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Engineers have trained a humanoid robot to perform a variety of expressive movements, from simple dance routines to gestures like waving, high-fiving and hugging, all while maintaining a steady gait on diverse terrains. This work marks a step towards building robots that perform more complex and human-like motions.

Without additional regulation, burning ammonia in ship engines could cause serious impacts on air quality that could result in more than 600,000 additional premature deaths per year, according to new research.

Canada has been proving itself the most spineless country in the world when it comes to dealing with illegal campus activism (or other performative activism). Take, for example, The University of Windsor in Ontario, which until now I thought was a respectable university. They’ve had an encampment for two months, and the students, as usual, made a number of demands before they’d take it down.  But in a sickening display of cowardice, Windsor University made a deal with the students, one in which the University capitulates to a number of ridiculous demands. I receive a copy of what is purported to be the agreement, and will send it to you if you ask (it’s too long to reproduce here). But I’ll put some of the agreements below.

UPDATE: I now realized that the agreement is linked to in the CBC report (here), so I don’t need to send it to you. But the copy I received is very slightly different from that at the CBC link (the latter, for example, calls for an academic boycott of Israel, while that bit has been crossed out in what I received.)

First, though, here’s an article from the CBC news site that describes the agreement. Click headline to read:

And the story.  I’ll put below the specifics from the agreement that i was sent. Bolding is mine.

The University of Windsor says it’s reached a deal with students with a pro-Palestinian encampment that began in mid-May, and all tents will be removed from the southwestern Ontario campus within 48 hours.

“This includes peacefully ending the encampment,” the school said in a news release.

The school says the deal also includes more anti-racism initiatives, support for students impacted by the crisis in Gaza, “responsible” investing, and annual disclosures of direct and indirect public fund investments.

The agreement also involves boycotting institutional partnerships with Israeli universities until the “right of Palestinian self-determination has been realized.”

It’s the “most comprehensive and far-reaching” agreement to come out of Canadian encampment negotiations addressing issues like divestment, academic boycott and anti-Palestinian racism, the protesters said in a statement Wednesday afternoon.The encampment has been in front of the former Dillon Hall since May 13.

Negotiations between the two sides have been going on for four weeks, the group says.

“This deal presents to the students, staff, faculty and community as a whole that the university is willing to take solid steps towards a more transparent and just investment system, and rebuilding Gaza,” said Jana Alrifai, a spokesperson for the protest.

“It is a recognition of its past shortcomings and a commitment to betterment. Most importantly, this would have never happened without the fight and steadfastness of the student movement.”

Here are some other details in the agreement:

• The university will establish anti-Palestinian racism training and education, which will be recommended for faculty, staff and students. The training will be mandatory for the leadership team and board of governors.
• The university has 30 days to set up an anti-oppression website, which will include third-party information and resources on anti-Arab racism, anti-Palestinian racism and Islamophobia.
• Students who part of the encampment won’t get any academic or employment sanctions for participating in or supporting the encampment.

The protesters will hold a 5 p.m. ET news conference on Wednesday.

Their encampment is among numerous ones set up on Canadian campuses since April, related to the Israel-Hamas war that began in October. Most of the encampments have since come down.

On Wednesday, an encampment at Montreal’s McGill University was dismantled as police, some wearing riot gear, and others on bicycles and on horseback, descended near the campus after the university served two eviction notices to protesters.

But we’re talking not about McGill but about Windsor.  As I said, I was sent a copy via an email that said this was the agreement signed by both sides, and will show you a bit of what is in it. If you want to see the whole agreement, go here.

Clicking on the heading will take you to the agreement linked to the CBC report, but the quotes I give below come from what I was sent—with the exception of the call for an academic boycott of Israel (it’s in the CBC linked copy but not in what I got). I cannot vouch for which copy of the agreement is the final one, but there’s almost no difference between them.

And some stuff they agreed on.  CONTENT WARNING:  ARRANT COWARDICE BY CANADIAN ADMINISTRATORS:

The University of Windsor is in the process of developing its first-ever anti-racism policy. A central feature of the policy will be a focus on identity-based oppression, including anti-Arab racism, anti-Palestinian racism and Islamophobia. The University will use its best efforts to complete the process by December 31, 2024. The University commits to including Palestinian, Arab and Muslim voices as part of the policy consultation. Regular updates will be provided on the Vice-President, People, Equity andInclusion’s website.

The University commits to establishing an anti-oppression website within 30 days of the ratification of this agreement, which will include institutional and third party information and resources on anti-Arab racism, anti-Palestinian racism and Islamophobia, linked for the benefit of students, faculty, staff and community members

The University agrees to establish anti-Palestinian racism training and education, which will be recommended for faculty, staff and students. The training and education will be mandatory for the Executive Leadership Team and the Board of Governors members.

The University agrees to make internal research grants available for application by students and faculty on the topic of Palestine in all of its dimensions.

The University agrees that students will not receive any academic or employment sanctions for their participation in, or support for, the encampment, bearing in mind the broad protections provided by the freedoms of expression, association, and assembly

No punishments, as usual!

The University agrees to remove the Aspire Anti-Racism information sheet from its website. [JAC: I don’t know what this website said.]

The University will invest funds as required to extend the Scholars at Risk program for an additional year (to end in 2025). Future institutional support for the program beyond 2025 will be reviewed annually by the University based on the availability of funding. The University will make the securing of funding for the continuation of the Scholars at Risk program a priority in its future financial planning. The University will make special efforts to recruit Palestinian scholars who have been impacted by the occupation of Palestine and the scholasticide in Gaza.

Scholasticide!

The University will endeavour to support students impacted by global conflicts and humanitarian crises, including Palestinian students, who have demonstrated urgent housing needs during the Intersession/Summer term with residence housing.

Provide counselling services for Palestinian, Muslim and BIPOC students which will address the rise of racism and Islamophobia. Ensure the necessary resources to ensure counselling is delivered by racial-trauma-focused therapists

The university will facilitate mental health support groups for students experiencing trauma related to the ongoing occupation of Palestine, not less than quarterly.

Anything about helping Jews or Israelis, or Jewish students affected by the war or antisemitism? I don’t see it. But wait—there are TEN PAGES OF THIS STUFF. And of course Windsor has to change its investment policies to the liking of the encampers:

The University administration agrees to propose to the Board investment committee an expansion of its RI Policy to include a new section on Human Rights and International Law. The section would be modeled after Section C. Climate Change. The section would include a commitment to review the weapons manufacturing industry, with particular attention on companies involved in manufacturing arms used in conflict zones where UN human rights mechanisms or resolutions have determined that serious violations of international human rights, humanitarian or criminal law have occurred. The section would provide an opportunity for the University to develop an operational procedure for its RI Policy based on human rights and international law. This operational procedure would be grounded in United Nations resolutions on human rights situations, and the work of the United Nations High Commissioner for Human Rights, the United Nations Special Procedures and United Nations human rights commissions of inquiry as well as decisions of domestic legal bodies.

The University will prepare an annual responsible investing report, disclosing all investments in indirect, direct and pooled funds held in its Pension Fund, Endowment Fund and Working Capital Fund. The report shall be made publicly available. The first report will be published by December 31, 2024. The annual disclosure will provide a list of public companies within the indirect,direct and pooled funds and the amount of investments in each fund The annual disclosure will explain the application of the RI Policy, including the ESG factors and human rights, to the University’s investment decisions.

The University acknowledges the dire situation faced by Palestinian universities under Israeli occupation. This includes the destruction of the Palestinian universities in Gaza and the unjustified restrictions and frequent closures faced by Palestinian universities in East Jerusalem and the West Bank. The University commits to establishing or reestablishing institutional relationships with Palestinian universities, which will include research partnerships and scholarly exchanges. Within its resources, the University will assist with, and support, the restoration of post-secondary education in Gaza.

The University will recommend to the Senate that it explore the feasibility of implementing a Palestine Studies minor under the Interdisciplinary and Critical Studies Department. Courses under this program will aim to explore Palestine in all of its dimensions.

Finally, the encampers have forced the University to violate institutional neutrality and agree with the UN’s demonization of Israel.  Windsor has no fricking business to weigh in on the war or politics, for it violates institutional neutrality by taking an official University position on the war. That, of course, chills the speech of those (presumably many) who disagree with the agreement and the stuff that Windsor will say in its capitulation:

Within 72 hours of the ratification of this agreement, the University will send a letter to the Government of Canada calling for an immediate and permanent ceasefire. In the letter, it will also urge the Government of Canada to include anti-Palestinian racism within its Anti-Racism Strategy. Further, it will request that the Government of Canada should be generous in the humanitarian aid that it delivers to Palestine in order to enable Gaza to engage in reconstruction for its people, and to assist the Palestinians to realize their right to self-determination. The University will post the letter on its website.

This is in the document linked to at the CBC site, but is crossed out in the copy I was sent. If it really was agreed on, it calls for an academic boycott of Israel.

The University does not hold any active institutional academic partnerships with Israeli institutions. Because of the challenging environment for academic collaboration the University agrees to not pursue any institutional academic agreements with Israeli universities until the right of Palestinian self-determination has been realized, as determined by the United Nations, unless supported by Senate. This does not prevent individual academics at the University of Windsor from working (or collaborating) with academics in Israel.

Finally, there’s this—more taking sides in a conflict and more chilling of speech at Windsor:

For the purposes of the application of its RI Policy, the University recognizes that the United Nations, through its various bodies – including the Secretary General, the Security Council, the General Assembly, the Human Rights Council, the International Court of Justice and human rights commissions of inquiry – has found Israel, the occupying power, to be in serious violation of international law and human rights in the conduct of its occupation of Palestinian territory. It also recognizes that the UN Office of the High Commissioner for Human Rights has established an active database of companies whom it has identified are engaged with the illegal Israeli settlement enterprise in the occupied Palestinian territory.

Of course there’s bupkes about Hamas violating international law.

This whole document is simply reprehensible, a sickening display of cowardice (and antisemitism) on the part of Windsor University, which commits itself to taking the side of Hamas in the war and providing resources to Palestine and Palestinian students that aren’t offered to Israeli or Jewish students. There are plenty of initiatives against “Islamophobia,” but I don’t see a single one against antisemitism. Does Windsor do all this stuff for Israeli academics, professors, and students? Perhaps they already have similar policies in place with respect to Israel (extra counseling for Jewish students, etc.), but I doubt it.

Again, if you want to see the whole nauseating agreement, click here.

Thick sea ice is flowing into the Northwest Passage, complicating predictions that melting ice due to climate change will open a shorter route between oceans

A complete genome has been extracted from a 52,000-year-old woolly mammoth, which might bring us closer to resurrecting the species

How do people like to interact with robots when navigating a crowded environment? And what algorithms should roboticists use to program robots to interact with humans? These are the questions that a team of mechanical engineers and computer scientists sought to answer in a recent study.

Water scientists have proposed a more effective method of removing organic pesticides from drinking water, reducing the risk of contamination and potential health problems.

Researchers developed a model showing the ability of reconfigurable intelligent surfaces to redirect the propagation of radio waves, which could improve the signal.

The possibility of hydrogen-powered flight means greater opportunities for fossil-free travel, and the technological advances to make this happen are moving fast. New studies show that almost all air travel within a 750-mile radius (1200 km) could be made with hydrogen-powered aircraft by 2045, and with a novel heat exchanger currently in development, this range could be even further.

By constructing hexagonal metallic-mean approximants of the honeycomb lattice, scientists have linked incommensurately modulated structures and quasicrystals, two classes of aperiodic crystals. They found that a quasicrystal converges to a modulated honeycomb crystal on arranging tiles based on metallic means. This metallic-mean tiling pattern was also identified in polymer and colloidal systems in soft-matter self-assemblies, providing new insights into aperiodic crystals.

A small 3-ounce sensor capable of recording 2,400 data points of movement in just one second being tested and refined by researchers could be key in reducing the number of injuries to racehorses. Researchers used the biometric sensors to track thoroughbreds as they raced and trained at some of the top racetracks in the country. Using collected data, the team was able to identify miniscule stride changes associated with increased risk of injury, allowing intervention before a catastrophic breakdown.

PFAS, the potentially cancer-causing chemicals known as 'forever chemicals', have become an increasing concern in home drinking water. Solutions to reduce the risk of exposure range from mandated municipal-level water treatment to under-the-sink home treatment systems. But are consumers willing to foot the bill for an additional treatment system to help municipalities meet new federal drinking water regulations? Researchers found that they are, if it helps reduce the risk and fits their budget.

Dense E.coli bacteria have several similar qualities to colloidal glass. Colloids are substances made up of small particles suspended within a fluid, like ink for example. When these particles become higher in density and more packed together, they form a 'glassy state.' When researchers multiplied E.coli bacteria within a confined area, they found that they exhibited similar characteristics. More surprisingly, they also showed some other unique properties not typically found in glass-state materials. This study contributes to our understanding of glassy 'active matter,' a relatively new field of materials research which crosses physics and life science. In the long term, the researchers hope that these results will contribute to developing materials with new functional capabilities, as well as aiding our understanding of biofilms (where microorganisms stick together to form layers on surfaces) and natural bacterial colonies.

The qualities and behavior of dark matter, the invisible 'glue' of the universe, continue to be shrouded in mystery. Though galaxies are mostly made of dark matter, understanding how it is distributed within a galaxy offers clues to what this substance is, and how it's relevant to a galaxy's evolution.

On June 11, there was a special issue of Nature with several articles devoted to sex and gender.  In general the two terms were conflated (often used in the phrase “sex and gender”), and most of the issue was an example of a scientific journal being ideologically captured by gender activists. For example, on this site I criticized one of the articles, “Beyond the trans/cis binary: introducing new terms will enrich gender research“, which, as so often happens in science journals, introduces new and “inclusive” terms that, in the end, turn out to be confusing and useless. As I wrote at the time

Nowhere is this more obvious than the essay below, which is not only science-free, but wholly about semantics.  And useless semantics to boot, at least to my eye.  The whole purpose is to introduce a new term, “gender modality,” which, the authors say, will be of great help to people who don’t identify as “male” or “female”, and keep them from being “erased”.  The thing is, the other terms that fall under this rubric already exist, so grouping them as aspects of “gender modality,” a term whose definition is confusing, adds nothing to any social discourse that I can see.

To be sure, a couple of the articles emphasized that in biomedical studies one should be aware of separating males from females when that’s relevant. But if researchers don’t know that by now, I feel sorry for them. And one of the article that scientists should also take gender into account in biomedical research, something that baffles me.  To wit (my emphasis)

For Alzheimer’s and many other diseases that are common causes of death, including cardiovascular diseases, cancer, chronic respiratory conditions and diabetes, a person’s sex and gender can influence their risk of developing the disease, how quickly and accurately they are diagnosed, what treatment they receive and how they fare.

If you’re a tomboy (a female with male-like behaviors), which one can consider a gender identity, does this really affect your chances of getting cancer? If so, I don’t know about it. In fact, I’m not aware that gender can influence any diseases, and no references are given, but I doubt it. (Gender may be important in psychological maladies like gender dysphoria, but that’s not what the authors mean.) This paper is one example of sex and gender, two very different things, being lumped together.  Do not fall into that semantic conflation!

Perhaps it was this mixing up of sex and gender that prompted two researchers to write this newly-published letter in the journal: 

In the main I agree with them, but their arguments don’t really avoid the ‘sex binary,” which is simply the observation that there are two sexes: reproductive systems that are “male” and “female”, with the definitions based on gamete size and mobility, as well as the developmental apparatus that produces eggs and sperm. There are only those two types of gametes, and that’s the case for all animals and nearly all vascular plants.

In animals, which of course include humans, sex is as close to binary as you can come, with only 0.018% of individuals being neither male nor female, but intersex. Yes, some species can change sex, as in clownfish, and some can be hermaphroditic, an individual that is both male and femal at the same time.  But even functional animal (or plant) hermaphrodites still produce only the two types of gametes. And intersex individuals in humans are not a “third sex”, because they don’t produce a third type of gamete.  (In our species, there has never been a case of a hermaphrodite producing both sperm and eggs.)  As Griffiths and Davies wrote in 2020:

The biological definition of sex is not based on an essential quality that every organism is born with, but on two different strategies that organisms use to propagate their genes.

The Griffiths and Davis paper, by the way, is a very good resource for understanding biological sex, though I think it gives away too much to those who claim that they are really members of their non-natal sex.

As for pipefish and seahorses gestating eggs (true), that is a difference in sex ROLES, not sex itself. The same goes for female hyenas that have penis-like structures: they still produce eggs and produce offspring (through that penis-like structure!), but they remain female.  The sex/gamete binary is real, and it’s important because gamete size differences, universal among animals and nearly all plants, produce a whole world of evolutionary differences, the most important being sexual selection based on differences in reproductive investment. And that helps us understand the evolution of genetically-based differences in morphology and behavior between males and females. (Sexual selection also operates in plants.)  The biological definition of sex is important because it’s both universal and evolutionarily enlightening, similar to the biological definition of “species” (see Chapter 1 of Speciation by Coyne and Orr).

Remember, there’s a difference between the DEFINITION of sex (given above) and the ASCERTAINMENT of sex, with the latter made using secondary sexual traits like genitalia. Importantly, the traits used for ascertainment, which include chromosome complement, aren’t always a perfect correlate with biological sex. Still, those traits are used to ASCERTAIN sex, not to “assign” it, as in the ludicrous phrase “sex assigned at birth” or worse, “gender assigned at birth”. Those phrases should be completely eliminated because they’re a sop to the ignorant.  Gender, which involves how a person identifies vis-à-vis sex, and can involve a mixture of male and female traits, non-natal traits, or even nonhuman traits, is completely different from biological sex, and cannot be assigned at birth.

I sent my comments to Matthew, who added this:

The key point, of course, is that the vast majority of people are only interested in humans, where we cannot switch the kind of gametes we produce. There are no cases of this ever recorded, nor will there ever be. People can now do all sorts of things to alter their secondary sex characteristics, and – much more easily – to change their sex roles, but they can’t change the gametes they are born to produce, nor, in the case of people with disorders of sexual development, change their particular fundamental sex characteristics.

And although some species can change sex, either naturally (clownfish), or by being manipulated (crabs with parasites), they are extremely rare and I don’t know of any mammals that do this.

QED

(h/t to Matthew for finding the letter and for his comments)

Adding a polymer-alcohol mixture to menstrual pads causes blood to solidify, rather than being absorbed, which could ward off leaks

You might think I’m about to tell a joke. But no, not me. This is serious physics, folks!

Suppose a particle falls into a hole, and, as in a nightmare (or as in a certain 1970s movie featuring light sabers), the walls of the hole start closing in. The particle will just stay there, awaiting the end. But if the same thing happens to a wavicle, the outcome is very different. Like a magician, the wavicle will escape!

Today I’ll explain why.

As I described last time, stationary particles, waves and wavicles differ in their basic properties.

stationary particlestanding wavestanding waviclelocationdefiniteindefiniteindefiniteenergydefinite,
container-independentadjustabledefinite,
fixed by frequencyfrequencynonecontainer-dependentcontainer-dependentamplitudenoneadjustablefixed by
frequency & container
A stationary particle, standing wave, and standing wavicle, placed in an identical constrained space and with the lowest possible energy that they can have, exhibit quite different properties.

Stationary particles can have a fixed position and energy. Stationary (i.e. standing) waves have a definite frequency, but variable amplitude and energy. And standing wavicles are somewhere in between, with no fixed position, but with a definite frequency and energy. Let’s explore an important consequence of these differences.

The Collapsing Well

Imagine that we place a tiny object at the bottom of a deep but wide well. Then we bring the walls of the well together, making it narrower and narrower. What happens?

A particle will just sit patiently at the bottom of the well, even as the walls close in, seemingly unaware of or unconcerned about its impending doom (Fig. 1).

Figure 1: As the walls of a well draw closer together, a particle in the well seems oblivious; it sits quietly awaiting its fate, its energy unchanging.

A wavicle, by contrast, can’t bear this situation (Fig. 2). Inevitably, as the walls approach each other, the wavicle will always leap bodily out of the well, avoiding ever being trapped.

Figure 2: As the walls of a well draw closer together, a wavicle becomes more and more active, with more and more energy; and at some point it can hop out of the well.

The only way to keep a wavicle inside a collapsing well would be to extend the walls of the well upward, making them infinitely high.

This difference between particles and wavicles has a big impact on our world, and on the atoms and subatomic “particles” out of which we are made.

Energy Between Walls

In my last post I discussed what happens to a particle located between two walls that are separated by a distance L, as in Fig. 3. If the particle has rest mass m and is stationary, it will have energy E=mc2, no matter what L is.

Figure 3: A particle sits on the ground between walls a distance L apart.

A wavicle standing between two walls is different, because the energy of the wavicle grows when L decreases, and vice versa. A wavicle of mass m will therefore have energy larger than mc2.

Figure 4: A standing wavicle sits on the ground, occupying the space between walls a distance L apart.

The energy will be just a little larger than mc2 if the distance L is long, specifically much longer than the wavicle’s “Compton wavelength” h c / m (where h, Planck’s constant, is a constant of nature, like c). But if L is much shorter than the Compton wavelength, then the wavicle’s energy can greatly exceed mc2.

Click here for a math formula showing some details.

Throughout this post I’m going to be quantitatively imprecise, keeping only those conceptual and mathematical features which are needed for the conceptual lessons. A complete mathematical treatment is possible, but I think it would be less instructive and more confusing.

Roughly speaking, the formula for the wavicle’s energy is

Notice that

• if is infinite,
• if is large, , just slightly larger than
• if is small, , much larger than

Energy in a Well

Now let’s imagine digging a hole that has a width W and a depth D, as shown in Fig. 5. Let’s first imagine the well is quite wide, so W is relatively large.

Figure 5: As in Fig. 1, a particle sits in a well of width W and depth D.

If we put a stationary particle of mass m in the well, it just sits at the bottom. How much energy does it have?

If a particle placed at ground level, outside the well, has energy E=mc2, then a particle below ground level at a depth D has energy

• ,

where g is the acceleration of objects due to the Earth’s gravity. The energy has been reduced by the lowering of the particle’s altitude; the larger is D, the greater the reduction. (This reflects the fact that in a hole of greater depth, it would take more energy to lift the particle out of the hole.) But the particle’s energy shows no dependence on W.

Suppose we instead put a stationary wavicle of mass m in a wide well. It too sits inside the well, but it’s different in detail. It vibrates as a standing wave whose length is set by W, and whose frequency f therefore also depends on W. Since a wavicle’s energy and frequency are proportional, via the Planck-Einstein quantum formula E=fh, that means its energy depends on W too.

Figure 6: As in Fig. 2, a wavicle occupies a well of width W and depth D.

Being in the well, at a reduced altitude, reduces its energy by the same factor m g D that applies for the particle. As before, the larger is D, the greater the reduction.

But the wavicle’s energy gets a boost, relative to that of the particle in the well, because the finite width of the well increases its frequency. The smaller is W, the larger the energy boost from the narrowness of the well.

Thus there is a competition between the well’s depth, which lowers the wavicle’s energy as it does the particle’s, and the well’s width, which raises the wavicle’s energy relative to the particle.

Click here for a math formula showing how this works

Specifically, inside a well of width W and depth D, its energy is approximately

So what happens, now, if the well starts collapsing and the walls close in? What do the particle and wavicle do as W decreases?

Leaping Out of the Well?

As the well becomes narrower, the particle does nothing. Its energy doesn’t depend on the width W of the well, and so the particle doesn’t care how far apart the walls are until they actually come in contact with it. The particle’s energy is always less than the mc2 energy of a particle sitting on the ground outside the hole. That means that the particle never has sufficient energy to leave the hole on its own.

The wavicle is quite another matter. As W decreases, the energy of the wavicle increases. And at some point, when W is small enough, the energy of the wavicle in the well becomes greater than the energy of the wavicle that extends outside the well.

To keep things simple, let’s imagine L to be very large, so large that when outside the well, both the particle’s and wavicle’s energy are almost exactly equal to mc2. In that context, consider Fig. 7, where I show the W-dependence of the energy of four objects:

• the wavicle and particle outside the well (blue), whose energy is independent of D and W,
• the particle in the well (orange), whose energy depends on D but not W,
• the wavicle in the well (green), whose energy depends on both D and W.

Only the last of these depends appreciably on W, which is why the blue and orange lines are straight.

When W is large (at right in the plot,) then the fact that the well is deep assures that the energy of the wavicle in the well (green) is lower than the energy of the wavicle that sits on the ground (blue), filling the whole space. That implies that the wavicle will remain within the well, just as a particle in the well would.

Figure 7: The energy E of a particle or wavicle of mass m in the presence of a well of depth D and width W. Either particle or wavicle, when located outside the well, has energy approximately mc2 (blue line.) A particle in the well has its energy reduced by mgD (orange line.) A wavicle in the well has its energy similarly reduced, but also raised by the finite width of the well (green curve.) For small enough W, the green curve lies above the blue line, and the wavicle can escape the well.

But inevitably, when W is small enough (at left in the plot,) the situation reverses! (How small exactly? It depends on details, specifically on both the mass m and the hole’s depth D.) The wavicle in the narrow well, unlike a wavicle in a wide well, has energy greater than a wavicle outside the well. That means that the wavicle in the narrow well has sufficient energy to leave the well entirely, and to become a standing wave that sits on the ground, occupying the whole region between the outer walls.

Notice this is completely general! No matter how deep we make the well, as long as the depth is finite, there is always a small enough width for which the wavicle’s escape becomes possible.

Wavicles Push Back; Particles Don’t

To say this another way, a wavicle in a narrow well has more energy than one in a wide well. Therefore, squeezing a well with a wavicle in it costs energy, whereas to squeeze a well with a mere particle inside costs none. As we shrink W, adding more and more energy to the system, there will always come a point where the wavicle will have enough energy to pop out of the hole. It’s almost as though the wavicle is springy and resists being compressed. A particle in a well, by contrast, is completely inert.

This remarkable property of wavicles, related to Heisenberg’s uncertainty principle, has enormous implications for atomic physics and subatomic physics. In my next post, we’ll see examples of these implications, ones of central importance in human existence.

———-

Aside: We can also compare wavicles with ordinary, familiar waves. We’ve seen how important it is that shortening a wavicle increases its energy. What about the waves on a guitar string? Can they, too, hop out of a hole?

A vibrating guitar string has a standing wave on it that produces sound waves at a particular frequency, heard as a particular musical note. A guitar player, by shortening the string with one finger, can make the frequency of the wave increase, which makes the musical note higher. But doing so need not increase the energy of the string’s vibration! There is no relation between energy and frequency for an ordinary wave, because the number of wavicles that makes up that wave can change. The frequency might increase, but if the number of wavicles decreases, then the energy could stay the same, or even decrease.

It’s only when the vibrating string’s standing wave consists of a single wavicle (or an unchangeable number of wavicles) that energy must be added to increase frequency.

For this same reason, a large wave in a well need not pop out of the well as its walls contract, because shrinking the well’s size, which may increase the wave’s frequency, need not increase its energy.

What was the greatest invention of human civilization? Arguably it was agriculture, which allowed for civilization itself. Prior to agriculture humans were some combination of hunters, gatherers, scavengers, and fishers. We lived off the land, which was a full-time job. Many communities had to be nomadic, to follow prey and follow the seasons. There were some permanently occupied sites, if they were in proximity to an adequate food source. Food was the ultimate limiting factor on human populations and ingenuity.

Agriculture was therefore a transformative invention, allowing people to stay in one place and develop infrastructure. It also freed up some members of the group to do things other than focus on acquiring food. It made civilization possible. How far back does agriculture go?

The consensus is that agriculture began in earnest about 12,000 years ago, in the fertile crescent that is now Iran, Iraq, Turkey and surrounding regions. Evidence for this includes the remnants of domesticated plants, and also evidence of farming and food processing. In addition there is evidence of domesticated animals, which would have been a source of labor and also an additional food source. There were also some downsides to this shift in lifestyle – relying on a narrow range of plants reduced food diversity and therefore overall nutritional quality. Living with domesticated animals, and in larger populations, also saw the rise of communicable diseases. The latter still plagues humanity. However, successful societies all figured out eventually how to farm a combination of plants that would provide adequate nutrition. You may have noticed that most cultures’ staple foods include some combination of a grain plus a legume – corn and beans, rice and lentils, for example.

It turns out, however, that agriculture likely had far deeper roots. A 2015 study details evidence for farming 23,000 years ago, on the shores of the Sea of Galilee. One of the lines of evidence was the presence of extensive weeds. This may seem counter-intuitive, but weeds thrive in cultivated and disturbed land, and so an unusual concentration of weeds is a marker for farming. There was also the presence of wild oats, wild barley, and wild emmer, in addition to tools for processing these grains and evidence of such processing. Was this a false start that eventually died off and had to be rediscovered, or was sporadic farming part of human behavior in this region for thousands of years before systematic agriculture?

It does make sense that kickstarting agriculture would be difficult. There is a bit of chicken and egg problem – you need a stable community to farm, but you need farming to have a stable community. Perhaps some communities did a little farming on the side.

A second major hurdle – what are you going to plant? I have often engaged in the thought experiment of what it would be like to try to kickstart civilization if you were suddenly transported to a prehistoric society 20 thousand or so years ago. Prior to agriculture there were no domesticated or cultivated plants. What exists in the wild is all barely edible – except for fruits, which evolved to be eaten as a bribe for seed distribution.  But even the wild version of most fruits would be considered horrible by modern standards. Only a handful of plants that humans regularly consume are close to their wild forms – such as raspberries. Most others would be unrecognizable to modern eyes.

It is incredible to think, therefore, of our ancestors planting these barely edible plants as a supplement to their diet. It would have been a lot of work for little return, although when living on the edge of starvation anything increases the chances of survival. And then, literally over thousands of years, picking and replanting seeds from incrementally better varieties slowly transformed these wild plants into modern crops. Seeds therefore became a vital commodity, and were traded far and wide. There is an unbroken connection from those first farmers at least 12,000 years ago, if not longer, to modern farming.

Up until very recently, however, farming was still a labor intensive way to get a steady supply of food. During colonial times, for example, 95% of the population was engaged in farming. That left the other 5% to essentially do everything else. But farming also allowed for huge population growth, so while 5% is a small fraction it is a massive population in absolute numbers – a population of scholars, engineers, inventors, artists, and politicians.

Today only about 2% of the population is engaged in farming, which is able to sustain a population of 8 billion people. That is the revolution of agriculture.

The post The Neolithic Revolution first appeared on NeuroLogica Blog.

Horse therapy helps people with Alzheimer's disease socialise and improves their mood to a greater extent than music therapy, which is more established for supporting people with dementia

Certain exoplanets pique scientists’ interest more than others. Some of the most interesting are those that lie in the habitable zone of their stars. However, not all of those planets would be similar to Earth – in fact, finding a planet about the size of Earth is already stretching the limits of most exoplanet-hunting telescopes. So the scientific community rejoiced when researchers at the Université de Montréal announced they found an exoplanet in the size range of the Earth. However, it appears to be almost entirely covered in water, making it more similar to a giant version of Europa, the ice-covered moon of Jupiter. 

There’s a lot to unpack in the press release describing the discovery. The exoplanet they studied is known as LHS 1140b. It’s located 48 light-years away in the constellation Cetus, making it one of the closest known exoplanets in its star’s habitable zone.

That star, LHS 1140, is only about 20% the size of our Sun, and the energy it puts out is smaller. LHS 1140b is one of two potential exoplanets orbiting it, but until now, scientists have debated whether it was a “mini-Neptune” or a “super-Earth.” If it were a “mini-Neptune,” it would be surrounded by hydrogen gas, but the researchers did not find that.

LHS 1140b has long been a center of attention for astronomers – as Anton Petrov describes here.
Credit – Anton Petrov YouTube Channel

They used “director’s discretionary time,” which means observational time directly assigned by the project’s director of the James Webb Space Telescope (JWST). They combined it with data collected from TESS, Spitzer, and Hubble. After looking closely at LHS 1140 b’s atmosphere, they saw something familiar—nitrogen. This was interesting for a few reasons. First, it ruled out the possibility of LHS 1140b being a “mini-Neptune,” as the hydrogen-rich atmosphere would have been very distinct in the data. 

Second, it is now officially the first known temperate exoplanet to have a “secondary” atmosphere – i.e., one created after the planet’s formation. Nitrogen does not naturally form part of a planet’s atmosphere at the outset and must be developed later through chemical processes. So far, no exoplanets in their star’s habitable zones have been observed with this gas in their atmosphere, though it had long been theorized since our own planet’s atmosphere is so rich in it.

But even more intriguingly, with the possibility that it was a “mini-Neptune” eliminated, it seemed LHS 1140b became a good candidate for a “super-Earth” – about 1.7 times larger than our home planet and 5.6 times its mass. However, the researchers also noticed the planet was much less dense than expected, indicating that about 10-20% of that mass could be water rather than rock.

Fraser discusses how we JWST to find exoplanets.

Having that much water could lead to several different outcomes. First, there is the possibility of LHS 1140b being a “Hycean world,” which would be entirely covered by a liquid-water ocean. This seems unlikely, as the star’s energy output doesn’t provide enough energy to keep an entire planet-sized ocean warm enough not to freeze.

This leads to the second possibility—a “snowball” world where a thick layer of snow covers the rocky interior. This is still possible, but it requires weather patterns that might be hard to discern remotely, even with JWST.

So that leaves a final possibility—an ice world, where thick sheets of ice cover the entirety of the planet’s surface. We already know of one such world a lot closer to home—Europa. It is completely covered in ice, though intriguingly, it also has a liquid ocean underneath those ice sheets. The researchers think there is a good chance a similar subsurface ocean could exist on LHS 1140b as well.

Fraser discusses how to research exoplanet atmospheres with JWST.

That would make it the first known exoplanet to have confirmed liquid water. However, the data suggested another intriguing possibility – it could be a snowball planet with a “bull’s eye ocean” at the point where the star’s heat is strongest on it. This ocean could be around 4,000 km across, about half the size of the Atlantic Ocean on Earth. Models suggest that the water temperature in the ocean could even reach 20 C, a comfortable room temperature, though a bit cold to swim in. 

However, none of these details have been confirmed yet, and doing so will require—you guessed it—more observational time. In particular, the researchers are interested in whether there is carbon dioxide in LHS 1140b’s atmosphere. A greenhouse gas could make it more likely that the planet’s overall temperature would be warm enough to make it a Hycean world rather than a snowball with one isolated ocean. 

Observing carbon dioxide in an exoplanet as far away as LHS 1140 could take years of intermittent observational time on JWST. While LHS 1140b is now definitively one of the most promising candidates for finding liquid water on a planet’s surface – and therefore be a prime candidate for finding life on an exoplanet – continued observation of that kind would have to compete with all the other worthy use cases for JWST’s time. 

For now, the researchers hope to receive more observational time, even if it isn’t enough to confirm the presence of carbon dioxide. However, eventually, there will be more and stronger planet-hunting telescopes than even the JWST. Someday, there will be enough observational time on at least one of them to confirm whether or not LHS 1140b does indeed have a liquid ocean. That day might be one of the most monumental in the history of the study of exoplanets—and maybe for humanity itself.

Learn More:
Université de Montréal – Astronomers Find Surprising Ice World in the Habitable Zone with Webb Data
Cadieux et al. – Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
UT – Is This The Exoplanet Where Life Will First Be Found?
UT – A New Venus-Sized World Found in the Habitable Zone of its Star

Lead Image:
Illustration of exoplanet LHS 1140 b, including a “bulls-eye ocean”.
Credit – B. Gougeon / UdeM

The post Exoplanet Could be an Enormous Version of Europa appeared first on Universe Today.