiter Reports website, and I agree with his sentiments. His piece is called “Harvard to adopt Chicago’s Kalven Report, after getting burned by pontificating administrators this past fall.” I quote:

That’s the good news.  The bad news is that two Harvard professors (including philosopher Alison Simmons) felt the need to try to pretend what their committee recommended was different from the Kalven Report.   Just reading the latter makes clear how inapt their characterization of it is–it stood for a lot more than “neutrality.”  It was predicated precisely on a statement of the university’s values and missions, and made clear the University and its officers and units should always be free to speak in support of those (including the university’s admissions policies).  Even if Harvard narcissism prevents them from acknowledging it, I am glad they have adopted Kalven principles–the university’s leaders, but also its faculty, will be better for it.

And here’s a tweet that is itself debatable (h/t Eli):

I’m marveling at the fact that Harvard adopted part of institutional neutrality because it couldn’t condemn a terrorist attack on Israel, but not all of it because it still can’t foreclose the possibility of divesting from Israel.

Just incredible. pic.twitter.com/rwWqiybDOE

— Steve McGuire (@sfmcguire79) May 28, 2024

SpaceX is getting ready to launch its massive Starship rocket, perhaps as soon as 5 June, and we have all the details on the mission

Mars is a planet much beloved and much maligned, and in this episode of Dead Planets Society it is getting a dramatic makeover via an enormous orbiting magnet

The latest Jesus and Mo strip, called “brain 2,” is called “a resurrection from 2007.”  According to Wikipedia, “penal substition” is this:

 

Penal substitution, also called penal substitutionary atonement and especially in older writings forensic theory, is a theory of the atonement within Protestant Christian theology, which declares that Christ, voluntarily submitting to God the Father’s plan, was punished (penalized) in the place of (substitution) sinners, thus satisfying the demands of justice and propitiation, so God can justly forgive sins making us at one with God (atonement).

 

And of course that doesn’t make any sense; it’s as opaque as the Trinity. But Mo gives away the game (and the whole of theology) in the last panel.

Google's AI Overviews tool can offer impressive answers to search queries, but it will also make up facts and tell people to eat rocks. Can it be fixed, or will it have to be scrapped?

Today the wildlife is H. sapiens medicalensis: portraits of medical workers taken by reader Christopher Moss in the hospital where he works as a doctor.  To show how intrepid he is, he took one of these when he himself was hospitalized for a bone marrow transplant. (Normally he’s a doctor there.)

Christopher’s captions are indented, and you can enlarge the photos by clicking on them.

These are all portraits taken on film, with a variety of cameras. Many are taken on a weekend morning after rounds at the hospital, when I used to torment the nurses and fellow docs by taking a camera into the hospital. I see there are notices all over the place now declaring photography forbidden except with permission of the micro-managing administrators, so there can be no more such photos.

Emily. Pentax 645N, 75mm/f2.8, Tri-X @400, HC-110, Nikon 9000 scan:

Holly. Nikon F6, 85mm/f1.4, Ilford XP2 @200, Rodinal 1:100 semi-stand:

Treva. Rolleiflex 2.8GX, Rolleinar 1, HP5+ @400, TMax Dev, Imacon 848 scan:

Terry-Lynn. Rolleiflex 2.8GX, HP5+, TMax developer, Imacon 848 scan:

Khaled. Nikon F6, Nikkor 85mm/f1.4, XP2 @ ISO200, Rodinal stand, Imacon 848 scan:

Dan. Nikon F6, Nikkor 85mm/f1.4, XP2 @ ISO200, Rodinal stand, Imacon 848 scan:

Elaine and Chelsie. Nikon F6, Nikkor 85mm/f1.4 AFD, TMax 400 at 400ISO, TMax developer, Imacon 848 scan

Brenda. Leica M7, Summarit 75, TMax400, Rodinal stand, Imacon 848 scan.

Lockdown lunacy. I was not allowed to shave because of a bleeding tendency! Nikon F6, 50/1.4, XP2 @200, HC-110, Nikon 9000 scan: Post-BMT and hairless! Nikon F6, XP2 Super, Diafine, Nikon 9000 scan.

Thomas. Hasselblad 503cx, Sonnar 250mm/f5.5, TMax 100, Diafine, Nikon 9000 scan:

Hasselblad selfie. Hasselblad 500c/m, Distagon 50/4, XP2 Super pushed to 3200, HC-110, Hasselblad X1 scan.

At the core of every atom lies its nucleus, where protons and neutrons are found. As their names suggest, these two subatomic particles are profoundly different.

• Protons carry positive electric charge, and can attract negatively-charged electrons, making atoms possible.
• Neutrons have no electric charge and are thus electrically neutral, hence their name; they have no impact on the electrons in atoms.

The distinctions extend to their magnetic effects. Both protons and neutrons have a “magnetic moment,” meaning that in a magnetic field, they will point like compasses. But neutrons point in the opposite direction from protons, and less agressively.

Nevertheless, the proton and neutron have almost identical masses, differing by less than two tenths of a percent! If we ignored their electric and magnetic effects, they’d almost be twins. Why are they so different in some ways and so similar in others? What does it reflect about nature?

quantityprotonneutronmass
(in units of GeV/c2)0.93830.9396electric charge
(in units of e)10magnetic moment
(in units of e ℏ / 2 mp)2.79-1.86Table 1: The masses (specifically the intrinsic, speed-independent “rest masses”) of the proton and neutron are almost identical, but their electric charge (in units of e) and magnetic responses (in units of e ℏ / 2 mp, where mp is the proton’s mass) are quite different.

To resolve this puzzle required three stages of enlightenment…

Step 1: The Nuclear Force is Strong in These Ones

Atomic nuclei were a puzzle for several decades. The proton was discovered, and identified as the nucleus of hydrogen, before 1920. But other nuclei had larger electric charge and mass; for instance, the helium nucleus has double the charge and about four times the mass of a proton. Only in 1932 was the neutron discovered, after which point it soon became clear that nuclei are made of protons and neutrons combined together. Physicists then realized that to prevent the protons’ mutual electric repulsion from blowing a nucleus apart, there must exist an additional attractive force between the protons and neutrons, now known to be an effect of the “strong nuclear force”, that pulls harder and holds the nucleus together.

Almost immediately following the discovery of the neutron, and noting its similar mass to that of the proton, Heisenberg proposed that perhaps they were the same particle in two different manifestations, despite their different electric charges. Soon it was learned that small atomic nuclei that differ only in the replacing of one proton with one neutron often have remarkably similar masses. For example,

nucleusMagnesium 27Aluminum 27Silicon 27# protons121314# neutrons151413mass (in GeV/c^2)25.135725.133125.1380

Thus, not only are protons and neutrons in isolation almost interchangable (excepting electromagnetism), they remain so when bound together by the strong nuclear force. This is a clue that the strong nuclear force treats them identically, or nearly so. Meanwhile, although their different electromagnetic properties seem of great importance to us at first, they are actually little more than a shiny but irrelevant detail, akin to two different paint colors on cars of exactly the same make.

It turns out the proton and neutron are not quite the same object. But their similarities can still be attributed to similarities in their contents.

Step 2: Bags of Three

Based on the properties of many other particles discovered in the 1940s and 1950s, both Murray Gell-Mann and George Zweig (see also work by A. Petermann) proposed an idea that I’ll refer to as “kuarqs”, in which

• the proton involves two up kuarqs and one down kuarq;
• the neutron involves two down kuarqs and one up kuarq;
• the reason that the proton and neutron are twins is that the up kuarq and down kuarq are twins, differing only in their electric and magnetic effects.

You should note, in addition to my odd spelling, that I did not say “the proton is made of two up kuarqs and one down kuarq”. That’s for a very good reason.

Some physicists, including Zweig, considered that these kuarqs might truly be particles inside a proton. In this view, much as a helium nucleus is a bag made of two protons and two neutrons, each carrying about a quarter of the nucleus’s mass, a proton would be a bag made of three kuarqs, each kuarq carrying a third of the proton’s mass. The neutron would be the same except with one up kuarq replaced with one down kuarq.

A naive picture: protons and neutrons made from three kuarqs each.

These physicists were able to make quite a lot of successful predictions using this viewpoint, in which:

quantityup kuarqdown kuarqmass
(in units of GeV/c2)0.30 – 0.330.30 – 0.33electric charge
(in units of e)2/3– 1/3magnetic moment
(in units of e ℏ / 2 mkuarq)1.9– 0.9Table 3: The simplistic picture of protons and neutrons made from three kuarqs requires they have the above properties; specifically, their masses are roughly 1/3 that of a proton or neutron.

But Gell-Mann (and to some extent Zweig also) emphasized that it would be a mistake to literally view the proton as a simple bag of three objects. The strong nuclear force is too strong for this; such a simplistic view would make the picture inconsistent. Most importantly, other types of related particles, especially pions, would be impossible to explain in a simple way using this method; so how could one expect protons and neutrons to be so simple?

Gell-Mann therefore argued that his kuarqs were mainly a mathematical trick, an organizing device, and were unlikely to actually exist as actual particles. Even if they did exist, he reasoned, they should have very large masses, with the proton mass reduced by the strong nuclear force (due to binding energy, which makes an atom’s mass slightly less than the combined mass of its electrons, protons and neutrons, and similarly reduces the mass of a nucleus below that of its protons and neutrons.)

Step 3: Bags of Plenty

The full story only began to become clear ten years later, in the early 1970s. It turned out that Gell-Mann was right: his kuarqs do not exist. And yet they reflect something that does: a subset of the elementary particles that we call “quarks”.

There are indeed up and down quarks, just as there are up and down kuarqs. But in contrast to kuarqs,

• quarks are real particles, not mere mathematical tools;
• the up and down quarks are not twins;
• protons and neutrons are not made from three quarks.

quantityup quarkdown quarkmass
(in units of GeV/c2)0.0020.005electric charge
(in units of e)2/3– 1/3magnetic moment
(in units of e ℏ / 2 mquark)——Table 4: The elementary up and down quarks. Their masses cannot be precisely determined, but are small and quite different. Their electric charges are the same as for the kuarqs. The magnetic properties of individual quarks are both simple — that of elementary particles — and complex — thanks to the strong nuclear force — but they are certainly very different from those of the kuarqs, thanks to their small masses.

Now perhaps you can understand why I used different spelling for the two things that are pronounced “cworks”. Physicists call Gell-Mann’s kuarqs by the name “constituent quarks”, and elementary quarks by the name “current quarks.” The terms are confusing and very hard to remember; even as a professional, I have to think for a moment to make sure I don’t say one when meaning the other… So I find the different spellings (in a written article) much clearer. [NOTE: I am the only one who does this! Use only with caution.]

As you see, quarks are very different from kuarqs; their masses are very small compared to a proton’s mass, and the down quark mass is more than double that of the up quark. (Actually it took several decades for the table shown above to stabilize, because quarks are never seen individually and their masses must be inferred indirectly.)

The picture of a proton and neutron is then also very different. Instead of imagining three kuarqs moving slowly around a proton, one finds large numbers of fast-moving particles inside. The proton and neutron have almost identical interiors; they contain essentially the same combinations of quarks, anti-quarks and gluons. Their only difference is that a single up quark of the former is exchanged for a single down quark in the latter. More about this viewpoint is explained here or, more carefully, in my book chapter 6.3.

A more realistic, though still quite imperfect, snapshot of a proton and neutron: full of quarks (u,d,s), anti-quarks (with an overbar) and gluons (g), moving around at high speed. Just a single quark distinguishes a proton from a neutron (note the arrow.)

What this means is that the proton and neutron are twins not because the up and down quarks are twins, but rather in spite of the fact that the up and down quarks are not twins. If we convert a proton to a neutron by trading an up quark for a down quark, the neutron’s mass remains the same as the proton’s because the difference between the up and down quark masses is much smaller than that of the proton’s mass, and is thus almost irrelevant.

Essentially, the strong nuclear force brings about the proton and neutron as bags of many fast-moving particles. So strong is that force that any differences in the quarks’ electric effects, magnetic effects, and even their masses are minor details, all of which combine together to explain the very small difference between the proton and neutron masses, as well as their electric and magnetic differences.

With protons and neutrons so complicated, you might well wonder why all protons are the same, all neutrons are the same, and why protons and neutrons are so similar inside. Some discussion of this quantum-physics effect is given in my book’s final chapters.

Kuarqs and Quarks

When quarks of very low mass were discovered in experiments and confirmed in theory, Gell-Mann was quick to insist that he’d known his kuarqs were real particles all along. Clearly this is revisionist history,. Not to take much away from the great man, who deserved his Nobel prize, but he was right the first time. His kuarqs were mathematical objects, and the reason that his kuarq approach (and that of Zweig) worked so well for protons, neutrons and other similar particles is indeed due to the existence of somewhat obscure mathematical symmetries, as pointed out in a wonderful 1994 paper of Dashen, Jenkins and Manohar. This paper does not settle all the issues (specifically it does not address pions and other “mesons”), but it does help make clear the senses in which kuarqs differ from quarks. It also explains why models of protons and neutrons that have no kuarqs in them at all (cf. the “Skyrme model”) can make just as good predictions as those that do, as long as they contain the same obscure mathematical symmetries. Kuarqs, in short, are useful but not necessary concepts.

This is in contrast to quarks, which are elementary particles appearing directly and explicitly in the equations of the Standard Model of particle physics. There are six types, only three of which are reflected in Gell-Mann and Zweig’s kuarqs. They are fundamental ingredients to modern computer simulations that can directly compute the difference between the proton and neutron masses. We can’t do particle physics without them.

Many countries (such as Kenya’s recent regulatory changes regarding Muguka use) are struggling with the dilemma of how to regulate drug use by its citizens. There are many psychoactive drugs (we seem to be good at discovering them) with a variety of effects. Often there may be subjectively desirable effects in the short term, but long term addiction, the potential for withdrawal, […]

The post Khat and Muguka Use in East Africa first appeared on Science-Based Medicine.

Researchers unveil the interaction between polymeric materials and sulfide solid electrolytes.

Cut marks on a 4000-year-old skull suggest ancient Egyptian doctors tried to treat a man with nasopharyngeal cancer

It’s coming back! Sunspot AR3664 gave us an amazing display of northern lights in mid-May and it’s now rotating back into view. That means another great display if this sunspot continues to flare out. It’s all part of solar maximum—the peak of an 11-year cycle of solar active and quiet times. This cycle is the result of something inside the Sun—the solar dynamo. A team of scientists suggests that this big generator lies not far beneath the solar surface. It creates a magnetic field and spurs flares and sunspots.

For a long time, solar physicists thought the magnetic dynamo was deep inside the Sun. That view may change thanks to work by researchers at MIT, the University of Edinburgh, the University of Colorado, Bates College, Northwestern University, and the University of California. The dynamo may be related to instabilities in what’s called the “near-surface shear layer” in the Sun’s outermost regions. The activities in this layer result in the flares and sunspots we see more of as the Sun nears “solar maximum”. Flares are high-energy outbursts while sunspots are surface features with local magnetic fields. Sunspots are relatively cool regions on the solar surface and occur in 11-year cycles.

NASA’s Solar Dynamics Observatory captured these images of the solar flares — as seen in the bright flashes in the upper right — on May 5 and May 6, 2024. The image shows a subset of extreme ultraviolet light that highlights the extremely hot material in flares and which is colorized in teal. The loops are magnetic field lines channeling plasma. Credit: NASA/SDO

“The features we see when looking at the Sun, like the corona that many people saw during the recent solar eclipse, sunspots, and solar flares, are all associated with the sun’s magnetic field,” said MIT researcher Keaton Burns. “We show that isolated perturbations near the sun’s surface, far from the deeper layers, can grow over time to potentially produce the magnetic structures we see.”

How is the Sun’s Magnetic Field Connected to Activity?

To understand the magnitude of this finding, let’s look at the structure of the Sun. We all know the Sun is a superheated ball of plasma. So, how does boiling plasma create a magnetic dynamo? “One of the basic ideas for how to start a dynamo is that you need a region where there’s a lot of plasma moving past other plasma and that shearing motion converts kinetic energy into magnetic energy,” Burns explained. “People had thought that the Sun’s magnetic field is created by the motions at the very bottom of the convection zone.”

The interior structure of our Sun. The dynamo generating a magnetic field could lie very close to the solar surface. Credit: Kelvin Ma, via Wikipedia

Of course, pinning down the exact location of the solar dynamo in the upper layers is difficult. Simulations can only go so far, and modeling the plasma flow throughout the entire Sun is a massive computing task. So, Burns and the team decided simulate a smaller piece of the Sun. They studied the stability of plasma flow near the solar surface. That required helioseismology data showing vibrations on the Sun’s surface, which allowed them to determine the average flow of plasma in that region. “If you take a video of a drum and watch how it vibrates in slow motion, you can work out the drumhead’s shape and stiffness from the vibrational modes,” said Burns. “Similarly, we can use vibrations that we see on the solar surface to infer the average structure on the inside.”

Think of the Sun as layered like an onion. Different plasma layers rush past each other as the Sun rotates, according to Burns. “Then we ask: Are there perturbations, or tiny changes in the flow of plasma, that we could superimpose on top of this average structure, that might grow to cause the sun’s magnetic field?”

Computing an Answer

The team developed algorithms that they incorporated into a numerical framework called the Dedalus Project. They looked for self-reinforcing changes in the Sun’s average surface flows. The algorithm discovered new patterns that could grow and result in realistic solar activity. Interestingly, those patterns also match the locations and timescales of sunspots. It turns out that certain changes in the flow of plasma at the very top of the Sun’s surface layers generate magnetic structures. This isn’t a new idea. Burns pointed out that the conditions there resembled the unstable plasma flows in accretion disks around black holes. Accretion disks are massive collections of gas and stellar dust that rotate in towards a black hole. They’re driven by “magnetorotational instability,” which generates turbulence in the flow and causes it to fall inward.

Burns and the team thought this phenomenon at a black hole might also be at work inside our Sun. They suggest that magnetorotational instability in the Sun’s outermost layers could be the first step in generating its magnetic field. “I think this result may be controversial,” he said. “Most of the community has been focused on finding dynamo action deep in the Sun. Now we’re showing there’s a different mechanism that seems to be a better match to observations.”

Implications of the New Model

Not only will the team’s work help solar physicists understand the creation of the magnetic dynamo, but may give them insight into other solar phenomena. In particular, a dynamo in the upper 10 percent of the Sun may explain things like the Maunder Minimum. This was a period between 1645 to 1715 when there were very few sunspots. In some years, observers saw no sunspots at all. In other years, they observed fewer than 20. Astronomers did chart the 11-year sunspot cycle through that time, so the Sun wasn’t entirely inactive.

If the Sun’s magnetic dynamo operates in its outermost layers, the science of solar activity forecasting could get a big boost. Right now, it’s difficult to tell when a flare might break out. Flares and coronal mass ejections like those that contributed to the May 10-11 geomagnetic storm can damage satellites and telecommunications systems here on Earth. In addition, power grids and other technology are at risk. In the long run, however, gaining new understanding of the Sun’s dynamo is a big deal.

“We know the dynamo acts like a giant clock with many complex interacting parts,” says co-author Geoffrey Vasil, a researcher at the University of Edinburgh. “But we don’t know many of the pieces or how they fit together. This new idea of how the solar dynamo starts is essential to understanding and predicting it.”

For More Information

The Origin of the Sun’s Magnetic Field Could Lie Close to Its Surface
The Solar Dynamo Begins Near the Surface

The post The Sun’s Magnetic Field Might Only Be Skin Deep appeared first on Universe Today.

Start talking about Venus and immediately my mind goes to those images from the Venera space probes that visited Venus in the 1970’s. They revealed a world that had been scarred by millennia of volcanic activity yet as far as we could tell those volcanoes were dormant. That is, until just now.  Magellan has been mapping the surface of Venus and between 1990 and 1992 had mapped 98% of the surface. Researchers compared two scans of the same area and discovered that there were fresh outflows of molten rock filling a vent crater! There was active volcanism on Venus. 

Venus is the second planet from the Sun and similar in size to Earth, the similarities end there though. It has a thick atmosphere that is toxic to life as we know it, there is sulphuric acid rain high in the atmosphere and a surface temperature of almost 500 degrees. When the Venera probes visited they measured an atmospheric pressure of around 90 times that at the Earth’s surface. Combined with the other hostile properties of the atmosphere, a human visitor would not survive long. 

Venus

The dense atmosphere of Venus is largely the result of volcanic activity. Over the millennia, there have been extensive volcanic eruptions that pumped carbon dioxide into the atmosphere. The lack of bodies of water on Venus meant the built up carbon dioxide in the atmosphere didn’t get absorbed. In addition to this, the lack of a magnetic field meant the solar wind – the pressure from the Sun – drove away the lighter elements leaving behind the thick, carbon dioxide rich atmosphere we see today. But the volcanoes that drove the atmospheric changes are thought to have been extinct for a long time. 

It’s not just the Venera probes that have been exploring Venus. In 1980, the Magellan spacecraft was launched by NASA to map the surface of the hottest planet in the Solar System. On arrival, it was put into a polar orbit and used radar to penetrate the thick clouds. Back in 2023, a study of some of the Magellan images from the synthetic aperture radar showed changes to a vent near the summit of Maat Mons. It was the first direct evidence of an eruption on the surface of Venus and changes in the lava flows. 

The surface of Venus captured by a Soviet Venera probe. Credit: Russian Academy of Sciences / Ted Stryk

In the latest study that was published in Nature Astronomy, more data from the synthetic aperture radar was studied. The team focussed on Sif Mons and Niobe Planitia and the data that had been collected from both areas in 1990 and again in 1992. The data revealed stronger radar returns in the later set of data suggesting new rock formations from volcanic activity. The team did consider it may have been caused by some other phenomena such as sand dunes or atmospheric effects but altimeter data confirmed the presence of new solidified lava. 

The team were able to use lava flows on Earth as a comparison to help understand the new flows on Venus. They estimated that the new flows are between 3 and 20 metres deep. They could go a step further though and estimated that the eruption at Sif Mons produced about 30 square kilometres of rock which would be enough to fill over 36,000 swimming pools.  The eruption at Niobe Planitia produced even more with an estimated 45 square kilometres of rock..

Studying volcanic activity on Venus helps to understand not just the geological processes but also helps to understand the structure of the interior too. This can help inform the likelihood of habitability for future explorers. None of which would have been possible without the recent volcanic activity to help us probe further the secrets of Venus.

Source: Ongoing Venus Volcanic Activity Discovered With NASA’s Magellan Data

The post Volcanoes Were Erupting on Venus in the 1990s appeared first on Universe Today.

Researchers have developed a sustainable and controllable strategy to manipulate interfacial heat transfer, paving the way for improving the performance of eco-friendly cooling in various applications such as electronics, buildings and solar panels.

We’re fortunate to live in these times. Multiple space telescopes feed us a rich stream of astounding images that never seems to end. Each one is a portrait of some part of nature’s glory, enriched by the science behind it all. All we have to do is revel in the wonder.

The ESA’s Euclid space telescope is the latest one to enrich our inboxes. It was launched on July 1st, 2023, and delivered its first images in November of that year. Now, we have five new images from Euclid, as well as the first science results from the wide-angle space telescope.

“They give just a hint of what Euclid can do.”

Valeria Pettorino, ESA’s Euclid Project Scientist.

The images demonstrate the telescope’s power and its ability to address some of the deepest questions we have about the Universe. They are also impressive because of their visual richness and because they took only 24 hours of the telescope’s expected six years of observing time.

“Euclid is a unique, ground-breaking mission, and these are the first datasets to be made public – it’s an important milestone,” says Valeria Pettorino, ESA’s Euclid Project Scientist. “The images and associated science findings are impressively diverse in terms of the objects and distances observed. They include a variety of science applications, and yet represent a mere 24 hours of observations. They give just a hint of what Euclid can do. We are looking forward to six more years of data to come!”

The leading image is the most stunning and perhaps the most relatable. It shows Messier 78, aka NGC 2068. It’s a reflection nebula and star-forming region contained in the vast Orion B molecular cloud complex. Euclid used its infrared capabilities to see through the dust that shrouds the star-formation region. It’s given us our most detailed look at the filaments of gas and dust that give the region its ghostly appearance.

Euclid can detect objects that are just a few times more massive than Jupiter, an impressive feat. In its M78 image, it found over 300,000 objects in that mass range.

This zoomed-in portion of Euclid’s M78 image shows the depth the telescope’s images deliver. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi. LICENCE CC BY-SA 3.0 IGO

One of Euclid’s objectives is to study dark matter and how it’s distributed in the Universe. It uses gravitational lensing to probe dark matter, and its image of the Abell 2390 galaxy cluster exhibits the tell-tale curved arcs of light coming from distant background objects created by gravitational lensing. The image also shows more than 50,000 galaxies.

Euclid’s image of the Abell 2390 cluster of galaxies contains over 50,000 galaxies. It also shows the intracluster light that comes from individual stars torn from their galaxies and sitting in intergalactic space. These stars can help astrophysicists determine where dark matter is. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi.
LICENCE: CC BY-SA 3.0 IGO

Most of the stars currently forming in the Universe are forming in spiral galaxies. Euclid captured this image of NGC 6744 as an archetype of that galaxy type. The telescope’s wide-angle lens and depth of field capture the entire galaxy and also small details. It shows lanes of dust that emerge as spurs on the spiral arms.

With this image, astronomers can map individual stars and the gas that feeds their formation. They can also identify globular clusters and new dwarf galaxies. Euclid already found one new dwarf galaxy astronomers have never seen before, which is impressive for a galaxy that’s already been studied so intently.

Euclid’s complete image of NGC 6744 is on the left, and a zoomed-in portion is on the right. NGC 6744 is one of the largest spiral galaxies outside our region of space. The telescope’s detailed image will let astronomers count and map individual stars and the gas that feeds star formation. Star formation is how galaxies evolve, so studying NGC 6744’s star formation activity feeds into a greater understanding of galaxy evolution. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi. LICENCE: CC BY-SA 3.0 IGO

Euclid also imaged another galaxy cluster, Abell 2764. This cluster contains hundreds of galaxies within a halo of dark matter. Euclid’s impressive wide-field view comes into play in this image. Not only does it show Abell 2764 in the image’s upper right, but it also shows other clusters that are even more distant, multiple background galaxies, and interacting galaxies with their streams of stars.

In this image, Euclid captured galaxy cluster Abell 2764 and the wider region surrounding it. Abell 2764 is in the upper right corner. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi LICENCE CC BY-SA 3.0 IGO

The image highlights one of Euclid’s other capabilities. The foreground star is in our own galaxy, and when viewed with a telescope, its diffuse light creates a halo that obscures distant objects behind it. Euclid was built to minimize that diffuse halo effect. The disturbance from the star’s diffuse light is minimal, meaning Euclid can see distant background objects near the star’s line of sight.

This pair of zoomed-in images of Abell 2764 shows Euclid’s power. On the left is the foreground star. These stars can create halos of diffuse light that obscure other objects, but Euclid is built to minimize the effect. On the right is a zoom-in of Abell 2764 itself, with multitudes of background galaxies. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi. LICENCE: CC BY-SA 3.0 IGO

The final of the five new images is of galaxies in the Dorado Group. Euclid’s image shows signs of galaxies merging. The Dorado Group is a relatively young group, and many of its member galaxies are still forming stars. The image helps astronomers study how galaxies form and evolve inside halos of dark matter.

The Dorado Group is one of the richest galaxy groups in the southern hemisphere. Euclid’s wide and deep images give astronomers their best look at it. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi. LICENCE: ESA Standard Licence

A zoomed-in image shows more detail of the main pair of galaxies in the image. Euclid’s unique large field-of-view and high spatial resolution means that for the first time, astronomers can use the same instrument and observations to deeply study tiny objects the size of star clusters, intermediate objects like the central regions of galaxies, and larger features like tidal tails in one large region of the sky.

“The beauty of Euclid is that it covers large regions of the sky in great detail and depth, and can capture a wide range of different objects all in the same image – from faint to bright, from distant to nearby, from the most massive of galaxy clusters to small planets.”

ESA Director of Science, Prof. Carole Mundell

Prior to Euclid, astronomers had to use small chunks of data to painstakingly catalogue globular clusters around galaxies. But Euclid’s wide images capture far more data in a single image, simplifying the task. Globular clusters provide important clues to how galaxies evolve over time.

This zoom-in shows a pair of interacting galaxies in the Dorado Group. Tidal tails of stars are visible as wispy streams near the right and bottom right of the right-side galaxy. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi. LICENCE: ESA Standard Licence

Euclid’s mission is only starting. The telescope’s images so far have no equivalent, and there’s much more to come. Euclid hasn’t even begun its main survey yet. That survey will comprise both a wide survey covering about 15,000 square degrees of the sky and a deep survey covering about 50 square degrees.

“It’s no exaggeration to say that the results we’re seeing from Euclid are unprecedented,” says ESA Director of Science, Prof. Carole Mundell. “Euclid’s first images, published in November, clearly illustrated the telescope’s vast potential to explore the dark Universe, and this second batch is no different.”

“The beauty of Euclid is that it covers large regions of the sky in great detail and depth, and can capture a wide range of different objects all in the same image – from faint to bright, from distant to nearby, from the most massive of galaxy clusters to small planets,” said Mundell. “We get both a very detailed and very wide view all at once. This amazing versatility has resulted in numerous new science results that, when combined with the results from Euclid’s surveying over the coming years, will significantly alter our understanding of the Universe.”

The scientific papers released with these images are available here.

The post Enjoy Five New Images from the Euclid Mission appeared first on Universe Today.

Offshore wind could have prevented the Fukushima disaster, according to a review of wind energy.

Several psychological biases undermine our ability to make new friends. Understand them and you’ll know the secrets to building meaningful relationships that last

This article from The Washington Monthly concludes that pro-Palestinian protests are occurring largely at elite colleges in the U.S., but does suffer from a lack of statistical analysis. Readers are thus forced to use the EB Test (Eyeball Test), which does seem to support that conclusion, but as a scientist I’d like to see some p values.

Click the headline to read; the magazine appears to be pretty nonpartisan, perhaps leaning a bit towards the Left:

Here’s the intro, which also explains why they use percentage of students with Pell Grants, which are grants given to medium- or low-income students, , and the grants don’t need to be repaid. Because the maximum Pell Grant is about $7,300 per year, Pell students tend to go to “non-elite” colleges that don’t charge very much.  Thus the higher the percentage of Pell-funded students, the less “elite” the college is (remember, for schools like Harvard, the yearly tuition, fees, and costs of living are nearly $85.000 before financial aid is applied).

Here’s their intro:

. . . . one thing is not especially diverse about the protests: the campuses on which they’ve been happening.

Many of the most high-profile protests have occurred at highly selective colleges, like Columbia University. But since the national media is famously obsessed with these schools and gives far less attention to the thousands of other colleges where most Americans get their postsecondary educations, it’s hard to know how widespread the campus unrest has really been.

We at the Washington Monthly tried to get to the bottom of this question: Have pro-Palestinian protests taken place disproportionately at elite colleges, where few students come from lower-income families?

The answer is a resounding yes.

Using data from Harvard’s Crowd Counting Consortium and news reports of encampments, we matched information on every institution of higher education that has had pro-Palestinian protest activity (starting when the war broke out in October until early May) to the colleges in our 2023 college rankings. Of the 1,421 public and private nonprofit colleges that we ranked, 318 have had protests and 123 have had encampments.

By matching that data to percentages of students at each campus who receive Pell Grants (which are awarded to students from moderate- and low-income families), we came to an unsurprising conclusion: Pro-Palestinian protests have been rare at colleges with high percentages of Pell students. Encampments at such colleges have been rarer still. A few outliers exist, such as Cal State Los Angeles, the City College of New York, and Rutgers University–Newark. But in the vast majority of cases, campuses that educate students mostly from working-class backgrounds have not had any protest activity. For example, at the 78 historically Black colleges and universities (HBCUs) on the Monthly’s list, 64 percent of the students, on average, receive Pell Grants. Yet according to our data, none of those institutions have had encampments and only nine have had protests, a significantly lower rate than non-HBCU schools.

They give four graphs to support the conclusion, which you can inspect using the EB test. Each point represents one college, and is colored blue if that college had no pro-Palestinian protest, red if there was a protest but no encampment, and green if there was an encampment.  The first graph below shows that “elite” college with fewer students admitted also have a very low percentage of Pell-receiving students, while schools with high percentage of Pell students tend to be those with pretty high admission rates.

Note that nearly all schools with a Pell percentage of 60% or more students (that is, the less selective colleges) have blue dots, reflecting no protests, while those with lower  (40% or less) Pell students have more bluered and green dots, indicating protests. The EB test suggests the hypothesis of “elite = protests” is right, but a statistical analysis would be better (for example, dividing the graph into quartiles along the X axis.

Here’s the notes on the second graph, which plots percentage of Pell students versus tuition and fees for only PRIVATE universities. Their notes:

When you separate out private and public colleges, the difference becomes even more stark, as the next chart demonstrates. At private colleges, protests have been rare, encampments have been rarer, and both have taken place almost exclusively at schools where poorer students are scarce and the listed tuition and fees are exorbitantly high.

. . . Out of the hundreds of private colleges where more than 25 percent of the students receive Pell Grants, only five colleges have had encampments.

You can see that by looking at the plethora of red and green dots (protests and encampments, respectively) at the upper left of the plot, which represents colleges with high tuition and fees and low percentage of Pell students.  Using the EB test alone you see that there are more protests at less affordable colleges.

But what about public universities? The relationship isn’t as clear for public universities, though again there’s a deficit of protests at colleges with more then 50% Pells students. The authors have an explanation for the weaker relationship in public schools. As they say,

Protests and encampments have been more common at public colleges. This is in part because these colleges just have more students, and only a few students are needed for a protest. Even at public colleges, though, there is a clear relationship between having fewer Pell students and having had a protest or encampment, as the chart below illustrates.

The relationship is not as “clear” to me, which is why one needs statistics. Still, nearly all schools with less than 15% Pell students have had a protest or encampment.

Their tentative hypothesis from the above is this:

One possible explanation is that the more selective and wealthier colleges attract and encourage students who are more public minded and socially active.

To test that, they did the same correlation of percent pell students on the X axis versus the 2023 “service ranking” of schools, which are metrics used by the authors to determine the degree of “public mindedness and social activeness”; they incorporate things like “the number of students at a college who serve—before, during, or after attending the school—in AmeriCorps, the Peace Corps, ROTC, and local community nonprofits through work study; the percentage of students registered to vote and the degree to which the school makes student voting easier; and whether a school is listed on the Carnegie Community Engagement Classification, which recognizes colleges that document their broader public engagement efforts.”

The authors note that this relationship (graph below) shows the following:

. . . . schools that have high scores on the Washington Monthly service rankings (the bottom of the Y axis) are a bit more likely to also have had protests and encampments. But in general, the distribution looks more random, especially compared with the previous three charts. In other words, having high levels of student democratic engagement—at least according to the Monthly’s metrics, which are the most extensive we know of—is far less correlated with protests and encampments than admitting low percentages of poor and working-class students.

Well, yes, but again statistics would be nice here, though the plot does look a bit less dispositive that the several above.

The obvious conclusion, which the authors arrive at and I share: students at elite schools  are poorer and “are just focused on other concerns.” As they say:

They may have off-campus jobs and nearby family members to see and take care of. They might sympathize with the protesters—a nationwide poll of college students in May found that 45 percent support the encampments, 24 percent oppose them, and 30 percent are neutral. But in the same poll, only 13 percent rated conflict in the Middle East as the issue most important to them. That was well behind health care reform (40 percent), educational funding and access (38 percent), and economic fairness and opportunity (37 percent). Students burdened with multiple responsibilities—like having to work a low-paying job to pay for college to get a better-paying job—are unlikely to devote what little free time they have to protesting about an issue they don’t see as a high priority.

They also float the idea that schools with more Pell grants are more Left-leaning, and thus more prone to having protests.  This would rest on the notion that bigger schools that are less elite are also located in more conservative areas.

Regardless, the data above–though again I’d like statistical verification–show that the more elite a college is, the more likely it is to have pro-Palestinian protests. This of course jibes with “common wisdom”.  It is the entitled students who protest the most.

A team has analyzed the risk and damage potential of hydrogen vehicles in tunnels and derived recommendations. Their conclusion? Any damage would be extensive, but its occurrence is unlikely.

Team develops a high-energy, high-efficiency all-solid-state Na-air battery platform.